InboxTap is a free, open-source SMTP capture server and test SDK for signup verification, password resets, OTPs, invitations, and other email flows. Run it locally, point your app to localhost, and let your tests read the real link or code. Each test gets an isolated inbox, so parallel runs do not mix messages. Nothing is delivered externally. Works with Playwright, Vitest, Jest, Bun, and Node 20+.

Hi Product Hunt 👋 I built InboxTap after getting tired of switching between Gmail accounts just to test verification links and OTPs. Mocks could tell me that the send function ran, but not whether a user could complete the flow. Real inboxes added setup, credentials, and waiting. Shared inboxes also caused problems when tests ran in parallel. InboxTap runs on localhost and catches every email your app sends. Each test can create its own inbox, trigger the real email, read the link or code, and keep going. Nothing leaves your machine. I made InboxTap free and open source because email flows are a basic part of app development. I understand why hosted tools charge, but I do not think every local developer tool needs another subscription. This is one way I can support the developer community. The tool is intentionally small. There is no visual inbox, persistence, or external delivery. It focuses on automated tests with Playwright, Vitest, Jest, Bun, and Node. I would love to hear how you test email flows today. What would InboxTap need before you would use it in CI?

One thing I'd love is built-in support for asserting on email content in popular test runners, like a Vitest matcher for checking that an inbox contains an email with a specific subject or link. Would make assertions feel a lot more native instead of writing custom helpers every time.

finally something that makes email flow testing not painful, the isolated inboxes per test run are basically exactly what i needed for parallel CI. works great with my vitest setup so far

InboxTap

Test email flows locally, without risking real inboxes

Test email flows locally, without risking real inboxes