diff --git a/README.md b/README.md
index 830d162..c042c30 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ browser ──nginx (basic auth, TLS)──▶ /api/* ─▶│ SQLite       │
 - `public/`: static frontend (no build step). Add `?mock=1` to the URL to use built-in sample data.
 - `backend/`: FastAPI API backed by a single SQLite file.
 - `deploy/`: nginx site and systemd unit.
-- `collectors/`: scripts that report results from backup products ([Veeam B&R](collectors/veeam/README.md), [Azure Backup / MARS](collectors/mars/README.md), [Windows Server Backup](collectors/wsb/README.md), [Veeam Backup for M365](collectors/vb365/README.md)).
+- `collectors/`: PowerShell scripts that report results from backup products ([Veeam B&R](collectors/veeam/README.md), [Azure Backup / MARS](collectors/mars/README.md), [Windows Server Backup](collectors/wsb/README.md), [Veeam Backup for M365](collectors/vb365/README.md)). Code they share (config, logging, posting, state, installing) is in `collectors/common/BackupDashboard.Collector.psm1`.
 
 ## Data model
 
diff --git a/collectors/common/BackupDashboard.Collector.psm1 b/collectors/common/BackupDashboard.Collector.psm1
new file mode 100644
index 0000000..76e6014
--- /dev/null
+++ b/collectors/common/BackupDashboard.Collector.psm1
@@ -0,0 +1,270 @@
+<#
+    Shared code for the Backup Dashboard collectors: config and state files, logging, posting to
+    the ingest API, and installing a collector as a scheduled task.
+
+    Each collector imports this from next to itself (installed: C:\Program Files\BackupDashboard)
+    or from ..\common (in the repo). Collectors on the same server share one installed copy, so
+    keep these functions backward compatible.
+
+    Works on Windows PowerShell 5.1 and PowerShell 7.
+#>
+
+$script:Config = $null
+$script:DryRun = $false
+$script:LogPath = $null
+$script:StatePath = $null
+$script:LookbackHours = 48
+$script:Sent = @{}
+$script:RunsSent = 0
+$script:MaxLogBytes = 5MB
+$script:Invariant = [Globalization.CultureInfo]::InvariantCulture
+
+# ---------- Logging and values ----------
+
+function Write-Log {
+    param([string]$Message, [string]$Level = 'INFO')
+    $line = '{0} [{1}] {2}' -f (Get-Date).ToString('yyyy-MM-dd HH:mm:ss'), $Level, $Message
+    Write-Host $line
+    if ($script:DryRun -or -not $script:LogPath) { return }
+    if ((Test-Path $script:LogPath) -and (Get-Item $script:LogPath).Length -gt $script:MaxLogBytes) {
+        Move-Item $script:LogPath "$($script:LogPath).1" -Force
+    }
+    Add-Content -Path $script:LogPath -Value $line -Encoding UTF8
+}
+
+function Get-ErrorText($ErrorRecord) {
+    # Windows PowerShell puts the HTTP response body (e.g. the API's 422 explanation) here
+    if ($ErrorRecord.ErrorDetails -and $ErrorRecord.ErrorDetails.Message) {
+        return "$($ErrorRecord.Exception.Message) $($ErrorRecord.ErrorDetails.Message)"
+    }
+    return $ErrorRecord.Exception.Message
+}
+
+# The API needs an explicit UTC offset. DateTimeOffset keeps a Local/Unspecified time as local and a
+# Utc time as +00:00, so convert UTC-valued times to Kind Utc before calling this.
+function ConvertTo-IsoTime($Value) {
+    if ($null -eq $Value) { return $null }
+    $dt = [datetime]$Value
+    if ($dt.Year -le 1900) { return $null }  # "not set" (DateTime.MinValue, MARS's 1601-01-01, ...)
+    return ([DateTimeOffset]$dt).ToString("yyyy-MM-dd'T'HH:mm:sszzz", $script:Invariant)
+}
+
+# First property of $Object, out of $Names, that exists and isn't empty. Backup products' object
+# models aren't fully documented, so reads go through this rather than assuming one spelling.
+function Get-FirstValue($Object, [string[]]$Names) {
+    if ($null -eq $Object) { return $null }
+    foreach ($name in $Names) {
+        try {
+            $prop = $Object.PSObject.Properties[$name]
+            if (-not $prop) { continue }
+            $value = $prop.Value
+            # Check emptiness by type: casting to [string] would make a one-item list of objects ''
+            if ($null -eq $value) { continue }
+            if ($value -is [string] -and $value -eq '') { continue }
+            if ($value -is [Collections.ICollection] -and $value.Count -eq 0) { continue }
+            return $value
+        } catch { }
+    }
+    return $null
+}
+
+# ---------- Collector run ----------
+
+<#
+    Loads the config ($ConfigPath, JSON) and the record of runs already sent, and sets up logging
+    and TLS. Log and state files sit next to the config: <Name>-collector.log / .state.json.
+    Returns the config object; its LookbackHours is resolved (the parameter, else the config, else
+    48). Throws if the config can't be read or lacks one of $RequiredKeys.
+#>
+function Initialize-Collector {
+    param(
+        [Parameter(Mandatory)][string]$Name,
+        [Parameter(Mandatory)][string]$ConfigPath,
+        [int]$LookbackHours = 0,
+        [switch]$DryRun,
+        [string[]]$RequiredKeys = @('ApiUrl', 'ApiKey', 'Tenant')
+    )
+    # Logging first, so a bad config can still be logged
+    $dataDir = Split-Path -Parent $ConfigPath
+    $script:LogPath = Join-Path $dataDir "$Name-collector.log"
+    $script:StatePath = Join-Path $dataDir "$Name-collector.state.json"
+    $script:DryRun = [bool]$DryRun
+    $script:RunsSent = 0
+    $script:Sent = @{}
+
+    $config = Get-Content -Path $ConfigPath -Raw | ConvertFrom-Json
+    foreach ($key in $RequiredKeys) {
+        if (-not $config.$key) { throw "Config $ConfigPath is missing '$key'" }
+    }
+    if ($LookbackHours -le 0) {
+        $LookbackHours = if ($config.LookbackHours) { [int]$config.LookbackHours } else { 48 }
+    }
+    $config | Add-Member -NotePropertyName LookbackHours -NotePropertyValue $LookbackHours -Force
+    $script:LookbackHours = $LookbackHours
+    $script:Config = $config
+
+    # Windows PowerShell 5.1 may default to TLS 1.0
+    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+
+    # Run key -> start time (Unix seconds), for runs already delivered in their final state.
+    # Numbers rather than ISO strings: PowerShell 7's ConvertFrom-Json turns date strings into
+    # DateTimes and loses the offset.
+    if (Test-Path $script:StatePath) {
+        $saved = Get-Content -Path $script:StatePath -Raw | ConvertFrom-Json
+        if ($saved) { foreach ($p in $saved.PSObject.Properties) { $script:Sent[$p.Name] = [long]$p.Value } }
+    }
+    return $config
+}
+
+function Test-RunSent([string]$Key) {
+    return $script:Sent.ContainsKey($Key)
+}
+
+<#
+    Posts one report to the ingest API: the job alone (to refresh next_run_at) or the job with a
+    run. A run that has finished is then recorded as sent under $SentKey, so later collector runs
+    skip it; a running one isn't, so it's re-sent until it finishes. Throws on an HTTP error.
+#>
+function Send-JobReport {
+    param(
+        [Parameter(Mandatory)][string]$Tenant,
+        [Parameter(Mandatory)][string]$SourceSystem,
+        [Parameter(Mandatory)]$Job,
+        $Run,
+        [string]$SentKey,
+        $StartedAt
+    )
+    $body = [ordered]@{ tenant = $Tenant; source_system = $SourceSystem; job = $Job }
+    if ($Run) { $body.run = $Run }
+    $json = $body | ConvertTo-Json -Depth 6 -Compress
+    if ($script:DryRun) {
+        Write-Host $json
+    } else {
+        # Send bytes: Windows PowerShell would otherwise encode a string body as Latin-1,
+        # mangling non-ASCII job names (e.g. en dashes)
+        $params = @{
+            Uri         = "$($script:Config.ApiUrl.TrimEnd('/'))/api/v1/ingest"
+            Method      = 'Post'
+            Headers     = @{ Authorization = "Bearer $($script:Config.ApiKey)" }
+            ContentType = 'application/json; charset=utf-8'
+            Body        = [Text.Encoding]::UTF8.GetBytes($json)
+            TimeoutSec  = 30
+        }
+        Invoke-RestMethod @params | Out-Null
+    }
+    if ($Run) {
+        $script:RunsSent++
+        if ($Run.status -ne 'running' -and $SentKey) {
+            $script:Sent[$SentKey] = ([DateTimeOffset][datetime]$StartedAt).ToUnixTimeSeconds()
+        }
+    }
+}
+
+# True when a failed Send-JobReport was the API rejecting the key: no point trying more jobs
+function Test-AuthRejected($ErrorRecord) {
+    $status = 0
+    try { $status = [int]$ErrorRecord.Exception.Response.StatusCode } catch { }
+    return $status -eq 401
+}
+
+<#
+    Saves the sent-runs record (dropping runs older than the lookback window plus a day) and logs
+    the summary line. Doesn't exit: the collector does that with the returned exit code.
+#>
+function Complete-Collector {
+    param([int]$JobCount = -1, [int]$Failures = 0)
+    if (-not $script:DryRun) {
+        $cutoff = [DateTimeOffset]::Now.AddHours(-$script:LookbackHours - 24).ToUnixTimeSeconds()
+        $keep = [ordered]@{}
+        foreach ($key in $script:Sent.Keys) {
+            if ($script:Sent[$key] -ge $cutoff) { $keep[$key] = $script:Sent[$key] }
+        }
+        try {
+            $keep | ConvertTo-Json -Compress | Set-Content -Path $script:StatePath -Encoding UTF8
+        } catch {
+            Write-Log "Couldn't save state file: $(Get-ErrorText $_)" 'WARN'
+        }
+    }
+    if ($JobCount -ge 0) {
+        Write-Log ("Reported {0} jobs, {1} runs, {2} failures" -f $JobCount, $script:RunsSent, $Failures)
+    } else {
+        Write-Log ("Reported {0} runs, {1} failures" -f $script:RunsSent, $Failures)
+    }
+    if ($Failures) { return 1 }
+    return 0
+}
+
+# ---------- Installing ----------
+
+<#
+    The part of every collector installer after its own checks: prompt for the API key, write the
+    config to ProgramData\BackupDashboard (locked to SYSTEM and Administrators, since it holds the
+    key), copy the collector script and this module to $InstallDir (Program Files: only admins can
+    modify what runs as SYSTEM), and register a scheduled task running it as SYSTEM.
+#>
+function Install-CollectorTask {
+    param(
+        [Parameter(Mandatory)][string]$Name,           # 'veeam' -> veeam-collector.json / .log
+        [Parameter(Mandatory)][string]$ScriptPath,     # the collector script to install
+        [Parameter(Mandatory)][string]$TaskName,
+        [Parameter(Mandatory)][string]$TaskDescription,
+        [Parameter(Mandatory)][string]$Shell,          # powershell.exe or pwsh.exe, full path
+        [Parameter(Mandatory)][string]$ApiUrl,
+        [Parameter(Mandatory)][int]$IntervalMinutes,
+        [Parameter(Mandatory)][string]$InstallDir,
+        [System.Collections.IDictionary]$Settings = @{}  # extra config: Tenant, LookbackHours, ...
+    )
+    $dataDir = Join-Path $env:ProgramData 'BackupDashboard'
+    $configPath = Join-Path $dataDir "$Name-collector.json"
+
+    if ($ApiUrl -notmatch '^https://') {
+        Write-Warning 'ApiUrl is not HTTPS: the API key would be sent in clear text.'
+    }
+
+    # Read the key as a SecureString so it isn't echoed to the console or kept in shell history
+    $secure = Read-Host -AsSecureString 'API key (from: python manage.py create-key <name>)'
+    $bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($secure)
+    try { $apiKey = [Runtime.InteropServices.Marshal]::PtrToStringBSTR($bstr) }
+    finally { [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr) }
+    if (-not $apiKey.StartsWith('bdk_')) { throw "That doesn't look like a dashboard API key (expected 'bdk_...')." }
+
+    # Config folder: SYSTEM + Administrators only (SIDs so this works on non-English Windows)
+    New-Item -ItemType Directory -Path $dataDir -Force | Out-Null
+    & icacls.exe $dataDir /inheritance:r /grant:r '*S-1-5-18:(OI)(CI)F' '*S-1-5-32-544:(OI)(CI)F' | Out-Null
+    if ($LASTEXITCODE) { throw "icacls failed on $dataDir" }
+
+    $config = [ordered]@{ ApiUrl = $ApiUrl.TrimEnd('/'); ApiKey = $apiKey }
+    foreach ($key in $Settings.Keys) { $config[$key] = $Settings[$key] }
+    $config | ConvertTo-Json -Depth 4 | Set-Content -Path $configPath -Encoding UTF8
+
+    # The collector and this module, side by side (the collector looks for the module next to itself)
+    New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
+    $installedScript = Join-Path $InstallDir (Split-Path -Leaf $ScriptPath)
+    foreach ($file in $ScriptPath, $PSCommandPath) {
+        $target = Join-Path $InstallDir (Split-Path -Leaf $file)
+        Copy-Item -Path $file -Destination $target -Force
+        Unblock-File -Path $target
+    }
+
+    $action = New-ScheduledTaskAction -Execute $Shell `
+        -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$installedScript`""
+    $trigger = New-ScheduledTaskTrigger -Once -At (Get-Date).AddMinutes(1) `
+        -RepetitionInterval (New-TimeSpan -Minutes $IntervalMinutes)
+    $principal = New-ScheduledTaskPrincipal -UserId 'S-1-5-18' -LogonType ServiceAccount -RunLevel Highest
+    $taskSettings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 30) `
+        -MultipleInstances IgnoreNew -StartWhenAvailable
+    Register-ScheduledTask -TaskName $TaskName -Action $action -Trigger $trigger -Principal $principal `
+        -Settings $taskSettings -Description $TaskDescription -Force | Out-Null
+
+    Write-Host "Installed. Config: $configPath"
+    Write-Host "Task '$TaskName' runs every $IntervalMinutes minutes as SYSTEM, using $Shell."
+    Write-Host ''
+    Write-Host 'Next steps:'
+    Write-Host "  1. Preview what will be sent:   & '$Shell' -File '$installedScript' -DryRun"
+    Write-Host "  2. Backfill 30 days of history: & '$Shell' -File '$installedScript' -LookbackHours 720"
+    Write-Host "  3. Check the log:               Get-Content '$dataDir\$Name-collector.log' -Tail 20"
+}
+
+Export-ModuleMember -Function Write-Log, Get-ErrorText, ConvertTo-IsoTime, Get-FirstValue,
+    Initialize-Collector, Test-RunSent, Send-JobReport, Test-AuthRejected, Complete-Collector,
+    Install-CollectorTask
diff --git a/collectors/mars/Install-MarsCollector.ps1 b/collectors/mars/Install-MarsCollector.ps1
index 0be60d0..d4f802f 100644
--- a/collectors/mars/Install-MarsCollector.ps1
+++ b/collectors/mars/Install-MarsCollector.ps1
@@ -29,9 +29,6 @@ param(
 )
 
