MailTub

MailTub is a free, open-source service for hosting disposable email inboxes yourself. New messages arrive through WebSocket push instead of repeated polling. A session can keep up to five inboxes, each set to expire after 1 hour, 6 hours, 24 hours, or 7 days. MailTub supports MIME attachments with configurable size caps, and inboxes can be exported as an .eml ZIP or structured JSON. It runs as a single Go binary with SQLite and an embedded React interface, or can be deployed through Docker. Its web interface has dark, light, and system themes and can be installed as a progressive web app on mobile and desktop. Additional tools include a REST API, SMTP receiving, WebSocket updates, a scriptable CLI, and a Prometheus-compatible metrics endpoint. Mailbox creation is limited to 20 per IP per hour. To receive real email, the server needs a domain with an MX record pointing to it, port 25 access or redirection, and a matching MAILTUB_DOMAIN setting. The project identifies its license as Apache 2.0.

MailTub offers several deployment and integration options for self-hosted disposable email. Receiving real mail requires specific domain and port setup, and mailbox creation has a per-IP limit.

MailTub suits people who want to deploy and manage temporary inboxes themselves. It also fits users who need API, CLI, or SMTP receiving options and can provide the required email-server setup.

MailTub is a self-hosted disposable-email service for running temporary inboxes on infrastructure you control. It is aimed at developers, testers, and operators who can configure mail delivery and want an open system rather than a hosted throwaway address. Its live updates and automation interfaces are strong, but the server and domain requirements make it a poor fit for instant, no-maintenance use.

Overview

MailTub is free, open-source software under the Apache 2.0 license. You can run it as one Go binary backed by SQLite with an embedded React interface, or deploy it with Docker. That deployment flexibility suits anything from a small test server to a container-based setup, while still leaving administration and mail routing in your hands.

Receiving actual email requires a domain with an MX record pointing at the server, access to port 25 or a redirection, and a matching MAILTUB_DOMAIN setting. Without that mail infrastructure, you have an inbox application but not a complete receiving service. Mailbox creation is limited to 20 per IP per hour, a practical safeguard that can interrupt high-volume automated provisioning.

Key features

Live inboxes with controlled lifetimes

New messages arrive through WebSocket push instead of polling, so clients can react as mail arrives. A session supports up to five simultaneous inboxes, with expiry choices of 1 hour, 6 hours, 24 hours, or 7 days. Short expiries fit verification tests; the seven-day option covers longer temporary projects. The five-inbox ceiling, however, limits parallel test runs and multi-user sessions.

Attachments and exports

MailTub parses MIME attachments and lets users export an inbox as an .eml ZIP or structured JSON. Those formats are useful for preserving test messages, feeding another tool, or analyzing a complete mailbox rather than copying text manually. Default limits allow a 25 MiB SMTP message, a 25 MiB individual attachment, and 50 MiB of attachments in one email; operators can configure attachment caps to match their storage and abuse policies.

API, CLI, and operations

A REST API and scriptable CLI cover creating, listing, reading, watching, and sending mail, making MailTub practical for CI pipelines and repeatable test harnesses. SMTP receiving handles inbound mail, WebSocket updates power the live view, and a Prometheus-compatible endpoint exposes metrics for monitoring. Optional mailbox caching can use Redis or an Upstash URL when SQLite-only operation is not the preferred arrangement.

Interface and security controls

The web interface offers dark, light, and system themes and can be installed as a progressive web app on mobile or desktop. The admin password is stored as a bcrypt hash, while session cookies use HMAC-SHA256 signatures and last 24 hours. API access is open by default unless you configure an API key; the health endpoint remains public, so deployments should account for that exposure when designing access controls.

Pricing

MailTub is free to use and open source, with no paid tiers or subscription renewal. That is attractive for self-hosters who can supply the server, domain, and mail networking themselves. The trade-off is operational rather than monetary: you absorb hosting, configuration, monitoring, and abuse-management responsibilities, and the 20-mailboxes-per-IP hourly limit still applies.

Platforms

MailTub supports Android, iOS, Linux, macOS, Windows, and web access, with API and self-hosted deployment options. The progressive web app makes the browser interface installable on mobile and desktop, while the CLI and REST API target scripted workflows. The service is most naturally operated on a server, regardless of which client device you use.

Who it's for

Choose MailTub if you are a developer or operator who needs disposable inboxes inside your own environment, real-time delivery events, exports, and programmatic control. It is well suited to integration tests, staging systems, and teams that want to set their own mailbox lifetimes and retention behavior. Look elsewhere if you need a ready-made address immediately, cannot arrange MX and SMTP access, or expect more than five concurrent inboxes per session.

Pros and cons

• Pros: Free Apache 2.0 software avoids per-mailbox fees and vendor lock-in.
• Pros: WebSocket delivery, REST, CLI, SMTP, and Prometheus metrics support both interactive and automated workflows.
• Pros: Seven-day expiry, attachment parsing, and ZIP/JSON exports cover more than one-off message viewing.
• Pros: Single-binary, Docker, SQLite, and optional Redis/Upstash deployment give operators several hosting patterns.
• Cons: MX, port 25, and domain configuration are mandatory for real inbound mail, adding infrastructure work that hosted services avoid.
• Cons: Five simultaneous inboxes per session and 20 creations per IP per hour constrain larger parallel jobs.
• Cons: API access is open by default, so secure configuration is part of deployment rather than an automatic default.

Alternatives

EmailOnDeck is a freemium hosted option with Android, iOS, web, API, and extension access; its free tier supports one email at a time and is ad supported, making it more convenient when you do not want to run a server.

Temp-Mail.org offers free receive-only inboxes with messages stored for up to 1–2 hours, plus a $10.00-per-month premium plan, so it fits short-lived hosted use better than self-hosting.

TempMailPortal provides free web and Android inboxes with messages expiring within up to 24 hours.

Temp Mail API is a freemium choice for API users; its premium plan includes 1,000 requests per month, 10 custom domains, saved messages, forwarding, and 10 simultaneous emails.

1secemail is a free web-only temporary email service with no subscription requirement.

Emailnator provides public, no-signup inboxes, message deletion after 24 hours, and up to 100 addresses at once, with API and web access.

MailDrop offers a free tier with 300 requests per day and one mailbox per 24 hours, plus a $5.00-per-month Starter plan for higher quotas.

Mailinator is a freemium API and web service with a free Verified Pro option that includes private inboxes, one private domain, permanent storage, and defined message-rate and monthly limits.

For a broader comparison, see Disposable Email Services.

Verdict

MailTub is the right choice for technically capable users who want free, self-hosted disposable mail with live events and strong scripting support. Choose it for control and integration; choose a hosted alternative when configuring DNS, SMTP access, and ongoing security is more work than the temporary inbox is worth.