Netlify Functions and SMTP
Runtime: Netlify’s own Functions runtime (AWS Lambda compatibility mode is deprecated)
Verdict: Unconfirmed. The old Lambda-compatibility mode is being retired, and whether its replacement supports raw outbound TCP isn’t documented either way.
What actually happens on this platform
A common assumption is that Netlify inherits AWS Lambda’s exact networking behaviour, because Netlify Functions used to run in an explicit Lambda-compatibility mode. That mode is now deprecated in Netlify’s own documentation, with migration pointed at a new, non-Lambda Functions API (@netlify/aws-lambda-compat exists only as a backward-compatible shim for the old handler signature, run on the new runtime). Neither the Functions overview nor the API reference pages state whether that new runtime supports raw sockets.
The part worth reading twice
Treat this one as unverified rather than working or blocked. If you’re deploying an SMTP send from Netlify, test the actual connection in a real deployment before relying on it - do not assume Lambda’s behaviour carries over, since the underlying runtime has changed.
If it works here
The connection itself is the same as everywhere else: point at mx.msgwing.com on port 587 (STARTTLS) or 465 (SSL/TLS), authenticate with a username and password. Register at msgwing.com first, then use the Node.js/TypeScript example unmodified - nothing about running inside this platform changes the SMTP conversation itself, only whether the platform lets you open that connection in the first place.
Where this came from
Read off Lambda compatibility, Netlify Functions’s own documentation, checked 2026-08-30 - rather than recalled. If that page and this one now disagree, that page is right and this one is out of date - say so.
Related
Last reviewed 2026-08-30.
Updated 30 Aug 2026