MailHog
A local SMTP server for testing email sending during development
- Also known as
- mailhog
What is MailHog?
MailHog is a lightweight testing tool that intercepts emails sent via SMTP and provides a web interface and JSON API to inspect message content, headers, and attachments without delivering them to actual recipients.
MailHog pricing
We don't have MailHog's full plan breakdown yet (its pricing page resisted automated reading). Here's what we could confirm. Always check live pricing for exact numbers.
What MailHog 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
- macOS
- Web
- Linux
- Windows
- On-premise
- Self-hosted
Security & compliance
Known vulnerabilities: 0 (0 in the last 12 months) sourcea count reflects scale & disclosure, not quality
MailHog FAQ
Common questions about MailHog, answered from independent, dated evidence.
What is MailHog?
MailHog intercepts and stores SMTP messages during development, providing a web UI and JSON API for viewing and managing test emails, with the option to forward messages to real mail servers. It is indexed under Email Testing Dev.
Source: https://github.com/pricing
What platforms does MailHog support?
MailHog supports the web, macOS and Linux. Platforms we have not confirmed are simply not listed here rather than ruled out.
Source: https://github.com/pricing
Can MailHog be self-hosted?
Yes. MailHog can be deployed cloud / SaaS and self-hosted, so it does not have to run on the vendor's infrastructure.
Source: https://github.com/pricing
Is MailHog open source?
Yes. MailHog 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.
MailHog 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 MailHog
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 MailHog, not the verdict.
| Signal | Score | Weight | Contribution | Evidence |
|---|---|---|---|---|
| Release cadence | 94 | 0.07 | 6.3 | ✓ |
| Capabilities | 75 | 0.08 | 6.2 | ✓ |
| Stars | 79 | 0.03 | 2.6 | ✓ |
| Dependent projects | 18 | 0.08 | 1.4 | ✓ |
| Security score | 26 | 0.05 | 1.4 | ✓ |
| Integrations | 0 | 0.05 | 0.0 | - |
| Development activity | 0 | 0.12 | 0.0 | ✓ |
| Security posture | 0 | 0.09 | 0.0 | - |
| Package downloads | 0 | 0.17 | 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 | 0 | mediumsource · 2026-08-18 · 65% |
Adoption
Content
| Attribute | Value | Evidence |
|---|---|---|
| Faq | 4 items | mediumsource · 2026-09-10 · 69% |
Features
| Attribute | Value | Evidence |
|---|---|---|
| Capabilities | Open source, Api assertions, Rendering preview, Multi user inboxes, Production sending addon | mediumsource · 2026-10-13 · 60% |
Language
| Attribute | Value | Evidence |
|---|---|---|
| Primary | Go | highsource · 2026-10-13 · 90% |
License
| Attribute | Value | Evidence |
|---|---|---|
| Spdx | MIT | highsource · 2026-10-13 · 95% |
Pricing
Release
Security
| Attribute | Value | Evidence |
|---|---|---|
| Scorecard | 2.6 | highsource · 2026-10-13 · 90% |
| Vulnerabilities | Count: 0 · Source: https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=homebrew&package_name=mailhog&per_page=100 · Last 12m: 0 | highsource · 2026-10-13 · 90% |
| Trust center | https://github.com/security | mediumsource · 2026-10-13 · 60% |
Is MailHog the right choice for you?
Tell us the job, the constraints and what you weigh most, and we will rank MailHog against the rest of the email testing dev we index, using the same dated evidence weighted your way.
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