 $ErrorActionPreference = 'Stop'
-$TaskName = 'Backup Dashboard - MARS collector'
-$DataDir = Join-Path $env:ProgramData 'BackupDashboard'
-$ConfigPath = Join-Path $DataDir 'mars-collector.json'
 $WindowsPowerShell = Join-Path $env:SystemRoot 'System32\WindowsPowerShell\v1.0\powershell.exe'
 
 # Check the agent is here before changing anything
@@ -40,51 +37,19 @@ if (-not (Get-Module -ListAvailable -Name MSOnlineBackup) -and -not (Test-Path $
     throw 'The MARS agent (MSOnlineBackup PowerShell module) is not installed on this server.'
 }
 
-if ($ApiUrl -notmatch '^https://') {
-    Write-Warning 'ApiUrl is not HTTPS: the API key would be sent in clear text.'
+# Shared installer code: in the repo it's in ..\common, so copy the whole collectors folder
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    throw "BackupDashboard.Collector.psm1 not found. Copy the whole collectors folder, including common."
 }
+Import-Module $sharedModule -Force
 
-# Read the key as a SecureString so it isn't echoed to the console or kept in shell history
-$secure = Read-Host -AsSecureString 'API key (from: python manage.py create-key <name>)'
-$bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($secure)
-try { $apiKey = [Runtime.InteropServices.Marshal]::PtrToStringBSTR($bstr) }
-finally { [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr) }
-if (-not $apiKey.StartsWith('bdk_')) { throw "That doesn't look like a dashboard API key (expected 'bdk_...')." }
-
-# Config folder: SYSTEM + Administrators only (SIDs so this works on non-English Windows)
-New-Item -ItemType Directory -Path $DataDir -Force | Out-Null
-& icacls.exe $DataDir /inheritance:r /grant:r '*S-1-5-18:(OI)(CI)F' '*S-1-5-32-544:(OI)(CI)F' | Out-Null
-if ($LASTEXITCODE) { throw "icacls failed on $DataDir" }
-
-$config = [ordered]@{
-    ApiUrl        = $ApiUrl.TrimEnd('/')
-    ApiKey        = $apiKey
-    Tenant        = $Tenant
-    SourceSystem  = $SourceSystem
-    LookbackHours = $LookbackHours
-}
-if ($JobName) { $config.JobName = $JobName }
-$config | ConvertTo-Json | Set-Content -Path $ConfigPath -Encoding UTF8
-
-New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
-$scriptPath = Join-Path $InstallDir 'Send-MarsBackupStatus.ps1'
-Copy-Item -Path (Join-Path $PSScriptRoot 'Send-MarsBackupStatus.ps1') -Destination $scriptPath -Force
-Unblock-File -Path $scriptPath
-
-$action = New-ScheduledTaskAction -Execute $WindowsPowerShell `
-    -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$scriptPath`""
-$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date).AddMinutes(1) `
-    -RepetitionInterval (New-TimeSpan -Minutes $IntervalMinutes)
-$principal = New-ScheduledTaskPrincipal -UserId 'S-1-5-18' -LogonType ServiceAccount -RunLevel Highest
-$settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 30) `
-    -MultipleInstances IgnoreNew -StartWhenAvailable
-Register-ScheduledTask -TaskName $TaskName -Action $action -Trigger $trigger -Principal $principal `
-    -Settings $settings -Description 'Sends Azure Backup (MARS) results to the Backup Dashboard' -Force | Out-Null
-
-Write-Host "Installed. Config: $ConfigPath"
-Write-Host "Task '$TaskName' runs every $IntervalMinutes minutes as SYSTEM, using Windows PowerShell."
-Write-Host ''
-Write-Host 'Next steps:'
-Write-Host "  1. Preview what will be sent:   & '$WindowsPowerShell' -File '$scriptPath' -DryRun"
-Write-Host "  2. Backfill 30 days of history: & '$WindowsPowerShell' -File '$scriptPath' -LookbackHours 720"
-Write-Host "  3. Check the log:               Get-Content '$DataDir\mars-collector.log' -Tail 20"
+$settings = [ordered]@{ Tenant = $Tenant; SourceSystem = $SourceSystem; LookbackHours = $LookbackHours }
+if ($JobName) { $settings.JobName = $JobName }
+Install-CollectorTask -Name 'mars' -ScriptPath (Join-Path $PSScriptRoot 'Send-MarsBackupStatus.ps1') `
+    -TaskName 'Backup Dashboard - MARS collector' `
+    -TaskDescription 'Sends Azure Backup (MARS) results to the Backup Dashboard' `
+    -Shell $WindowsPowerShell -ApiUrl $ApiUrl -IntervalMinutes $IntervalMinutes -InstallDir $InstallDir -Settings $settings
diff --git a/collectors/mars/README.md b/collectors/mars/README.md
index 9134852..6c854eb 100644
--- a/collectors/mars/README.md
+++ b/collectors/mars/README.md
@@ -18,7 +18,8 @@ targets and which every supported Windows Server has.
    ```bash
    python manage.py create-key mars-acme-fs01
    ```
-2. Copy this folder to the server and run:
+2. Copy the whole `collectors` folder to the server (the installer needs `common`
+   as well as this folder), then from `collectors\mars` run:
    ```powershell
    .\Install-MarsCollector.ps1 -ApiUrl https://backups.example.com -Tenant "Acme Corp"
    ```
@@ -33,8 +34,9 @@ targets and which every supported Windows Server has.
    powershell.exe -File 'C:\Program Files\BackupDashboard\Send-MarsBackupStatus.ps1' -LookbackHours 720
    ```
 
