Getting started
InboxTap vs MailHog, Mailpit, and Mailtrap
Compare InboxTap with MailHog, Mailpit, smtp4dev, Mailtrap, and Ethereal for local email testing.InboxTap is a no-Docker MailHog alternative when an automated test needs to retrieve links, OTPs, or custom values through a TypeScript SDK. It is not a drop-in replacement for MailHog's browser inbox: teams that need visual inspection, persistence, attachments, or manual QA should choose a viewer or hosted sandbox instead.
At a glance
| Tool | Interface | Runs as | Best for |
|---|---|---|---|
| InboxTap | Typed SDK and HTTP API | npm CLI or in-process | Deterministic automated tests |
| Mailpit | Web UI and REST API | Go binary or Docker | Inspecting rendered mail during development |
| MailHog | Web UI and API | Go binary or Docker | Existing MailHog setups and manual inspection |
| smtp4dev | Web UI and IMAP | .NET binary or Docker | Cross-platform manual inspection |
| Ethereal and Mailtrap | Hosted web inbox | SaaS | Hosted previews, analysis, and team workflows |
Is InboxTap a no-Docker MailHog alternative?
Yes, when the goal is programmatic email testing from a JavaScript or TypeScript test suite.
npx inboxtap starts a local SMTP capture server without Docker, and the SDK waits for messages,
links, codes, or regular-expression matches. No, when the goal is a browser inbox for manually
reading and inspecting rendered email; InboxTap intentionally has no dashboard.
Mailpit and MailHog
Mailpit and MailHog are local SMTP servers built around a browser inbox: send mail, open the UI, and read it. Mailpit is actively maintained, ships as a single binary or Docker image, and provides a REST API that tests can poll.
Neither ships a test SDK. Assertions mean hand-rolling HTTP polling, link and code extraction, and
per-test recipient isolation — the pieces InboxTap's TestInbox provides. They also run as a
separate binary or container, where InboxTap installs from npm and can start inside the test
process. If the goal is to look at emails rather than assert on them, they are the better tool.
smtp4dev
smtp4dev is a cross-platform .NET tool with a web UI and IMAP access, so a desktop mail client can browse captured messages. Like the Go viewers, it is built for inspection: good for watching what an application sends, while tests still need custom polling and parsing code.
Hosted services
Ethereal and Mailtrap Email Sandbox accept mail over the network into a hosted inbox. They are useful for manual QA, HTML analysis, and shared team workflows. The same network hop adds credentials, latency, and service limits to a test suite—and messages leave the machine, which local capture never does.
When not to use InboxTap
InboxTap has no browser inbox, no persistence across restarts, and no attachments workflow. Choose a viewer when a team wants a shared, browsable inbox, or a hosted service when the job is checking deliverability and rendering in real clients. InboxTap's lane is narrower on purpose: deterministic, parallel-safe email assertions running next to the test that triggered them.