SMTP OAuth2 Infrastructure Migration
Migrating every outgoing email server-wide — while the mail kept flowing.
#01 The challenge
Google and Microsoft announced the end of basic authentication for SMTP. Jotform’s notification emails — the core of a forms product — ran through legacy password-based SMTP configured by thousands of customers, including enterprise servers we did not control.
Failure mode was brutal and silent: emails simply stop arriving. For a business built on form submissions, that is the product breaking.
#02 Architecture & approach
I led the modernization to OAuth2 flows for Gmail and Microsoft plus hardened custom SMTP support. The system continuously ran connection-health detection against configured senders, flagged failing configurations before customers noticed, and routed messages through fallback delivery when a sender degraded.
For enterprise, admins gained centralized enforcement: organization-wide SMTP configuration, token lifecycle handling, and per-product overrides. Token refresh, revocation, and provider quirks (each provider has many) were absorbed by a single messaging layer shared across products.
#03 Rollout & outcome
Migration shipped as a staged rollout across paid, Teams, and Enterprise environments — feature-flagged, canaried, and reversible at every step. Zero downtime, zero mass delivery incidents.
The step-wizard UI built with the 2FA team guided customers through re-authentication, keeping support volume flat during a migration touching every account with custom SMTP.
$ ls ./screenshots
Want the full story behind this build?
POST /contact