-It can be installed alongside the Veeam collector: it uses its own config, state, log and task.
-Re-run the installer to change settings or update the script.
+It can be installed alongside the other collectors: it uses its own config, state, log and task.
+Re-run the installer to change settings or update the script. It also installs
+`BackupDashboard.Collector.psm1`, the code shared by all collectors, next to the script.
 
 ## What it sends
 
diff --git a/collectors/mars/Send-MarsBackupStatus.ps1 b/collectors/mars/Send-MarsBackupStatus.ps1
index 8ebaeb8..109d76b 100644
--- a/collectors/mars/Send-MarsBackupStatus.ps1
+++ b/collectors/mars/Send-MarsBackupStatus.ps1
@@ -38,63 +38,22 @@ param(
 
 $ErrorActionPreference = 'Stop'
 
-$DataDir = Split-Path -Parent $ConfigPath
-$LogPath = Join-Path $DataDir 'mars-collector.log'
-$StatePath = Join-Path $DataDir 'mars-collector.state.json'
-$MaxLogBytes = 5MB
+# Shared collector code: installed next to this script; in the repo, in ..\common
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    Write-Host "BackupDashboard.Collector.psm1 not found next to $PSCommandPath; re-run the installer."
+    exit 2
+}
+Import-Module $sharedModule -Force
+
 # MARS keeps a limited job history; this comfortably covers 30 days at 3 backups a day
 $MaxPreviousJobs = 200
-$Invariant = [Globalization.CultureInfo]::InvariantCulture
 
 # ---------- Helpers ----------
 
-function Write-Log {
-    param([string]$Message, [string]$Level = 'INFO')
-    $line = '{0} [{1}] {2}' -f (Get-Date).ToString('yyyy-MM-dd HH:mm:ss'), $Level, $Message
-    Write-Host $line
-    if ($DryRun) { return }
-    if ((Test-Path $LogPath) -and (Get-Item $LogPath).Length -gt $MaxLogBytes) {
-        Move-Item $LogPath "$LogPath.1" -Force
-    }
-    Add-Content -Path $LogPath -Value $line -Encoding UTF8
-}
-
-function Get-ErrorText($ErrorRecord) {
-    # Windows PowerShell puts the HTTP response body (e.g. the API's 422 explanation) here
-    if ($ErrorRecord.ErrorDetails -and $ErrorRecord.ErrorDetails.Message) {
-        return "$($ErrorRecord.Exception.Message) $($ErrorRecord.ErrorDetails.Message)"
-    }
-    return $ErrorRecord.Exception.Message
-}
-
-# The API needs an explicit UTC offset. DateTimeOffset keeps a Local/Unspecified time as local and a
-# Utc time as +00:00.
-function ConvertTo-IsoTime($Value) {
-    if ($null -eq $Value) { return $null }
-    $dt = [datetime]$Value
-    if ($dt.Year -le 1900) { return $null }  # "not set" (MARS uses 1601-01-01)
-    return ([DateTimeOffset]$dt).ToString("yyyy-MM-dd'T'HH:mm:sszzz", $Invariant)
-}
-
-# First property of $Object, out of $Names, that exists and isn't empty. MARS object property names
-# aren't documented, so reads go through this rather than assuming one spelling.
-function Get-FirstValue($Object, [string[]]$Names) {
-    if ($null -eq $Object) { return $null }
-    foreach ($name in $Names) {
-        try {
-            $prop = $Object.PSObject.Properties[$name]
-            if (-not $prop) { continue }
-            $value = $prop.Value
-            # Check emptiness by type: casting to [string] would make a one-item list of objects ''
-            if ($null -eq $value) { continue }
-            if ($value -is [string] -and $value -eq '') { continue }
-            if ($value -is [Collections.ICollection] -and $value.Count -eq 0) { continue }
-            return $value
-        } catch { }
-    }
-    return $null
-}
-
 function Import-Mars {
     if (Get-Command Get-OBJob -ErrorAction SilentlyContinue) { return }  # already loaded
     if (Get-Module -ListAvailable -Name MSOnlineBackup) {
@@ -305,49 +264,16 @@ function Test-IsBackupJob($Job) {
     return (-not $type) -or $type -match 'Backup'
 }
 
-function Send-Report($Body) {
-    $json = $Body | ConvertTo-Json -Depth 6 -Compress
-    if ($DryRun) {
-        Write-Host $json
-        return
-    }
-    # Send bytes: Windows PowerShell would otherwise encode a string body as Latin-1
-    $params = @{
-        Uri         = "$($Config.ApiUrl.TrimEnd('/'))/api/v1/ingest"
-        Method      = 'Post'
-        Headers     = @{ Authorization = "Bearer $($Config.ApiKey)" }
-        ContentType = 'application/json; charset=utf-8'
-        Body        = [Text.Encoding]::UTF8.GetBytes($json)
-        TimeoutSec  = 30
-    }
-    Invoke-RestMethod @params | Out-Null
-}
-
 # ---------- Main ----------
 
 try {
-    $Config = Get-Content -Path $ConfigPath -Raw | ConvertFrom-Json
-    foreach ($key in 'ApiUrl', 'ApiKey', 'Tenant') {
-        if (-not $Config.$key) { throw "Config $ConfigPath is missing '$key'" }
-    }
+    $Config = Initialize-Collector -Name 'mars' -ConfigPath $ConfigPath -LookbackHours $LookbackHours -DryRun:$DryRun
     $SourceSystem = if ($Config.SourceSystem) { [string]$Config.SourceSystem } else { 'Azure Backup (MARS)' }
     $JobName = if ($Config.JobName) { [string]$Config.JobName } else { "$env:COMPUTERNAME - Azure Backup" }
-    if ($LookbackHours -le 0) {
-        $LookbackHours = if ($Config.LookbackHours) { [int]$Config.LookbackHours } else { 48 }
-    }
-
-    # Windows PowerShell 5.1 may default to TLS 1.0
-    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+    $LookbackHours = $Config.LookbackHours
 
     Import-Mars
 
-    # Job ID -> start time (Unix seconds), for jobs already delivered in their final state
-    $sent = @{}
-    if (Test-Path $StatePath) {
-        $saved = Get-Content -Path $StatePath -Raw | ConvertFrom-Json
-        if ($saved) { foreach ($p in $saved.PSObject.Properties) { $sent[$p.Name] = [long]$p.Value } }
-    }
-
     $sinceUtc = (Get-Date).ToUniversalTime().AddHours(-$LookbackHours)
     # Get-OBJob with no arguments lists jobs in progress; -Previous lists finished ones
     $jobs = @(@(Get-OBJob) + @(Get-OBJob -Previous $MaxPreviousJobs) | Where-Object {
@@ -360,7 +286,7 @@ try {
         $byId[[string]$job.JobId] = $job  # a job in both lists: the finished entry (later) wins
     }
     $pending = @($byId.Values |
-        Where-Object { -not $sent.ContainsKey([string]$_.JobId) } |
+        Where-Object { -not (Test-RunSent ([string]$_.JobId)) } |
         Sort-Object { Get-JobTimeUtc $_ 'StartTime' })
 
