Best Email Testing Software in 2026
Updated
In short: Emailens is ranked #1 of 28 as of 4 October 2026, ahead of Mailpit and MailSlurp. The best-ranked option with a free plan is Mailpit. The lowest first paid tier on this page is SMTP Labs at $7/mo.
Email testing software helps teams review how messages render and function before sending. Compared on, the entries cover email-client and device coverage, inbox testing, spam checks, and link checks. Accessibility checks and API access may also matter for your review process or integrations, while free-plan availability and paid-from pricing help with cost comparisons. The ranking begins with Emailens, GlockApps, and MailSlurp, followed by Litmus and Mailosaur. Match the listed checks and coverage to the tests your workflow calls for, and use the order as a starting point for comparing options.
28 email testing software ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
Email Testing Software, one module each. A lit port is something its maker publishes; 10 of the 25 on this page have a public API.
- 01 Emailens API yesOSS not on recordFREE yesDOCS 7.4$9/mo
- 02 Mailpit API yesOSS not on recordFREE yesDOCS 7.4Free
- 03 MailSlurp API yesOSS not on recordFREE yesDOCS 7.4$19.99/mo
- 04 Mailtrap Email Sandbox API yesOSS not on recordFREE yesDOCS 7.4$17/mo
- 05 GlockApps API yesOSS not on recordFREE yesDOCS 7.3$59/mo
- 06 SMTP Labs API yesOSS not on recordFREE yesDOCS 7.3$7/mo
- 07 MailHog API yesOSS not on recordFREE yesDOCS 7.2Free
- 08 Litmus API yesOSS not on recordFREE not on recordDOCS 6.8$99/mo
- 09 Mailosaur API yesOSS not on recordFREE not on recordDOCS 6.8$20/mo
- 10 MailCatcher API yesOSS not on recordFREE not on recordDOCS 6.7
- 11 Twilio Segment API not on recordOSS not on recordFREE yesDOCS 6.0$120/mo
- 12 Mailgun API not on recordOSS not on recordFREE yesDOCS 5.7Free
- 13 Twilio Email Testing API not on recordOSS not on recordFREE not on recordDOCS 5.5$15/mo
- 14 Inbox Monster API not on recordOSS not on recordFREE not on recordDOCS 5.4$312.50/mo
- 15 SendForensics API not on recordOSS not on recordFREE not on recordDOCS 5.4$49/mo
- 16 EmailQA API not on recordOSS not on recordFREE not on recordDOCS 5.2
- 17 Mailinator API not on recordOSS not on recordFREE not on recordDOCS 5.2
- 18 RenderOps API not on recordOSS not on recordFREE not on recordDOCS 5.2
- 19 Postdrop API not on recordOSS not on recordFREE not on recordDOCS 5.1
- 20 Testi@ API not on recordOSS not on recordFREE not on recordDOCS 5.1
- 21 testmail.app API not on recordOSS not on recordFREE not on recordDOCS 5.1
- 22 Email Accessibility API not on recordOSS not on recordFREE not on recordDOCS 5.0
- 23 Email Preview Services API not on recordOSS not on recordFREE not on recordDOCS 5.0
- 24 MailTester API not on recordOSS not on recordFREE not on recordDOCS 5.0
- 25 smtp4dev API not on recordOSS not on recordFREE not on recordDOCS 5.0
Is your platform on this list?
Numbered spots on this list can be sponsored. They are labelled, and the editorial order and scores never change for payment.
Questions about this list
Which email testing software is ranked first on Inferse?
Emailens is ranked #1 of 28 with a score of 7.4. Mailpit is second and MailSlurp third.
How many of these have a free plan?
9 of the 25 on this page publish a free plan on their own pricing pages.
Which is the cheapest paid option?
On this page, SMTP Labs has the lowest first paid tier we found: $7/mo.
How is this list ranked?
Ranked on what each maker publishes, open and connectable first: a public API, open-source code, the depth of its documentation and a free tier to try it on. Model lists are sorted by the figure in their title, exactly as each provider publishes it. Paid placements never change a rank.