Mailhog alternative

The hosted Mailhog alternative for teams, CI, and real email testing

Maildog is the hosted Mailhog alternative built for teams, CI pipelines, and staging environments. Catch every test email in a real cloud inbox, validate SPF, DKIM, and DMARC, test inbound mail, and check deliverability — without self-hosting or patching an unmaintained tool. Point your SMTP config at mail.maildog.io:2525 and you are done.

Start testing email free View pricing

Mailhog is great on your laptop, not your team

Mailhog is a tiny Go binary that captures whatever your app sends and shows it in a web UI. For a single developer on localhost it is hard to beat — but the moment email testing has to leave one laptop, its limits show up fast.

Localhost-only by design

Mailhog listens on 127.0.0.1:1025. It is not reachable from a cloud CI runner, a remote teammate, a preview deployment, or a staging box without you building and securing your own networking around it.

No team or CI access out of the box

Every developer runs their own isolated instance. There is no shared inbox the whole team — or a GitHub Actions / GitLab CI job — can write to and read from, so you end up wiring up tunnels, port forwards, or a fragile self-hosted deployment.

No SPF, DKIM, or DMARC validation

Mailhog captures the message but does not tell you whether your authentication records would actually pass. You can read the raw headers, but there is no verdict on whether real inbox providers would trust the mail.

Unmaintained, with no inbound or sending path

Mailhog's upstream development has stalled for years, the community points new users to Mailpit, and it can neither receive inbound mail nor deliver a real transactional email — it is a capture-only black hole you host and patch yourself.

Keep the safety, drop the operational tax

Maildog keeps the part of Mailhog you love — emails land in a sandbox and never reach real users — and removes the operational tax. Instead of a binary you host yourself, you get a hosted email sandbox with a real SMTP endpoint at mail.maildog.io and per-inbox credentials your whole team and every CI job can reach.

Validate authentication automatically. Maildog validates SPF, DKIM, and DMARC on every captured message and tells you whether your authentication would actually pass — not just raw headers to decode by hand.

Score deliverability before production. Spam-risk and deliverability scoring catches inbox-placement problems in staging instead of in a customer's spam folder.

Test inbound and send for real. Inbound email testing gives you real addresses to receive and inspect incoming mail, and a developer-friendly transactional email API provides a genuine, authenticated sending path when you are ready.

Change one host, not your code. You do not deploy or patch anything. Swap one host in your SMTP config and your existing test suite starts filling a real, shared inbox.

Key features

Hosted email sandbox

A real, always-on email sandbox at mail.maildog.io. Every message your app sends is captured and safely contained — it never reaches actual recipients — and the same inbox is reachable from your laptop, a teammate's machine, staging, and CI with one set of credentials.

Team and CI-ready SMTP

Each sandbox inbox has a unique SMTP username and password from the inbox Integration tab. Drop them into a GitHub Actions secret, a GitLab CI variable, or staging, and your email tests work the same everywhere — no tunnels, no port forwarding, no self-hosted instance.

SPF, DKIM & DMARC validation

Maildog inspects the authentication results of every captured message and gives a clear pass/fail verdict for SPF, DKIM, and DMARC — the single biggest gap a Mailhog or Mailpit setup leaves open.

Deep inspection and debugging

View rendered HTML, plain-text fallback, raw source, headers, and every attachment for any captured message. Spam-score and deliverability checks flag broken authentication, risky content, and missing headers so email debugging stops being guesswork.

Inbound email testing

Maildog goes beyond capture. You get real addresses to receive mail at, so you can verify replies, parsing, and webhook handling end to end — something a localhost-only fake SMTP server can never do.

Real transactional sending API

When you are ready to actually deliver mail, the developer-friendly transactional email API gives you a real, authenticated sending path — bridging the gap between capture-only testing and production.

Migrate from Mailhog in one config change

Mailhog and Maildog both speak plain SMTP, so migrating is usually swapping a host, a port, and adding credentials. Your application code does not change.

Before — generic SMTP env pointing at local Mailhogenv

SMTP_HOST=localhost
SMTP_PORT=1025
SMTP_SECURE=false
SMTP_USER=
SMTP_PASS=

After — the same env pointing at your Maildog sandboxenv

SMTP_HOST=mail.maildog.io
SMTP_PORT=2525
SMTP_SECURE=false        # STARTTLS is negotiated on 2525/587
SMTP_USER=your-sandbox-username   # from the inbox Integration tab
SMTP_PASS=your-sandbox-password   # from the inbox Integration tab

Nodemailer — Mailhog configjs

const nodemailer = require("nodemailer");

const transport = nodemailer.createTransport({
  host: "localhost",
  port: 1025,
  secure: false,
  // Mailhog accepts mail with no auth
});