     $jobInfo = [ordered]@{
@@ -376,38 +302,19 @@ try {
 }
 
 $failures = 0
-$runsSent = 0
 try {
     if ($pending.Count -eq 0) {
         # Keep next_run_at fresh even when nothing new ran
-        Send-Report ([ordered]@{ tenant = $Config.Tenant; source_system = $SourceSystem; job = $jobInfo })
+        Send-JobReport -Tenant $Config.Tenant -SourceSystem $SourceSystem -Job $jobInfo
     }
     foreach ($job in $pending) {
         $run = ConvertTo-Run $job
-        Send-Report ([ordered]@{ tenant = $Config.Tenant; source_system = $SourceSystem; job = $jobInfo; run = $run })
-        $runsSent++
-        if ($run.status -ne 'running') {
-            $sent[$run.external_id] = ([DateTimeOffset](Get-JobTimeUtc $job 'StartTime')).ToUnixTimeSeconds()
-        }
+        Send-JobReport -Tenant $Config.Tenant -SourceSystem $SourceSystem -Job $jobInfo -Run $run -SentKey $run.external_id -StartedAt ((Get-JobTimeUtc $job 'StartTime'))
     }
 } catch {
     $failures++
     Write-Log "Failed to report: $(Get-ErrorText $_)" 'ERROR'
 }
 
-if (-not $DryRun) {
-    # Forget jobs that have aged out of the lookback window (plus a day of slack)
-    $cutoff = [DateTimeOffset]::Now.AddHours(-$LookbackHours - 24).ToUnixTimeSeconds()
-    $keep = [ordered]@{}
-    foreach ($id in $sent.Keys) {
-        if ($sent[$id] -ge $cutoff) { $keep[$id] = $sent[$id] }
-    }
-    try {
-        $keep | ConvertTo-Json -Compress | Set-Content -Path $StatePath -Encoding UTF8
-    } catch {
-        Write-Log "Couldn't save state file: $(Get-ErrorText $_)" 'WARN'
-    }
-}
-
-Write-Log ("Reported {0} runs, {1} failures" -f $runsSent, $failures)
-if ($failures) { exit 1 }
+$exitCode = Complete-Collector -Failures $failures
+if ($exitCode) { exit $exitCode }
diff --git a/collectors/vb365/Install-Vb365Collector.ps1 b/collectors/vb365/Install-Vb365Collector.ps1
index b11e1fd..c6a9891 100644
--- a/collectors/vb365/Install-Vb365Collector.ps1
+++ b/collectors/vb365/Install-Vb365Collector.ps1
@@ -37,9 +37,6 @@ param(
 )
 
 $ErrorActionPreference = 'Stop'
-$TaskName = 'Backup Dashboard - VB365 collector'
-$DataDir = Join-Path $env:ProgramData 'BackupDashboard'
-$ConfigPath = Join-Path $DataDir 'vb365-collector.json'
 $Shell = Join-Path $env:SystemRoot 'System32\WindowsPowerShell\v1.0\powershell.exe'
 if ($PwshPath) {
     if (-not (Test-Path $PwshPath)) { throw "PowerShell 7 not found at '$PwshPath'." }
@@ -55,51 +52,23 @@ if (-not $Tenant -and $OrganizationTenants.Count -eq 0) {
     Write-Warning 'No -Tenant or -OrganizationTenants: jobs will be listed under their Microsoft 365 organization name.'
 }
 
-if ($ApiUrl -notmatch '^https://') {
-    Write-Warning 'ApiUrl is not HTTPS: the API key would be sent in clear text.'
+# Shared installer code: in the repo it's in ..\common, so copy the whole collectors folder
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    throw "BackupDashboard.Collector.psm1 not found. Copy the whole collectors folder, including common."
 }
+Import-Module $sharedModule -Force
 
-# Read the key as a SecureString so it isn't echoed to the console or kept in shell history
-$secure = Read-Host -AsSecureString 'API key (from: python manage.py create-key <name>)'
-$bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($secure)
-try { $apiKey = [Runtime.InteropServices.Marshal]::PtrToStringBSTR($bstr) }
-finally { [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr) }
-if (-not $apiKey.StartsWith('bdk_')) { throw "That doesn't look like a dashboard API key (expected 'bdk_...')." }
-
-# Config folder: SYSTEM + Administrators only (SIDs so this works on non-English Windows)
-New-Item -ItemType Directory -Path $DataDir -Force | Out-Null
-& icacls.exe $DataDir /inheritance:r /grant:r '*S-1-5-18:(OI)(CI)F' '*S-1-5-32-544:(OI)(CI)F' | Out-Null
-if ($LASTEXITCODE) { throw "icacls failed on $DataDir" }
-
-$config = [ordered]@{
-    ApiUrl              = $ApiUrl.TrimEnd('/')
-    ApiKey              = $apiKey
+$settings = [ordered]@{
     SourceSystem        = $SourceSystem
     LookbackHours       = $LookbackHours
     OrganizationTenants = $OrganizationTenants
 }
-if ($Tenant) { $config.Tenant = $Tenant }
-$config | ConvertTo-Json | Set-Content -Path $ConfigPath -Encoding UTF8
-
-New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
-$scriptPath = Join-Path $InstallDir 'Send-Vb365BackupStatus.ps1'
-Copy-Item -Path (Join-Path $PSScriptRoot 'Send-Vb365BackupStatus.ps1') -Destination $scriptPath -Force
-Unblock-File -Path $scriptPath
-
-$action = New-ScheduledTaskAction -Execute $Shell `
-    -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$scriptPath`""
-$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date).AddMinutes(1) `
-    -RepetitionInterval (New-TimeSpan -Minutes $IntervalMinutes)
-$principal = New-ScheduledTaskPrincipal -UserId 'S-1-5-18' -LogonType ServiceAccount -RunLevel Highest
-$settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 30) `
-    -MultipleInstances IgnoreNew -StartWhenAvailable
-Register-ScheduledTask -TaskName $TaskName -Action $action -Trigger $trigger -Principal $principal `
-    -Settings $settings -Description 'Sends Veeam Backup for Microsoft 365 results to the Backup Dashboard' -Force | Out-Null
-
-Write-Host "Installed. Config: $ConfigPath"
-Write-Host "Task '$TaskName' runs every $IntervalMinutes minutes as SYSTEM, using $Shell."
-Write-Host ''
-Write-Host 'Next steps:'
-Write-Host "  1. Preview what will be sent:   & '$Shell' -File '$scriptPath' -DryRun"
-Write-Host "  2. Backfill 30 days of history: & '$Shell' -File '$scriptPath' -LookbackHours 720"
-Write-Host "  3. Check the log:               Get-Content '$DataDir\vb365-collector.log' -Tail 20"
+if ($Tenant) { $settings.Tenant = $Tenant }
+Install-CollectorTask -Name 'vb365' -ScriptPath (Join-Path $PSScriptRoot 'Send-Vb365BackupStatus.ps1') `
+    -TaskName 'Backup Dashboard - VB365 collector' `
+    -TaskDescription 'Sends Veeam Backup for Microsoft 365 results to the Backup Dashboard' `
+    -Shell $Shell -ApiUrl $ApiUrl -IntervalMinutes $IntervalMinutes -InstallDir $InstallDir -Settings $settings
diff --git a/collectors/vb365/README.md b/collectors/vb365/README.md
index 9c005d4..2ab330e 100644
--- a/collectors/vb365/README.md
+++ b/collectors/vb365/README.md
@@ -27,7 +27,8 @@ one with `python manage.py delete-job <id>`.
    ```bash
    python manage.py create-key vb365-01
    ```
-2. Copy this folder to the server and run one of:
+2. Copy the whole `collectors` folder to the server (the installer needs `common`
+   as well as this folder), then from `collectors\vb365` run one of:
    ```powershell
    # VB365 server for one client
    .\Install-Vb365Collector.ps1 -ApiUrl https://backups.example.com -Tenant "Acme Corp"
@@ -52,7 +53,8 @@ one with `python manage.py delete-job <id>`.
    ```
 
 It can be installed alongside the other collectors: it uses its own config, state, log and task.
-Re-run the installer to change settings (including the organization mapping) or update the script.
+Re-run the installer to change settings (including the organization mapping) or update the script. It also installs
+`BackupDashboard.Collector.psm1`, the code shared by all collectors, next to the script.
 
 ## What it sends
 
diff --git a/collectors/vb365/Send-Vb365BackupStatus.ps1 b/collectors/vb365/Send-Vb365BackupStatus.ps1
index ce4b701..3f34945 100644
--- a/collectors/vb365/Send-Vb365BackupStatus.ps1
+++ b/collectors/vb365/Send-Vb365BackupStatus.ps1
@@ -41,61 +41,21 @@ param(
 
 $ErrorActionPreference = 'Stop'
 
-$DataDir = Split-Path -Parent $ConfigPath
-$LogPath = Join-Path $DataDir 'vb365-collector.log'
-$StatePath = Join-Path $DataDir 'vb365-collector.state.json'
-$MaxLogBytes = 5MB
+# Shared collector code: installed next to this script; in the repo, in ..\common
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    Write-Host "BackupDashboard.Collector.psm1 not found next to $PSCommandPath; re-run the installer."
+    exit 2
+}
+Import-Module $sharedModule -Force
+
 $Invariant = [Globalization.CultureInfo]::InvariantCulture
 
