PowerShell Webhook Voice Alerts: Invoke-RestMethod for Phone Call Notifications

PowerShell is the most powerful tool available to Windows system administrators. Almost anything can be scripted — service checks, disk monitoring, Event Log parsing, scheduled tasks. But the alerts these scripts produce usually go to email or a Teams channel. If nobody is watching at night, the same problem remains.

Calling the Alertalk webhook from PowerShell is a single code block. Any script running on Windows can be turned into a voice alert.

How to Send a Webhook from PowerShell?

PowerShell uses the Invoke-RestMethod cmdlet to send HTTP POST requests. The structure needed to call the Alertalk webhook is as follows:

$webhookUrl = "https://tr.alertalk.net/webhook/receive"
$webhookKey = "your-alertalk-key-here"

$body = @{
    phone_number  = "5XXXXXXXXX"
    error_message = "Your alert message here"
} | ConvertTo-Json

Invoke-RestMethod -Uri $webhookUrl `
    -Method POST `
    -Headers @{ "X-Webhook-Key" = $webhookKey; "Content-Type" = "application/json" } `
    -Body $body

That is all that is needed to trigger an alert.

Service Status Monitoring

A script that triggers a phone call when a Windows service stops:

$webhookUrl = "https://tr.alertalk.net/webhook/receive"
$webhookKey = "your-alertalk-key-here"
$phone     = "5XXXXXXXXX"
$hostname  = $env:COMPUTERNAME

$services = @("W32Time", "Spooler", "wuauserv")

foreach ($svc in $services) {
    $status = (Get-Service -Name $svc -ErrorAction SilentlyContinue).Status

    if ($status -ne "Running") {
        $body = @{
            phone_number  = $phone
            error_message = "Service alert: $svc on $hostname is not running. Status: $status"
        } | ConvertTo-Json

        Invoke-RestMethod -Uri $webhookUrl `
            -Method POST `
            -Headers @{ "X-Webhook-Key" = $webhookKey; "Content-Type" = "application/json" } `
            -Body $body
    }
}

Disk Usage Alert

$webhookUrl = "https://tr.alertalk.net/webhook/receive"
$webhookKey = "your-alertalk-key-here"
$phone     = "5XXXXXXXXX"
$threshold = 85
$hostname  = $env:COMPUTERNAME

Get-PSDrive -PSProvider FileSystem | Where-Object { $_.Used -gt 0 } | ForEach-Object {
    $total = $_.Used + $_.Free
    $usedPercent = [math]::Round(($_.Used / $total) * 100)

    if ($usedPercent -ge $threshold) {
        $body = @{
            phone_number  = $phone
            error_message = "Disk alert: Drive $($_.Name) on $hostname is at $usedPercent percent."
        } | ConvertTo-Json

        Invoke-RestMethod -Uri $webhookUrl `
            -Method POST `
            -Headers @{ "X-Webhook-Key" = $webhookKey; "Content-Type" = "application/json" } `
            -Body $body
    }
}

Windows Event Log Alert

Triggers a voice call when critical Event Log entries are detected:

$webhookUrl = "https://tr.alertalk.net/webhook/receive"
$webhookKey = "your-alertalk-key-here"
$phone     = "5XXXXXXXXX"
$hostname  = $env:COMPUTERNAME

$events = Get-EventLog -LogName System -EntryType Error -Newest 10 `
    -After (Get-Date).AddMinutes(-10) -ErrorAction SilentlyContinue

if ($events) {
    $count = $events.Count
    $body = @{
        phone_number  = $phone
        error_message = "Event Log alert: $count critical errors detected on $hostname in the last 10 minutes."
    } | ConvertTo-Json

    Invoke-RestMethod -Uri $webhookUrl `
        -Method POST `
        -Headers @{ "X-Webhook-Key" = $webhookKey; "Content-Type" = "application/json" } `
        -Body $body
}

Running Automatically with Scheduled Task

To run the script periodically using Windows Task Scheduler:

$action  = New-ScheduledTaskAction -Execute "powershell.exe" `
    -Argument "-NonInteractive -ExecutionPolicy Bypass -File C:\Scripts\alarm.ps1"

$trigger = New-ScheduledTaskTrigger -RepetitionInterval (New-TimeSpan -Minutes 5) `
    -Once -At (Get-Date)

Register-ScheduledTask -TaskName "AlertalkDiskMonitor" `
    -Action $action -Trigger $trigger -RunLevel Highest

PowerShell Alert Scenarios

Who Is This For?

Ideal for system administrators managing Windows infrastructure. Particularly useful in environments without a dedicated monitoring tool or where specific custom alert scenarios are needed alongside an existing stack. PowerShell and Alertalk together provide a fast and effective solution with no additional software required.

Setup Guide

For creating an Alertalk account and getting your webhook key:

Webhook Integration Documentation

PowerShell Integration Documentation

Try Alertalk for Free