Nodemailer — Maildog sandbox configjs

const nodemailer = require("nodemailer");

const transport = nodemailer.createTransport({
  host: "mail.maildog.io",
  port: 2525,        // STARTTLS, primary. Use 587 as an alternative,
  secure: false,     // or 465 with secure: true for implicit TLS.
  auth: {
    user: process.env.SMTP_USER, // unique per sandbox inbox
    pass: process.env.SMTP_PASS, // see the Integration tab in the panel
  },
});

await transport.sendMail({
  from: "app@maildog.io",
  to: "test@example.com",
  subject: "Migrated from Mailhog in one config change",
  html: "<h1>It works</h1><p>This landed in the Maildog sandbox.</p>",
});

Why developers choose Maildog

Faster debugging

Rendered HTML, raw source, headers, attachments, and authentication verdicts sit on one screen. No more decoding raw headers by hand or guessing why a template looks wrong in one client.

Safe email testing

Like Mailhog, nothing in the sandbox is ever delivered to a real recipient. Unlike Mailhog, that safety net is shared by your whole team and every CI run without exposing a debug SMTP server to the internet.

Better deliverability

SPF, DKIM, DMARC, and spam scoring catch inbox-placement problems in staging instead of in a customer's spam folder. You ship email that real providers trust.

Improved workflow

One hosted endpoint replaces per-developer self-hosting. Onboarding a new engineer or wiring up a CI job is a matter of copying credentials, not deploying infrastructure.

Mailhog vs Mailpit vs Maildog

Mailpit is the maintained successor to Mailhog and an excellent choice for fast, offline, solo local development. Maildog solves the next problem: shared, authenticated, CI-grade email testing with inbound support and a true sending path.

Capability	Mailhog	Mailpit	Maildog
Hosting	Self-hosted binary	Self-hosted binary	Hosted, no install
Team / CI access	Local only	Local only	Shared inbox, one credential set
SPF / DKIM / DMARC validation
Inbound email testing
Real sending path	Capture only	Capture only	Transactional API
Maintenance	Largely unmaintained	Actively maintained	Managed for you

Frequently asked questions

Is Mailhog still maintained?

Mailhog's upstream development has effectively stalled for years and the project is widely considered unmaintained. The community now points new users toward Mailpit, an actively maintained successor that offers similar local SMTP capture with a modern UI.

What is the best Mailhog alternative?

It depends on the job. For solo, offline local development, Mailpit is the best like-for-like replacement — it is maintained and fast. For shared email testing across a team, CI pipelines, and staging — with SPF/DKIM/DMARC validation, inbound testing, and a real sending path — Maildog is the stronger fit because it is hosted and team-ready out of the box.

What is the difference between Mailhog and Mailpit?

Both are self-hosted fake SMTP servers that capture email locally for inspection. Mailpit is essentially the maintained, modernized successor to Mailhog, with an updated web UI and active development. Neither is reachable across a team or CI without you adding your own networking, and neither validates email authentication or provides a real sending path.

Can I use Mailhog in CI/CD pipelines?

You can run Mailhog as a service container inside a CI job, but its inbox stays local to that job — it is not a shared, persistent inbox your team can also inspect, and it offers no authentication validation. Maildog gives every CI run and every teammate the same hosted sandbox inbox using one set of SMTP credentials, so test email is consistent across local, CI, and staging.

Does Maildog work as a drop-in replacement for Mailhog?

For the capture use case, yes — both speak plain SMTP. Migrating usually means changing your SMTP host from localhost:1025 to mail.maildog.io:2525 and adding the username and password from your inbox's Integration tab. Your application code does not change.

Can Mailhog validate SPF, DKIM, and DMARC?

No. Mailhog (and Mailpit) capture the message and let you read its raw headers, but they do not produce a pass/fail verdict for SPF, DKIM, or DMARC. Maildog validates all three on every captured message so you know whether real inbox providers would trust your mail.

Does Maildog actually send email, or just capture it?

Both, depending on what you need. The sandbox captures test email so it never reaches real recipients — exactly like Mailhog. When you are ready to deliver real mail, Maildog also offers a developer-friendly transactional email API with a genuine, authenticated sending path.

What ports does the Maildog sandbox SMTP support?

Use port 2525 with STARTTLS (secure: false) as the primary option, 587 as an alternative (also secure: false), or 465 for implicit TLS (secure: true). The host is mail.maildog.io, and each sandbox inbox has unique credentials shown on its Integration tab in the panel.

Keep exploring

Hosted email sandboxThe shared sandbox that replaces a local Mailhog.Fake SMTP server alternativeThe capture engine behind the sandbox.SMTP testing in CIWire the sandbox into GitHub Actions or GitLab CI.Validate SPF, DKIM, and DMARCPass/fail verdicts on every captured message.Inbound email testingReal addresses to receive and inspect mail.Compare Maildog to MailtrapHow hosted sandbox options stack up.

Outgrow Mailhog without losing the safety net

Point your SMTP config at mail.maildog.io:2525 and start filling a real, shared sandbox in minutes.

Start testing email free