What is Mailpit?
A minimal email testing tool that intercepts SMTP traffic and provides a web UI plus REST API for validating and testing email functionality during development.
What Mailpit does
The capabilities that matter for email testing dev, normalised so it lines up with every alternative. “-” means we haven't confirmed it, not that it's missing.
- API assertions
- -
- Rendering preview
- ✓
- Spam score check
- ✓
- Blocklist deliverability check
- -
- SMS testing
- -
- Production sending addon
- -
- Ci cd integration
- -
- Multi user inboxes
- -
- Open source
- -
Platform & deployment
Independently observed- CLI
- Web
- Self-hosted
Integrations (2)
Independently observed- SpamAssassin
- GitHub→•
Security & compliance
Known vulnerabilities: 0 (0 in the last 12 months) sourcea count reflects scale & disclosure, not quality
Mailpit FAQ
Common questions about Mailpit, answered from independent, dated evidence.
What is Mailpit?
A minimal email testing tool that intercepts SMTP traffic and provides a web UI plus REST API for validating and testing email functionality during development. It is indexed under Email Testing Dev.
Source: https://mailpit.axllent.org
What platforms does Mailpit support?
We have confirmed browser-based access to Mailpit. That is the extent of what we could verify from public sources, so it may well offer desktop or mobile clients we have not indexed.
Source: https://mailpit.axllent.org
Can Mailpit be self-hosted?
Yes. Mailpit can be deployed self-hosted, so it does not have to run on the vendor's infrastructure.
Source: https://mailpit.axllent.org
Is Mailpit open source?
Yes. Mailpit is published under the MIT licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.
Mailpit alternatives
Other email testing dev we track, ranked by the same independent score.
- Testmail.appAPI-based email testing platform for automated QA and CI/CD workflowslow · 45%
- MailosaurPlatform for automated email and SMS testing with integrated message previews and test automation supportmedium · 56%
- Email on AcidEmail testing and validation platform for pre-send campaign quality assurancemedium · 64%
- GreenMailAn open source sandbox for testing email server protocols without sending actual emailslow · 31%
- MailSlurpEmail and SMS testing and automation platform with API and dashboard accessmedium · 54%
- MaildevDevelopment email testing utility with SMTP server and web dashboardlow · 35%
Compare Mailpit
Side by side against other email testing dev, attribute by attribute, with a source on every value.
The vioscaleAI score: one lens on the evidence
Not user reviews and not a paid placement: a confidence-weighted blend of the independent signals below (adoption, activity, security posture, and more), which you can sort and re-weight yourself. Vendors can correct their listing but can never move their rank, and stars are weighted low as a vanity metric. It is one way to read the evidence for Mailpit, not the verdict.
| Signal | Score | Weight | Contribution | Evidence |
|---|---|---|---|---|
| Release cadence | 94 | 0.07 | 6.3 | ✓ |
| Development activity | 52 | 0.12 | 6.2 | ✓ |
| Capabilities | 46 | 0.08 | 3.8 | ✓ |
| Stars | 76 | 0.03 | 2.5 | ✓ |
| Integrations | 14 | 0.05 | 0.7 | ✓ |
| Dependent projects | 5 | 0.08 | 0.4 | ✓ |
| Security posture | 0 | 0.09 | 0.0 | - |
| Package downloads | 0 | 0.17 | 0.0 | - |
| Security score | 0 | 0.05 | 0.0 | - |
| Developer Q&A activity | 0 | 0.08 | 0.0 | - |
Computed . Re-weight it by intent, or see the full method.
All data & sourcesshow ↓
Every value we hold, with its source, retrieval date, and confidence. This is the evidence behind the score: don't trust it, verify it.
Activity
| Attribute | Value | Evidence |
|---|---|---|
| Commits last 30d | 43 | mediumsource · 2026-10-13 · 65% |
Adoption
Content
| Attribute | Value | Evidence |
|---|---|---|
| Faq | 4 items | mediumsource · 2026-09-10 · 69% |
Features
| Attribute | Value | Evidence |
|---|---|---|
| Capabilities | Spam score check, Rendering preview | mediumsource · 2026-09-11 · 60% |
Integrations
| Attribute | Value | Evidence |
|---|---|---|
| Count | 2 | mediumsource · 2026-09-11 · 60% |
Language
| Attribute | Value | Evidence |
|---|---|---|
| Primary | Go | highsource · 2026-10-13 · 90% |
License
| Attribute | Value | Evidence |
|---|---|---|
| Spdx | MIT | highsource · 2026-10-13 · 95% |
Release
Security
| Attribute | Value | Evidence |
|---|---|---|
| Vulnerabilities | Count: 0 · Source: https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=homebrew&package_name=mailpit&per_page=100 · Last 12m: 0 | highsource · 2026-10-13 · 90% |
Is Mailpit the right choice for you?
Tell us the job, the constraints and what you weigh most, and we will rank Mailpit against the rest of the email testing dev we index, using the same dated evidence weighted your way.
Free to run, no account needed to start. How the evaluation works
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