head to head
MailHog vs MailCatcher
Two older Go and Ruby catchers, both trailing Mailpit on maintenance and HTML rendering.
What matters for teams choosing a transactional API
Judged purely as an API. What the request contract guarantees on retry, how complete the webhook event coverage is, whether suppressions are readable and writable programmatically, and how much the message log retains when something needs debugging in production.
| Priority | MailHog | MailCatcher |
|---|---|---|
| Idempotency keys | No | No |
| Webhooks | No | No |
| Event stream | No | No |
| Operating since | Not published | Not published |
| Suppressions API | No | No |
| Best published rate per 1,000 | Tiers not published in comparable form | Tiers not published in comparable form |
| Batch sending | No | No |
| SDKs | None | None |
| Deliverability | Not applicable; capture-only. | Not applicable. |
For a transactional workload running high-frequency programmatic sends where a missed delivery is a product failure, the two are level on every priority that can be scored here, so the choice comes down to price and to which product your team would rather operate. That ordering reflects this audience. Weigh the same table differently and the answer changes.
Side by side
| Feature | MailHog | MailCatcher |
|---|---|---|
| Webhooks | No | No |
| SDKs | None | None |
| Deliverability | Not applicable; capture-only. | Not applicable. |
| Tagline | Classic local SMTP catcher (unmaintained since 2020). | Tiny Ruby-based local SMTP catcher. |
| Free tier | Free, MIT-licensed | Free, MIT-licensed |
| Starts at | Free | Free |
| Pricing model | self-hosted | self-hosted |
| API | Yes | Yes |
| SMTP | Yes | Yes |
| Templates | none | none |
| React Email | No | No |
| Inbound | No | No |
| Multi-tenant | No | No |
| Idempotency | No | No |
| Dedicated IP | No | No |
| DX score | 5/10 | 6/10 |
| Best for | Legacy projects already wired to it. | Rails teams already running it in development. |
MailHog
pros
- ›Familiar from years of tutorials and boilerplates
- ›Single Go binary with a Docker image and a chaos-testing mode
cons
- ›No meaningful releases since 2020
- ›HTML and modern CSS rendering trails current email clients
- ›Open issues and pull requests are effectively unattended
MailCatcher
pros
- ›Installs as a Ruby gem, familiar in Rails stacks
- ›SMTP on 1025 with a web UI and JSON API on 1080
- ›Shows HTML, plain text, and raw source per message
cons
- ›Release cadence is slow with little active feature work
- ›Needs a Ruby runtime where Mailpit ships a static binary
- ›HTML rendering trails newer catchers