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Testing the email step
Short, practical answers for engineers who test sign-up, reset and login emails: with code, sources and the limits stated plainly.
How long should a test wait for an email?
Wait for the first email with one long-poll request, set the test timeout above it, and count API requests per run before you pick a plan.
Read →October 16, 2026Why your E2E test opened the wrong email
Reused addresses, a second email to the same inbox and parallel workers. Four causes of a test reading the wrong email, and how to rule each out.
Read →October 16, 2026Testing emails in GitHub Actions
Store the API key as a secret, build addresses from GITHUB_RUN_ID and GITHUB_RUN_ATTEMPT, and know why pull requests from forks get no secrets.
Read →October 16, 2026Sandbox modes of SendGrid, Postmark, Resend and SES: what gets delivered
In sandbox or test mode most providers accept the email and deliver nothing. What each one does, and how to test real delivery from staging.
Read →October 16, 2026Getting the verification link out of an email (and why click tracking breaks it)
Pick the link by text or path, not position. Click tracking rewrites URLs to the provider's domain: turn it off for staging or follow the redirect.
Read →October 16, 2026Reading a one-time code from an email without false matches
A bare \d{6} matches order numbers and dates. Anchor the pattern to the words around the code, normalize the text and require exactly one match.
Read →October 16, 2026Plus addressing, catch-all and subdomains: how test email addresses work
Plus addresses share one mailbox, catch-all needs your own domain, subdomain inboxes need DNS. How each format routes mail, and what that means for tests.
Read →October 16, 2026Mailpit locally, a real inbox on staging: where each one fits
Mailpit catches SMTP on your machine; it can't see mail sent through a provider's API. Use it locally and a real inbox where delivery matters.
Read →October 16, 2026Why emails from staging land in spam: SPF, DKIM and DMARC
Staging often sends from a domain with no SPF, an unsigned DKIM or a From that doesn't align. How to read the headers of a received email and fix it.
Read →October 16, 2026Cleaning up after email tests: delete over the API or let retention do it
Temporary test mail expires on its own. Delete over the API when inboxes are reused or hold personal data, and count the requests it costs.
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