GreenMail
An open source sandbox for testing email server protocols without sending actual emails
- Also known as
- greenmail
What is GreenMail?
GreenMail is a lightweight testing tool that simulates SMTP, POP3, and IMAP email servers for application testing. It allows developers to extract, verify, and modify test messages within a contained environment while supporting SSL encryption.
GreenMail pricing
We don't have GreenMail'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 GreenMail 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- Self-hosted
Security & compliance
Known vulnerabilities: 0 (0 in the last 12 months) sourcea count reflects scale & disclosure, not quality
GreenMail FAQ
Common questions about GreenMail, answered from independent, dated evidence.
What is GreenMail?
A testing framework that emulates email server behavior (SMTP, POP3, IMAP) to help developers verify email functionality in their applications during testing, without requiring actual email infrastructure or sending real messages. It is indexed under Email Testing Dev.
Is GreenMail free to use?
GreenMail is open source, so it can be self-hosted and used at no licence cost. It is released under the Apache-2.0 licence. Pricing changes often, so verify at source before relying on it.
Can GreenMail be self-hosted?
Yes. GreenMail can be deployed self-hosted, so it does not have to run on the vendor's infrastructure.
Is GreenMail open source?
Yes. GreenMail is published under the Apache-2.0 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.
GreenMail 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%
- MailSlurpEmail and SMS testing and automation platform with API and dashboard accessmedium · 54%
- MaildevDevelopment email testing utility with SMTP server and web dashboardlow · 35%
- Mailpitlow · 29%
Compare GreenMail
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 GreenMail, not the verdict.
| Signal | Score | Weight | Contribution | Evidence |
|---|---|---|---|---|
| Capabilities | 67 | 0.08 | 5.6 | ✓ |
| Development activity | 47 | 0.12 | 5.6 | ✓ |
| Release cadence | 84 | 0.07 | 5.6 | ✓ |
| Dependent projects | 57 | 0.08 | 4.6 | ✓ |
| Security score | 66 | 0.05 | 3.5 | ✓ |
| Stars | 54 | 0.03 | 1.8 | ✓ |
| Integrations | 0 | 0.05 | 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 | 30 | mediumsource · 2026-10-13 · 65% |
Adoption
Content
| Attribute | Value | Evidence |
|---|---|---|
| Faq | 4 items | mediumsource · 2026-09-10 · 69% |
Features
| Attribute | Value | Evidence |
|---|---|---|
| Capabilities | Open source, Api assertions, Ci cd integration, Multi user inboxes | mediumsource · 2026-10-13 · 60% |
Language
| Attribute | Value | Evidence |
|---|---|---|
| Primary | Java | highsource · 2026-10-13 · 90% |
License
| Attribute | Value | Evidence |
|---|---|---|
| Spdx | Apache-2.0 | highsource · 2026-10-13 · 95% |
Pricing
Release
Security
Is GreenMail the right choice for you?
Tell us the job, the constraints and what you weigh most, and we will rank GreenMail 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
Is this your product?
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