Can I send SMTP from a serverless platform?
August 30, 2026 ยท View on GitHub
A question that has nothing to do with the December 2026 Basic auth shutdown, and gets asked anyway: some serverless and edge runtimes cannot open a raw TCP socket at all, which means SMTP was never possible there regardless of what the mail server on the other end requires.
| Platform | Runtime | Verdict |
|---|---|---|
| Cloudflare Workers | V8 isolate (edge) | Works |
| Vercel | Node.js Functions (default) or Edge Runtime (opt-in) | Depends on the runtime |
| Netlify Functions | Netlify's own Functions runtime (AWS Lambda compatibility mode is deprecated) | Unconfirmed |
| AWS Lambda | Lambda execution environment (container-based, full Node.js) | Works |
Each page names the exact API involved, quotes where that came from, and states plainly when something could not be confirmed rather than guessing which way it goes.
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Last reviewed 2026-08-30.