 # ---------- Helpers ----------
 
-function Write-Log {
-    param([string]$Message, [string]$Level = 'INFO')
-    $line = '{0} [{1}] {2}' -f (Get-Date).ToString('yyyy-MM-dd HH:mm:ss'), $Level, $Message
-    Write-Host $line
-    if ($DryRun) { return }
-    if ((Test-Path $LogPath) -and (Get-Item $LogPath).Length -gt $MaxLogBytes) {
-        Move-Item $LogPath "$LogPath.1" -Force
-    }
-    Add-Content -Path $LogPath -Value $line -Encoding UTF8
-}
-
-function Get-ErrorText($ErrorRecord) {
-    # Windows PowerShell puts the HTTP response body (e.g. the API's 422 explanation) here
-    if ($ErrorRecord.ErrorDetails -and $ErrorRecord.ErrorDetails.Message) {
-        return "$($ErrorRecord.Exception.Message) $($ErrorRecord.ErrorDetails.Message)"
-    }
-    return $ErrorRecord.Exception.Message
-}
-
-# The API needs an explicit UTC offset. DateTimeOffset keeps a Local/Unspecified time as local and a
-# Utc time as +00:00.
-function ConvertTo-IsoTime($Value) {
-    if ($null -eq $Value) { return $null }
-    $dt = [datetime]$Value
-    if ($dt.Year -le 1900) { return $null }  # "not set" (DateTime.MinValue and friends)
-    return ([DateTimeOffset]$dt).ToString("yyyy-MM-dd'T'HH:mm:sszzz", $Invariant)
-}
-
-# First property of $Object, out of $Names, that exists and isn't empty. The VB365 object model isn't
-# fully documented, so reads go through this rather than assuming one spelling.
-function Get-FirstValue($Object, [string[]]$Names) {
-    if ($null -eq $Object) { return $null }
-    foreach ($name in $Names) {
-        try {
-            $prop = $Object.PSObject.Properties[$name]
-            if (-not $prop) { continue }
-            $value = $prop.Value
-            # Check emptiness by type: casting to [string] would make a one-item list of objects ''
-            if ($null -eq $value) { continue }
-            if ($value -is [string] -and $value -eq '') { continue }
-            if ($value -is [Collections.ICollection] -and $value.Count -eq 0) { continue }
-            return $value
-        } catch { }
-    }
-    return $null
-}
-
 function Import-Vb365 {
     if (Get-Command Get-VBOJob -ErrorAction SilentlyContinue) { return }  # already loaded
     if (Get-Module -ListAvailable -Name Veeam.Archiver.PowerShell) {
@@ -245,48 +205,15 @@ function ConvertTo-Run($Session, $Job, [string]$JobKind) {
     return $run
 }
 
-function Send-Report($Body) {
-    $json = $Body | ConvertTo-Json -Depth 6 -Compress
-    if ($DryRun) {
-        Write-Host $json
-        return
-    }
-    # Send bytes: Windows PowerShell would otherwise encode a string body as Latin-1
-    $params = @{
-        Uri         = "$($Config.ApiUrl.TrimEnd('/'))/api/v1/ingest"
-        Method      = 'Post'
-        Headers     = @{ Authorization = "Bearer $($Config.ApiKey)" }
-        ContentType = 'application/json; charset=utf-8'
-        Body        = [Text.Encoding]::UTF8.GetBytes($json)
-        TimeoutSec  = 30
-    }
-    Invoke-RestMethod @params | Out-Null
-}
-
 # ---------- Main ----------
 
 try {
-    $Config = Get-Content -Path $ConfigPath -Raw | ConvertFrom-Json
-    foreach ($key in 'ApiUrl', 'ApiKey') {
-        if (-not $Config.$key) { throw "Config $ConfigPath is missing '$key'" }
-    }
+    $Config = Initialize-Collector -Name 'vb365' -ConfigPath $ConfigPath -LookbackHours $LookbackHours -DryRun:$DryRun -RequiredKeys 'ApiUrl', 'ApiKey'
     $SourceSystem = if ($Config.SourceSystem) { [string]$Config.SourceSystem } else { 'Veeam Backup for M365' }
-    if ($LookbackHours -le 0) {
-        $LookbackHours = if ($Config.LookbackHours) { [int]$Config.LookbackHours } else { 48 }
-    }
-
-    # Windows PowerShell 5.1 may default to TLS 1.0
-    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+    $LookbackHours = $Config.LookbackHours
 
     Import-Vb365
 
-    # Session ID -> start time (Unix seconds), for sessions already delivered in their final state
-    $sent = @{}
-    if (Test-Path $StatePath) {
-        $saved = Get-Content -Path $StatePath -Raw | ConvertFrom-Json
-        if ($saved) { foreach ($p in $saved.PSObject.Properties) { $sent[$p.Name] = [long]$p.Value } }
-    }
-
     $since = (Get-Date).AddHours(-$LookbackHours)
 
     # (job, kind, sessions) for backup jobs, plus backup copy jobs where the cmdlets exist
@@ -315,7 +242,6 @@ try {
 }
 
 $failures = 0
-$runsSent = 0
 foreach ($item in $work) {
     $job = $item.Job
     $tenant = Get-TenantForJob $job
@@ -326,47 +252,27 @@ foreach ($item in $work) {
         next_run_at = Get-NextRun $job
     }
     $pending = @($item.Sessions |
-        Where-Object { $_ -and -not $sent.ContainsKey([string](Get-FirstValue $_ @('Id', 'SessionId'))) } |
+        Where-Object { $_ -and -not (Test-RunSent ([string](Get-FirstValue $_ @('Id', 'SessionId')))) } |
         Sort-Object { Get-Time $_ 'CreationTime' })
 
     try {
         if ($pending.Count -eq 0) {
             # Keep next_run_at fresh even when nothing new ran
-            Send-Report ([ordered]@{ tenant = $tenant; source_system = $SourceSystem; job = $jobInfo })
+            Send-JobReport -Tenant $tenant -SourceSystem $SourceSystem -Job $jobInfo
         }
         foreach ($session in $pending) {
             $run = ConvertTo-Run $session $job $item.Kind
-            Send-Report ([ordered]@{ tenant = $tenant; source_system = $SourceSystem; job = $jobInfo; run = $run })
-            $runsSent++
-            if ($run.status -ne 'running') {
-                $sent[$run.external_id] = ([DateTimeOffset](Get-Time $session 'CreationTime')).ToUnixTimeSeconds()
-            }
+            Send-JobReport -Tenant $tenant -SourceSystem $SourceSystem -Job $jobInfo -Run $run -SentKey $run.external_id -StartedAt ((Get-Time $session 'CreationTime'))
         }
     } catch {
         $failures++
         Write-Log "Failed to report job '$($job.Name)': $(Get-ErrorText $_)" 'ERROR'
-        $httpStatus = 0
-        try { $httpStatus = [int]$_.Exception.Response.StatusCode } catch { }
-        if ($httpStatus -eq 401) {
+        if (Test-AuthRejected $_) {
             Write-Log 'API key rejected; check ApiKey in the config. Stopping.' 'ERROR'
             break
         }
     }
 }
 
-if (-not $DryRun) {
-    # Forget sessions that have aged out of the lookback window (plus a day of slack)
-    $cutoff = [DateTimeOffset]::Now.AddHours(-$LookbackHours - 24).ToUnixTimeSeconds()
-    $keep = [ordered]@{}
-    foreach ($id in $sent.Keys) {
-        if ($sent[$id] -ge $cutoff) { $keep[$id] = $sent[$id] }
-    }
-    try {
-        $keep | ConvertTo-Json -Compress | Set-Content -Path $StatePath -Encoding UTF8
-    } catch {
-        Write-Log "Couldn't save state file: $(Get-ErrorText $_)" 'WARN'
-    }
-}
-
-Write-Log ("Reported {0} jobs, {1} runs, {2} failures" -f $work.Count, $runsSent, $failures)
-if ($failures) { exit 1 }
+$exitCode = Complete-Collector -JobCount $work.Count -Failures $failures
+if ($exitCode) { exit $exitCode }
diff --git a/collectors/veeam/Install-VeeamCollector.ps1 b/collectors/veeam/Install-VeeamCollector.ps1
index e7ddb24..b57ed41 100644
--- a/collectors/veeam/Install-VeeamCollector.ps1
+++ b/collectors/veeam/Install-VeeamCollector.ps1
@@ -30,9 +30,6 @@ param(
 )
 
 $ErrorActionPreference = 'Stop'
-$TaskName = 'Backup Dashboard - Veeam collector'
-$DataDir = Join-Path $env:ProgramData 'BackupDashboard'
-$ConfigPath = Join-Path $DataDir 'veeam-collector.json'
 
 # Find PowerShell 7 before changing anything, so a missing install fails cleanly
 if (-not $PwshPath) {
@@ -54,49 +51,18 @@ if ($LASTEXITCODE -or ($pwshMajor -as [int]) -lt 7) {
     throw "'$PwshPath' isn't a working PowerShell 7 (reported '$pwshVersion')."
 }
 
-if ($ApiUrl -notmatch '^https://') {
-    Write-Warning 'ApiUrl is not HTTPS: the API key would be sent in clear text.'
+# Shared installer code: in the repo it's in ..\common, so copy the whole collectors folder
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    throw "BackupDashboard.Collector.psm1 not found. Copy the whole collectors folder, including common."
 }
+Import-Module $sharedModule -Force
 
