Download SMTPly
14 days of full functionality, no restrictions. After that, relay operation pauses until you activate a license — your configuration and logs are preserved.
SMTPly — Windows installer (x64, latest version)
Launch once, walk through the setup wizard, enter your Azure app registration, done. The installer optionally registers the Windows service "Smtply" with automatic start.
SHA-256: 84425d59d5aec17f1bb20f3af747dafa81cbf376c44a7b4e5f4a71f4aa64d438
Windows note: As of version 1.7.18 the installer is digitally signed, issued to IT-Beratung - Andreas Hähnel. User Account Control shows that name on launch instead of reporting "Unknown publisher".
For a freshly published release, SmartScreen may still say "not commonly downloaded". That rating depends on how often a specific file has been downloaded, not on the signature — it rebuilds after every release.
If the warning appears:
- In the browser download: click "Keep" → "Keep anyway".
- On "Windows protected your PC": click "More info" → "Run anyway".
- Check the signature: right-click the EXE → Properties → Digital Signatures. It must read
IT-Beratung - Andreas Hähnel. - Compare the SHA-256 (PowerShell:
Get-FileHash SMTPly-Setup-latest.exe) — the checksum above still applies.
About the signature: It is produced through Azure Artifact Signing and chains to the Microsoft Identity Verification Root CA. The private key never sits on our build machine — it never leaves Microsoft's hardware security module. Every signature is timestamped and therefore stays valid long after the certificate itself has expired.
System requirements
- Windows 10 / 11 or Windows Server 2016 / 2019 / 2022 / 2025 (x64)
- Administrator rights for initial install and service registration
- A Microsoft 365 tenant with global admin rights for app registration
- Port 25 or 587 available on the bind address
Ready in 5 steps
Run the installer
Run as administrator. Setup places SMTPly under Program Files\SMTPly\ and optionally registers the service.
Register the Azure app
Create an app registration with the Mail.Send application permission in the Entra admin center. The setup wizard shows the exact steps. Guide →
Enter credentials
Enter tenant ID, client ID, client secret and sender address in the GUI. Everything is stored DPAPI-encrypted locally.
Reconfigure the device
On the printer, ERP system or third-party application, set the SMTP server to your Windows server's IP and the configured port. No auth required — SMTPly handles OAuth2 in the background.
Send a test mail
The first mail appears in the mail tracker within seconds. If not, the system log provides a plain-text error message.
What's in the download?
- Smtply.Service.exe — Windows service (worker) with SMTP listener and Graph relay
- Smtply.exe — WPF configuration GUI with dashboard, log viewer and setup wizard
- Self-contained .NET 8 runtime — no separate install needed
- All required libraries — MSAL, Graph SDK, SmtpServer, Serilog, SQLite
Activate your license
After purchase you'll receive a license key by email (format: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX). In the GUI, open the "License" navigation item, paste the key and click "Activate". The license is then bound to the server hardware.
For server migration, first click "Deactivate (release license)" in the GUI — then the same key can be activated on the new server.
No license yet? No problem. After download SMTPly runs 14 days fully functional as a trial. You can purchase and activate a license at any time — even during the trial, to replace the trial counter immediately.
Ready for production?
Starter from €149, Business €249 (from 1 October 2026: €299) — one-time purchase, 1 license per server, unlimited mail volume. Compare editions →