Replace Send-MailMessage in PowerShell — It's Deprecated

#powershell #windows #devops #tutorial

Microsoft deprecated Send-MailMessage in PowerShell. The official docs now say "This cmdlet does not guarantee secure connections to SMTP servers" and recommend against using it. But thousands of production scripts still depend on it for alerts, reports, and automation.

The replacement options aren't great. Send-MgUserMessage requires Microsoft Graph SDK setup and Azure AD app registration. Raw System.Net.Mail.SmtpClient is also deprecated. Building OAuth2 token flows from scratch takes hours.

Nylas CLI gives you a one-line replacement that handles OAuth automatically for Gmail, Outlook, Exchange, Yahoo, iCloud, and IMAP. No SMTP config, no app passwords, no token refresh logic.

Before and after

Send-MailMessage (deprecated)

# Old way — deprecated, insecure, requires SMTP config
Send-MailMessage `
  -From "you@company.com" `
  -To "team@company.com" `
  -Subject "Daily Report" `
  -Body "See attached." `
  -Attachments "report.csv" `
  -SmtpServer "smtp.office365.com" `
  -Port 587 `
  -UseSsl `
  -Credential (Get-Credential)

Nylas CLI (replacement)

# New way — OAuth, no SMTP, no credentials in scripts
nylas email send `
  --to "team@company.com" `
  --subject "Daily Report" `
  --body "See attached." `
  --attach "report.csv" `
  --yes

No SMTP server. No port. No credentials stored in your script. OAuth2 tokens are managed by the CLI and refreshed automatically.

Install on Windows

# One-line install via PowerShell
irm https://cli.nylas.com/install.ps1 | iex

# Verify
nylas --version

For macOS/Linux, use brew install nylas/nylas-cli/nylas. Full install options in the getting started guide.

Authenticate once

nylas auth login
nylas auth whoami
# => Authenticated as you@company.com (Microsoft 365)

The CLI opens a browser for OAuth consent. After that, your scripts run unattended — no Get-Credential prompts, no stored passwords.

Migration examples

Simple notification email

# Before (Send-MailMessage)
Send-MailMessage -To "ops@company.com" -Subject "Build failed" `
  -Body "CI pipeline failed at $(Get-Date)" -SmtpServer "smtp.gmail.com"

# After (Nylas CLI)
nylas email send --to "ops@company.com" `
  --subject "Build failed" `
  --body "CI pipeline failed at $(Get-Date)" --yes

Email with attachment

# Before
Send-MailMessage -To "finance@company.com" -Subject "Monthly Report" `
  -Body "Report attached." -Attachments "C:\Reports\monthly.xlsx" `
  -SmtpServer "smtp.office365.com" -Port 587 -UseSsl -Credential $cred

# After
nylas email send --to "finance@company.com" `
  --subject "Monthly Report" `
  --body "Report attached." `
  --attach "C:\Reports\monthly.xlsx" --yes

Multiple recipients with CC/BCC

# Before
Send-MailMessage -To "alice@team.com" -Cc "bob@team.com" `
  -Bcc "manager@team.com" -Subject "Sprint update" `
  -Body "All tasks on track." -SmtpServer "smtp.gmail.com"

# After
nylas email send --to "alice@team.com" `
  --cc "bob@team.com" --bcc "manager@team.com" `
  --subject "Sprint update" --body "All tasks on track." --yes

HTML email body

# Before
Send-MailMessage -To "team@company.com" -Subject "Status" `
  -Body "<h1>All Green</h1><p>No incidents today.</p>" `
  -BodyAsHtml -SmtpServer "smtp.office365.com"

# After
nylas email send --to "team@company.com" `
  --subject "Status" `
  --body "<h1>All Green</h1><p>No incidents today.</p>" --yes

Read and search email too

Unlike Send-MailMessage, which is send-only, Nylas CLI also reads your inbox:

# List recent emails
nylas email list --limit 10

# Search
nylas email search "invoice" --json | ConvertFrom-Json

# Unread count
(nylas email list --unread --json | ConvertFrom-Json).Count

Full guide: Read and Search Email in PowerShell

Scheduled sends

# Send tomorrow morning
nylas email send --to "team@company.com" `
  --subject "Monday standup" --body "Agenda attached." `
  --schedule "tomorrow 9am" --yes

Bulk send from CSV

Import-Csv contacts.csv | ForEach-Object {
    nylas email send `
      --to $_.Email `
      --subject "Hello $($_.Name)" `
      --body "Your account is ready." --yes
    Start-Sleep -Seconds 2
}

For advanced mail merge with variable substitution, see CLI Mail Merge.

Task Scheduler automation

Replace your scheduled Send-MailMessage scripts by swapping the command:

# Create a scheduled task that sends a daily report
$Action = New-ScheduledTaskAction -Execute "nylas" `
  -Argument 'email send --to "team@company.com" --subject "Daily Report" --body "Automated report" --yes'
$Trigger = New-ScheduledTaskTrigger -Daily -At "8:00AM"
Register-ScheduledTask -TaskName "DailyEmailReport" -Action $Action -Trigger $Trigger

Full automation guide: Automated Email Reports with PowerShell

Works with Office 365, Gmail, and more

The same commands work regardless of your email provider. No SMTP server changes when you switch providers:

Monitor your inbox

Build alerting scripts that watch for specific emails:

# Poll for emails from a specific sender
nylas email list --from "alerts@monitoring.com" --unread --json

Full guide: Monitor Your Inbox with PowerShell

CI/CD integration

Works in GitHub Actions and Azure DevOps pipelines:

# GitHub Actions
- name: Send deployment notification
  run: |
    nylas email send --to "team@company.com" \
      --subject "Deployed v${{ github.ref_name }}" \
      --body "Deployment complete." --yes