-# Read the key as a SecureString so it isn't echoed to the console or kept in shell history
-$secure = Read-Host -AsSecureString 'API key (from: python manage.py create-key <name>)'
-$bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($secure)
-try { $apiKey = [Runtime.InteropServices.Marshal]::PtrToStringBSTR($bstr) }
-finally { [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr) }
-if (-not $apiKey.StartsWith('bdk_')) { throw "That doesn't look like a dashboard API key (expected 'bdk_...')." }
-
-# Config folder: SYSTEM + Administrators only (SIDs so this works on non-English Windows)
-New-Item -ItemType Directory -Path $DataDir -Force | Out-Null
-& icacls.exe $DataDir /inheritance:r /grant:r '*S-1-5-18:(OI)(CI)F' '*S-1-5-32-544:(OI)(CI)F' | Out-Null
-if ($LASTEXITCODE) { throw "icacls failed on $DataDir" }
-
-[ordered]@{
-    ApiUrl        = $ApiUrl.TrimEnd('/')
-    ApiKey        = $apiKey
-    Tenant        = $Tenant
-    SourceSystem  = $SourceSystem
-    LookbackHours = $LookbackHours
-} | ConvertTo-Json | Set-Content -Path $ConfigPath -Encoding UTF8
-
-New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
-$scriptPath = Join-Path $InstallDir 'Send-VeeamBackupStatus.ps1'
-Copy-Item -Path (Join-Path $PSScriptRoot 'Send-VeeamBackupStatus.ps1') -Destination $scriptPath -Force
-Unblock-File -Path $scriptPath
-
-$action = New-ScheduledTaskAction -Execute $PwshPath `
-    -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$scriptPath`""
-$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date).AddMinutes(1) `
-    -RepetitionInterval (New-TimeSpan -Minutes $IntervalMinutes)
-$principal = New-ScheduledTaskPrincipal -UserId 'S-1-5-18' -LogonType ServiceAccount -RunLevel Highest
-$settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 30) `
-    -MultipleInstances IgnoreNew -StartWhenAvailable
-Register-ScheduledTask -TaskName $TaskName -Action $action -Trigger $trigger -Principal $principal `
-    -Settings $settings -Description 'Sends Veeam job results to the Backup Dashboard' -Force | Out-Null
-
-Write-Host "Installed. Config: $ConfigPath"
-Write-Host "Task '$TaskName' runs every $IntervalMinutes minutes as SYSTEM, using PowerShell $pwshVersion ($PwshPath)."
-Write-Host ''
-Write-Host 'Next steps:'
-Write-Host "  1. Preview what will be sent:   & '$PwshPath' -File '$scriptPath' -DryRun"
-Write-Host "  2. Backfill 30 days of history: & '$PwshPath' -File '$scriptPath' -LookbackHours 720"
-Write-Host "  3. Check the log:               Get-Content '$DataDir\veeam-collector.log' -Tail 20"
+$settings = [ordered]@{ Tenant = $Tenant; SourceSystem = $SourceSystem; LookbackHours = $LookbackHours }
+Install-CollectorTask -Name 'veeam' -ScriptPath (Join-Path $PSScriptRoot 'Send-VeeamBackupStatus.ps1') `
+    -TaskName 'Backup Dashboard - Veeam collector' `
+    -TaskDescription 'Sends Veeam job results to the Backup Dashboard' `
+    -Shell $PwshPath -ApiUrl $ApiUrl -IntervalMinutes $IntervalMinutes -InstallDir $InstallDir -Settings $settings
diff --git a/collectors/veeam/README.md b/collectors/veeam/README.md
index 5b3dede..52162a7 100644
--- a/collectors/veeam/README.md
+++ b/collectors/veeam/README.md
@@ -13,7 +13,8 @@ account can't run it. The installer checks for this before changing anything.
    ```bash
    python manage.py create-key veeam-acme
    ```
-2. Copy this folder to the VBR server and run, from PowerShell 7 (`pwsh`):
+2. Copy the whole `collectors` folder to the VBR server (the installer needs `common`
+   as well as this folder), then from `collectors\veeam` run, from PowerShell 7 (`pwsh`):
    ```powershell
    .\Install-VeeamCollector.ps1 -ApiUrl https://backups.example.com -Tenant "Acme Corp"
    ```
@@ -29,7 +30,8 @@ account can't run it. The installer checks for this before changing anything.
    & 'C:\Program Files\BackupDashboard\Send-VeeamBackupStatus.ps1' -LookbackHours 720
    ```
 
-Re-run the installer to change settings or update the script. To remove the collector,
+Re-run the installer to change settings or update the script. It also installs
+`BackupDashboard.Collector.psm1`, the code shared by all collectors, next to the script. To remove the collector,
 delete the scheduled task and both `BackupDashboard` folders.
 
 ## What it sends
diff --git a/collectors/veeam/Send-VeeamBackupStatus.ps1 b/collectors/veeam/Send-VeeamBackupStatus.ps1
index 36c6dcb..c216c45 100644
--- a/collectors/veeam/Send-VeeamBackupStatus.ps1
+++ b/collectors/veeam/Send-VeeamBackupStatus.ps1
@@ -37,42 +37,19 @@ param(
 
 $ErrorActionPreference = 'Stop'
 
-$DataDir = Split-Path -Parent $ConfigPath
-$LogPath = Join-Path $DataDir 'veeam-collector.log'
-$StatePath = Join-Path $DataDir 'veeam-collector.state.json'
-$MaxLogBytes = 5MB
-$Invariant = [Globalization.CultureInfo]::InvariantCulture
+# Shared collector code: installed next to this script; in the repo, in ..\common
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    Write-Host "BackupDashboard.Collector.psm1 not found next to $PSCommandPath; re-run the installer."
+    exit 2
+}
+Import-Module $sharedModule -Force
 
 # ---------- Helpers ----------
 
-function Write-Log {
-    param([string]$Message, [string]$Level = 'INFO')
-    $line = '{0} [{1}] {2}' -f (Get-Date).ToString('yyyy-MM-dd HH:mm:ss'), $Level, $Message
-    Write-Host $line
-    if ($DryRun) { return }
-    if ((Test-Path $LogPath) -and (Get-Item $LogPath).Length -gt $MaxLogBytes) {
-        Move-Item $LogPath "$LogPath.1" -Force
-    }
-    Add-Content -Path $LogPath -Value $line -Encoding UTF8
-}
-
-function Get-ErrorText($ErrorRecord) {
-    # Windows PowerShell puts the HTTP response body (e.g. the API's 422 explanation) here
-    if ($ErrorRecord.ErrorDetails -and $ErrorRecord.ErrorDetails.Message) {
-        return "$($ErrorRecord.Exception.Message) $($ErrorRecord.ErrorDetails.Message)"
-    }
-    return $ErrorRecord.Exception.Message
-}
-
-# The API needs an explicit UTC offset. Veeam returns local times, often with Kind=Unspecified,
-# which DateTimeOffset treats as local, exactly what we want.
-function ConvertTo-IsoTime($Value) {
-    if ($null -eq $Value) { return $null }
-    $dt = [datetime]$Value
-    if ($dt.Year -le 1900) { return $null }  # Veeam's "not set" value (e.g. EndTime while running)
-    return ([DateTimeOffset]$dt).ToString("yyyy-MM-dd'T'HH:mm:sszzz", $Invariant)
-}
-
 function Import-Veeam {
     if (Get-Command Get-VBRJob -ErrorAction SilentlyContinue) { return }  # already loaded
     if (Get-Module -ListAvailable -Name Veeam.Backup.PowerShell) {
@@ -217,51 +194,15 @@ function ConvertTo-Run($Session, $Job) {
     return $run
 }
 
-function Send-Report($Body) {
-    $json = $Body | ConvertTo-Json -Depth 6 -Compress
-    if ($DryRun) {
-        Write-Host $json
-        return
-    }
-    # Send bytes: Windows PowerShell would otherwise encode a string body as Latin-1,
-    # mangling non-ASCII job names (e.g. en dashes).
-    $params = @{
-        Uri         = "$($Config.ApiUrl.TrimEnd('/'))/api/v1/ingest"
-        Method      = 'Post'
-        Headers     = @{ Authorization = "Bearer $($Config.ApiKey)" }
-        ContentType = 'application/json; charset=utf-8'
-        Body        = [Text.Encoding]::UTF8.GetBytes($json)
-        TimeoutSec  = 30
-    }
-    Invoke-RestMethod @params | Out-Null
-}
-
 # ---------- Main ----------
 
 try {
-    $Config = Get-Content -Path $ConfigPath -Raw | ConvertFrom-Json
-    foreach ($key in 'ApiUrl', 'ApiKey', 'Tenant') {
-        if (-not $Config.$key) { throw "Config $ConfigPath is missing '$key'" }
-    }
+    $Config = Initialize-Collector -Name 'veeam' -ConfigPath $ConfigPath -LookbackHours $LookbackHours -DryRun:$DryRun
     $SourceSystem = if ($Config.SourceSystem) { [string]$Config.SourceSystem } else { 'Veeam B&R' }
-    if ($LookbackHours -le 0) {
-        $LookbackHours = if ($Config.LookbackHours) { [int]$Config.LookbackHours } else { 48 }
-    }
-
-    # Windows PowerShell 5.1 may default to TLS 1.0
-    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+    $LookbackHours = $Config.LookbackHours
 
     Import-Veeam
 
-    # Session ID -> start time (Unix seconds), for sessions already delivered in their final state.
-    # Numbers rather than ISO strings: PowerShell 7's ConvertFrom-Json turns date strings into
-    # DateTimes and loses the offset.
-    $sent = @{}
-    if (Test-Path $StatePath) {
-        $saved = Get-Content -Path $StatePath -Raw | ConvertFrom-Json
-        if ($saved) { foreach ($p in $saved.PSObject.Properties) { $sent[$p.Name] = [long]$p.Value } }
-    }
-
     $since = (Get-Date).AddHours(-$LookbackHours)
     $jobs = @(Get-VBRJob -WarningAction SilentlyContinue)
 
