About Mailosaur
Overview
Mailosaur is an email and SMS testing platform that lets teams validate every customer communication before it reaches a real inbox. Teams create secure test inboxes and dedicated phone numbers to exercise sign-up, password reset, OTP, and MFA flows end to end. Customers have tested over 333 million emails and 7 million SMS messages on the platform across more than 14 years.
Key Benefits
- Verify email content, layout, links, and flows end to end before messages hit real inboxes.
- Test OTPs, MFA codes, and transactional messages with dedicated numbers and secure delivery.
- Generate email previews on real devices across clients, dark mode, and form factors.
- Automate message testing with flexible APIs and native integrations for Cypress, Selenium, and Playwright.
- Validate email accessibility against recognized standards and reduce compliance risk.
- Simulate edge cases like bounces, out-of-office replies, and server errors with configurable rules.
How It Works
Teams send an email or SMS into a Mailosaur inbox or number, then fetch the message through the Mailosaur API. With a few lines of code, testers assert on subject lines, links, and content within their existing testing framework. The same dashboard supports manual checks and email previews, and results flow straight into CI/CD pipelines.
Use Cases
- QA engineers run automated end-to-end tests for sign-ups, password resets, and MFA flows.
- Developers integrate message testing into CI/CD pipelines to catch broken message-driven flows before shipping.
- Marketers preview emails across real devices and dark mode and share previews for sign-off before campaigns go live.
- Product managers confirm authentication and transactional journeys behave correctly before customers rely on them.
- Compliance and design teams validate email accessibility against recognized standards.
Why Choose This Product
Mailosaur combines manual and automated testing in one dashboard, so teams can switch between them for full coverage. It is ISO 27001:2022 certified and GDPR compliant, keeping test messages private and protected. Real devices generate previews rather than emulations, giving accurate results that reflect actual user experience.
Mailosaur Pros & Cons
- Tests email and SMS end to end, including OTPs, MFA codes, and password resets
- Email previews generated on real devices, not emulations
- Native integrations for Cypress, Selenium, and Playwright
- ISO 27001:2022 certified and GDPR compliant
- Proven at scale with over 333 million emails tested
- SMS testing and email previews are paid add-ons on top of the Core plan
Key Features
Email testing
Personal+Send test emails to secure inboxes and verify content, layout, links, and flows end to end before they reach real inboxes.
SMS testing
Test OTPs, MFA codes, and transactional messages using dedicated phone numbers with secure delivery.
Email previews
CoreGenerate previews on real devices showing how emails render across clients, devices, and light and dark modes.
Accessibility checks
CoreValidate email accessibility against universally recognized standards to reduce compliance risk.
Configurable rules
Simulate real-world email behavior like bounces, out-of-office replies, and server errors to test edge cases.
Framework integrations
Automate message testing with native integrations for Cypress, Selenium, and Playwright.
API automation
Fetch messages and assert on subjects, links, and content through the Mailosaur API in a few lines of code.
Security compliance
ISO 27001:2022 certified and GDPR compliant with strict data controls keeping test messages private.
Mailosaur Pricing
View full pricing →- 1 user, with support for up to 3 users
- 1 inbox with unlimited email addresses
- Each inbox has a unique domain name
- From 15,000 inbound emails/month (500 per day)
- Email compatibility testing API for test automation
- Forward individual emails to external addresses
- Everything in Personal
- Team access with 5 seats included
- Multiple inboxes, each with unlimited email addresses
- From 75,000 inbound emails/month (2,500 per day)
- Email accessibility testing and mail rules/auto-forwarding
- POP3 & IMAP connectivity plus reply/send to external addresses
- Custom users and inboxes
- Separate permissions for each team or project
- Single Sign-On (SSO) with SAML2 and OIDC
- Enterprise security features including SCIM
- Advanced support and SLAs with account manager
| Feature | Personal $20/mo | Core $50/mo | Enterprise Custom |
|---|---|---|---|
| Email testing | |||
| Email previews | |||
| Accessibility checks |
Pricing extracted from the product website and may change. Check the source for current details.
Frequently asked questions about Mailosaur
Can I test both email and SMS with Mailosaur?
Yes. Mailosaur provides secure inboxes for email testing and dedicated phone numbers for SMS testing, covering OTPs, MFA codes, and transactional messages with secure delivery.
Can Mailosaur be used for automated email and SMS testing?
Yes. Mailosaur offers flexible APIs and native integrations for Cypress, Selenium, and Playwright, and works with any testing language or framework so teams can automate message tests in code and integrate them into CI/CD pipelines.
Is Mailosaur only for engineers and QA teams?
No. Mailosaur is built for every team that touches communications, including quality assurance, marketers, developers, and product managers, with tools for automated testing, manual checks, and email previews.
What are Mailosaur email previews and how do they differ from emulated screenshots?
Mailosaur generates previews on real devices rather than inaccurate emulations, showing how emails render across email clients, devices, and light and dark modes to reflect authentic user experience.
Can I test accessibility with Mailosaur?
Yes. Mailosaur validates email accessibility against universally recognized standards and checks that HTML does not affect how emails render across specific clients, helping reduce compliance risk.
Can Mailosaur test authentication flows like OTP, MFA, and password resets?
Yes. Teams use Mailosaur to test secure features protected by two-step verification or MFA, including one-time codes, magic links, and password reset flows, instead of skipping tests for those areas.