Email verification testing checklist: signup, resend, and expired codes

Updated October 11, 2026 · TossMyMail

A temporary inbox is useful for a manual test of your own application’s signup emails without cluttering a personal mailbox. It complements your test environment; it does not replace automated delivery tests.

Run a complete signup

1. Open TossMyMail and copy an active address.
2. Use it to register in your application’s test environment.
3. Return to the inbox and wait for the next check.
4. Open the message and check its sender, subject and plain-text content.
5. Copy the likely verification code or open the link, checking the destination first.
6. Confirm that your application completes verification.

Test resend and expiry

Request a resend once and check how your application handles old and new codes. Test your application’s code expiration separately from TossMyMail’s inbox expiration. Extend the inbox before its timer ends if needed.

Check the plain-text version

TossMyMail displays plain text and turns HTTP/HTTPS URLs into links. HTML-only messages show a placeholder, and attachments are not displayed. Include a plain-text alternative in your transactional emails. Use a dedicated email-preview tool to test HTML layouts.

Respect testing limits

This public tool allows five inbox creations per IP per minute, 100 messages per inbox and 1 MB incoming messages. Daily backend limits also apply. It is intended for small manual tests, not load testing. Keep real customer data and production secrets out of test messages.

Five cases to test in your own app

1. Fresh signup: the code or link confirms the intended test account.
2. Resend: request a new message once. Check whether the old code still works. Compare that result with your app’s intended rule.
3. Expired code: wait for your app’s code deadline, then try it. Your app should show a clear message and a way to request a new code.
4. Repeat use: try the same link twice. Check that it behaves as your app intends and does not create a second account.
5. Wrong account: use a code with a different test account. It should not confirm the wrong person.

Keep the two timers separate

Your app might give a code five minutes. TossMyMail gives its inbox ten minutes. Adding inbox time does not add time to your app’s code. Keep the inbox active long enough to test the code’s own deadline.

Record the result

Use a note with four fields: test case, what you expected, what happened, and pass or fail. For example: “Old code after resend; expected reject; got reject; pass.” Do not put live passwords or real user codes in your notes.

A copy button can find likely codes beyond the message preview. Check it against the full email; code detection is a helper and may miss a value.