@@ -288,7 +229,6 @@ try {
 }
 
 $failures = 0
-$runsSent = 0
 foreach ($job in $jobs) {
     $jobInfo = [ordered]@{
         external_id = $job.Id.ToString()
@@ -299,48 +239,28 @@ foreach ($job in $jobs) {
     $pending = @()
     if ($sessionsByJob.ContainsKey($jobInfo.external_id)) {
         $pending = @($sessionsByJob[$jobInfo.external_id] |
-            Where-Object { -not $sent.ContainsKey($_.Id.ToString()) } |
+            Where-Object { -not (Test-RunSent ($_.Id.ToString())) } |
             Sort-Object CreationTime)
     }
 
     try {
         if ($pending.Count -eq 0) {
             # Keep next_run_at fresh even when nothing new ran
-            Send-Report ([ordered]@{ tenant = $Config.Tenant; source_system = $SourceSystem; job = $jobInfo })
+            Send-JobReport -Tenant $Config.Tenant -SourceSystem $SourceSystem -Job $jobInfo
         }
         foreach ($session in $pending) {
             $run = ConvertTo-Run $session $job
-            Send-Report ([ordered]@{ tenant = $Config.Tenant; source_system = $SourceSystem; job = $jobInfo; run = $run })
-            $runsSent++
-            if ($run.status -ne 'running') {
-                $sent[$run.external_id] = ([DateTimeOffset][datetime]$session.CreationTime).ToUnixTimeSeconds()
-            }
+            Send-JobReport -Tenant $Config.Tenant -SourceSystem $SourceSystem -Job $jobInfo -Run $run -SentKey $run.external_id -StartedAt ([datetime]$session.CreationTime)
         }
     } catch {
         $failures++
         Write-Log "Failed to report job '$($job.Name)': $(Get-ErrorText $_)" 'ERROR'
-        $httpStatus = 0
-        try { $httpStatus = [int]$_.Exception.Response.StatusCode } catch { }
-        if ($httpStatus -eq 401) {
+        if (Test-AuthRejected $_) {
             Write-Log 'API key rejected; check ApiKey in the config. Stopping.' 'ERROR'
             break
         }
     }
 }
 
-if (-not $DryRun) {
-    # Forget sessions that have aged out of the lookback window (plus a day of slack)
-    $cutoff = [DateTimeOffset]::Now.AddHours(-$LookbackHours - 24).ToUnixTimeSeconds()
-    $keep = [ordered]@{}
-    foreach ($id in $sent.Keys) {
-        if ($sent[$id] -ge $cutoff) { $keep[$id] = $sent[$id] }
-    }
-    try {
-        $keep | ConvertTo-Json -Compress | Set-Content -Path $StatePath -Encoding UTF8
-    } catch {
-        Write-Log "Couldn't save state file: $(Get-ErrorText $_)" 'WARN'
-    }
-}
-
-Write-Log ("Reported {0} jobs, {1} runs, {2} failures" -f $jobs.Count, $runsSent, $failures)
-if ($failures) { exit 1 }
+$exitCode = Complete-Collector -JobCount $jobs.Count -Failures $failures
+if ($exitCode) { exit $exitCode }
diff --git a/collectors/wsb/Install-WsbCollector.ps1 b/collectors/wsb/Install-WsbCollector.ps1
index 963d74c..4bb2938 100644
--- a/collectors/wsb/Install-WsbCollector.ps1
+++ b/collectors/wsb/Install-WsbCollector.ps1
@@ -29,9 +29,6 @@ param(
 )
 
 $ErrorActionPreference = 'Stop'
-$TaskName = 'Backup Dashboard - WSB collector'
-$DataDir = Join-Path $env:ProgramData 'BackupDashboard'
-$ConfigPath = Join-Path $DataDir 'wsb-collector.json'
 $WindowsPowerShell = Join-Path $env:SystemRoot 'System32\WindowsPowerShell\v1.0\powershell.exe'
 
 # Check Windows Server Backup is here before changing anything
@@ -39,51 +36,19 @@ if (-not (Get-Module -ListAvailable -Name WindowsServerBackup)) {
     throw 'The WindowsServerBackup PowerShell module is not available. Install the Windows Server Backup feature (Install-WindowsFeature Windows-Server-Backup).'
 }
 
-if ($ApiUrl -notmatch '^https://') {
-    Write-Warning 'ApiUrl is not HTTPS: the API key would be sent in clear text.'
+# Shared installer code: in the repo it's in ..\common, so copy the whole collectors folder
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    throw "BackupDashboard.Collector.psm1 not found. Copy the whole collectors folder, including common."
 }
+Import-Module $sharedModule -Force
 
-# Read the key as a SecureString so it isn't echoed to the console or kept in shell history
-$secure = Read-Host -AsSecureString 'API key (from: python manage.py create-key <name>)'
-$bstr = [Runtime.InteropServices.Marshal]::SecureStringToBSTR($secure)
-try { $apiKey = [Runtime.InteropServices.Marshal]::PtrToStringBSTR($bstr) }
-finally { [Runtime.InteropServices.Marshal]::ZeroFreeBSTR($bstr) }
-if (-not $apiKey.StartsWith('bdk_')) { throw "That doesn't look like a dashboard API key (expected 'bdk_...')." }
-
-# Config folder: SYSTEM + Administrators only (SIDs so this works on non-English Windows)
-New-Item -ItemType Directory -Path $DataDir -Force | Out-Null
-& icacls.exe $DataDir /inheritance:r /grant:r '*S-1-5-18:(OI)(CI)F' '*S-1-5-32-544:(OI)(CI)F' | Out-Null
-if ($LASTEXITCODE) { throw "icacls failed on $DataDir" }
-
-$config = [ordered]@{
-    ApiUrl        = $ApiUrl.TrimEnd('/')
-    ApiKey        = $apiKey
-    Tenant        = $Tenant
-    SourceSystem  = $SourceSystem
-    LookbackHours = $LookbackHours
-}
-if ($JobName) { $config.JobName = $JobName }
-$config | ConvertTo-Json | Set-Content -Path $ConfigPath -Encoding UTF8
-
-New-Item -ItemType Directory -Path $InstallDir -Force | Out-Null
-$scriptPath = Join-Path $InstallDir 'Send-WsbBackupStatus.ps1'
-Copy-Item -Path (Join-Path $PSScriptRoot 'Send-WsbBackupStatus.ps1') -Destination $scriptPath -Force
-Unblock-File -Path $scriptPath
-
-$action = New-ScheduledTaskAction -Execute $WindowsPowerShell `
-    -Argument "-NoProfile -NonInteractive -ExecutionPolicy Bypass -File `"$scriptPath`""
-$trigger = New-ScheduledTaskTrigger -Once -At (Get-Date).AddMinutes(1) `
-    -RepetitionInterval (New-TimeSpan -Minutes $IntervalMinutes)
-$principal = New-ScheduledTaskPrincipal -UserId 'S-1-5-18' -LogonType ServiceAccount -RunLevel Highest
-$settings = New-ScheduledTaskSettingsSet -ExecutionTimeLimit (New-TimeSpan -Minutes 30) `
-    -MultipleInstances IgnoreNew -StartWhenAvailable
-Register-ScheduledTask -TaskName $TaskName -Action $action -Trigger $trigger -Principal $principal `
-    -Settings $settings -Description 'Sends Windows Server Backup results to the Backup Dashboard' -Force | Out-Null
-
-Write-Host "Installed. Config: $ConfigPath"
-Write-Host "Task '$TaskName' runs every $IntervalMinutes minutes as SYSTEM, using Windows PowerShell."
-Write-Host ''
-Write-Host 'Next steps:'
-Write-Host "  1. Preview what will be sent:   & '$WindowsPowerShell' -File '$scriptPath' -DryRun"
-Write-Host "  2. Backfill 30 days of history: & '$WindowsPowerShell' -File '$scriptPath' -LookbackHours 720"
-Write-Host "  3. Check the log:               Get-Content '$DataDir\wsb-collector.log' -Tail 20"
+$settings = [ordered]@{ Tenant = $Tenant; SourceSystem = $SourceSystem; LookbackHours = $LookbackHours }
+if ($JobName) { $settings.JobName = $JobName }
+Install-CollectorTask -Name 'wsb' -ScriptPath (Join-Path $PSScriptRoot 'Send-WsbBackupStatus.ps1') `
+    -TaskName 'Backup Dashboard - WSB collector' `
+    -TaskDescription 'Sends Windows Server Backup results to the Backup Dashboard' `
+    -Shell $WindowsPowerShell -ApiUrl $ApiUrl -IntervalMinutes $IntervalMinutes -InstallDir $InstallDir -Settings $settings
diff --git a/collectors/wsb/README.md b/collectors/wsb/README.md
index c31e699..e983d7f 100644
--- a/collectors/wsb/README.md
+++ b/collectors/wsb/README.md
@@ -19,7 +19,8 @@ Requires the Windows Server Backup feature with its PowerShell module
    ```bash
    python manage.py create-key wsb-acme-dc01
    ```
-2. Copy this folder to the server and run:
+2. Copy the whole `collectors` folder to the server (the installer needs `common`
+   as well as this folder), then from `collectors\wsb` run:
    ```powershell
    .\Install-WsbCollector.ps1 -ApiUrl https://backups.example.com -Tenant "Acme Corp"
    ```
@@ -35,7 +36,8 @@ Requires the Windows Server Backup feature with its PowerShell module
    ```
 
 It can be installed alongside the other collectors: it uses its own config, state, log and task.
-Re-run the installer to change settings or update the script.
+Re-run the installer to change settings or update the script. It also installs
+`BackupDashboard.Collector.psm1`, the code shared by all collectors, next to the script.
 
 ## What it sends
 
diff --git a/collectors/wsb/Send-WsbBackupStatus.ps1 b/collectors/wsb/Send-WsbBackupStatus.ps1
index 89f87d3..c6b76c3 100644
--- a/collectors/wsb/Send-WsbBackupStatus.ps1
+++ b/collectors/wsb/Send-WsbBackupStatus.ps1
@@ -40,64 +40,23 @@ param(
 
 $ErrorActionPreference = 'Stop'
 
-$DataDir = Split-Path -Parent $ConfigPath
-$LogPath = Join-Path $DataDir 'wsb-collector.log'
-$StatePath = Join-Path $DataDir 'wsb-collector.state.json'
-$MaxLogBytes = 5MB
+# Shared collector code: installed next to this script; in the repo, in ..\common
+$sharedModule = @(
+    (Join-Path $PSScriptRoot 'BackupDashboard.Collector.psm1'),
+    (Join-Path (Join-Path (Join-Path $PSScriptRoot '..') 'common') 'BackupDashboard.Collector.psm1')
+) | Where-Object { Test-Path $_ } | Select-Object -First 1
+if (-not $sharedModule) {
+    Write-Host "BackupDashboard.Collector.psm1 not found next to $PSCommandPath; re-run the installer."
+    exit 2
+}
+Import-Module $sharedModule -Force
+
 # Get-WBJob -Previous accepts at most 100. That covers a 30-day backfill at up to 3 backups a day;
 # servers backing up more often only get their latest 100 runs backfilled.
 $MaxPreviousJobs = 100
-$Invariant = [Globalization.CultureInfo]::InvariantCulture
 
 # ---------- Helpers ----------
 
-function Write-Log {
-    param([string]$Message, [string]$Level = 'INFO')
-    $line = '{0} [{1}] {2}' -f (Get-Date).ToString('yyyy-MM-dd HH:mm:ss'), $Level, $Message
-    Write-Host $line
-    if ($DryRun) { return }
-    if ((Test-Path $LogPath) -and (Get-Item $LogPath).Length -gt $MaxLogBytes) {
-        Move-Item $LogPath "$LogPath.1" -Force
-    }
-    Add-Content -Path $LogPath -Value $line -Encoding UTF8
-}
-
-function Get-ErrorText($ErrorRecord) {
-    # Windows PowerShell puts the HTTP response body (e.g. the API's 422 explanation) here
-    if ($ErrorRecord.ErrorDetails -and $ErrorRecord.ErrorDetails.Message) {
-        return "$($ErrorRecord.Exception.Message) $($ErrorRecord.ErrorDetails.Message)"
-    }
-    return $ErrorRecord.Exception.Message
-}
-
-# The API needs an explicit UTC offset. DateTimeOffset keeps a Local/Unspecified time as local and a
-# Utc time as +00:00.
-function ConvertTo-IsoTime($Value) {
-    if ($null -eq $Value) { return $null }
-    $dt = [datetime]$Value
-    if ($dt.Year -le 1900) { return $null }  # "not set" (DateTime.MinValue and friends)
-    return ([DateTimeOffset]$dt).ToString("yyyy-MM-dd'T'HH:mm:sszzz", $Invariant)
-}
-
-# First property of $Object, out of $Names, that exists and isn't empty. The WSB object model isn't
-# fully documented, so reads go through this rather than assuming one spelling.
-function Get-FirstValue($Object, [string[]]$Names) {
-    if ($null -eq $Object) { return $null }
-    foreach ($name in $Names) {
-        try {
-            $prop = $Object.PSObject.Properties[$name]
-            if (-not $prop) { continue }
-            $value = $prop.Value
-            # Check emptiness by type: casting to [string] would make a one-item list of objects ''
-            if ($null -eq $value) { continue }
-            if ($value -is [string] -and $value -eq '') { continue }
-            if ($value -is [Collections.ICollection] -and $value.Count -eq 0) { continue }
-            return $value
-        } catch { }
-    }
-    return $null
-}
-
 function Import-Wsb {
     if (Get-Command Get-WBJob -ErrorAction SilentlyContinue) { return }  # already loaded
     # Present only when the Windows Server Backup feature (with its command-line tools) is installed
@@ -288,49 +247,16 @@ function Get-NextRun {
     }
 }
 
-function Send-Report($Body) {
-    $json = $Body | ConvertTo-Json -Depth 6 -Compress
-    if ($DryRun) {
-        Write-Host $json
-        return
-    }
-    # Send bytes: Windows PowerShell would otherwise encode a string body as Latin-1
-    $params = @{
-        Uri         = "$($Config.ApiUrl.TrimEnd('/'))/api/v1/ingest"
-        Method      = 'Post'
-        Headers     = @{ Authorization = "Bearer $($Config.ApiKey)" }
-        ContentType = 'application/json; charset=utf-8'
-        Body        = [Text.Encoding]::UTF8.GetBytes($json)
-        TimeoutSec  = 30
-    }
-    Invoke-RestMethod @params | Out-Null
-}
-
 # ---------- Main ----------
 
 try {
-    $Config = Get-Content -Path $ConfigPath -Raw | ConvertFrom-Json
-    foreach ($key in 'ApiUrl', 'ApiKey', 'Tenant') {
-        if (-not $Config.$key) { throw "Config $ConfigPath is missing '$key'" }
-    }
+    $Config = Initialize-Collector -Name 'wsb' -ConfigPath $ConfigPath -LookbackHours $LookbackHours -DryRun:$DryRun
     $SourceSystem = if ($Config.SourceSystem) { [string]$Config.SourceSystem } else { 'Windows Server Backup' }
     $JobName = if ($Config.JobName) { [string]$Config.JobName } else { "$env:COMPUTERNAME - Windows Server Backup" }
-    if ($LookbackHours -le 0) {
-        $LookbackHours = if ($Config.LookbackHours) { [int]$Config.LookbackHours } else { 48 }
-    }
-
-    # Windows PowerShell 5.1 may default to TLS 1.0
-    [Net.ServicePointManager]::SecurityProtocol = [Net.ServicePointManager]::SecurityProtocol -bor [Net.SecurityProtocolType]::Tls12
+    $LookbackHours = $Config.LookbackHours
 
     Import-Wsb
 
-    # Run start time (ISO, as sent) -> Unix seconds, for runs already delivered in their final state
-    $sent = @{}
-    if (Test-Path $StatePath) {
-        $saved = Get-Content -Path $StatePath -Raw | ConvertFrom-Json
-        if ($saved) { foreach ($p in $saved.PSObject.Properties) { $sent[$p.Name] = [long]$p.Value } }
-    }
-
     $since = (Get-Date).AddHours(-$LookbackHours)
     # Get-WBJob with no arguments returns the job in progress (if any); -Previous lists finished ones
     $jobs = @(@(Get-WBJob) + @(Get-WBJob -Previous $MaxPreviousJobs) | Where-Object {
@@ -342,7 +268,7 @@ try {
         if ($start -lt $since) { continue }
         $byStart[(ConvertTo-IsoTime $start)] = $job  # a job in both lists: the finished entry (later) wins
     }
-    $pending = @($byStart.Keys | Sort-Object | Where-Object { -not $sent.ContainsKey($_) } |
+    $pending = @($byStart.Keys | Sort-Object | Where-Object { -not (Test-RunSent ($_)) } |
         ForEach-Object { $byStart[$_] })
 
     $jobInfo = [ordered]@{
@@ -358,38 +284,19 @@ try {
 }
 
 $failures = 0
-$runsSent = 0
 try {
     if ($pending.Count -eq 0) {
         # Keep next_run_at fresh even when nothing new ran
-        Send-Report ([ordered]@{ tenant = $Config.Tenant; source_system = $SourceSystem; job = $jobInfo })
+        Send-JobReport -Tenant $Config.Tenant -SourceSystem $SourceSystem -Job $jobInfo
     }
     foreach ($job in $pending) {
         $run = ConvertTo-Run $job
-        Send-Report ([ordered]@{ tenant = $Config.Tenant; source_system = $SourceSystem; job = $jobInfo; run = $run })
-        $runsSent++
-        if ($run.status -ne 'running') {
-            $sent[$run.started_at] = ([DateTimeOffset](Get-JobTime $job 'StartTime')).ToUnixTimeSeconds()
-        }
+        Send-JobReport -Tenant $Config.Tenant -SourceSystem $SourceSystem -Job $jobInfo -Run $run -SentKey $run.started_at -StartedAt ((Get-JobTime $job 'StartTime'))
     }
 } catch {
     $failures++
     Write-Log "Failed to report: $(Get-ErrorText $_)" 'ERROR'
 }
 
-if (-not $DryRun) {
-    # Forget runs that have aged out of the lookback window (plus a day of slack)
-    $cutoff = [DateTimeOffset]::Now.AddHours(-$LookbackHours - 24).ToUnixTimeSeconds()
-    $keep = [ordered]@{}
-    foreach ($key in $sent.Keys) {
-        if ($sent[$key] -ge $cutoff) { $keep[$key] = $sent[$key] }
-    }
-    try {
-        $keep | ConvertTo-Json -Compress | Set-Content -Path $StatePath -Encoding UTF8
-    } catch {
-        Write-Log "Couldn't save state file: $(Get-ErrorText $_)" 'WARN'
-    }
-}
-
-Write-Log ("Reported {0} runs, {1} failures" -f $runsSent, $failures)
-if ($failures) { exit 1 }
+$exitCode = Complete-Collector -Failures $failures
+if ($exitCode) { exit $exitCode }