What it does
Mailosaur is a hosted service for testing email and SMS in software workflows. Teams send test messages to Mailosaur inboxes or numbers, then inspect message content and use its API, SDKs or browser interface to check links, codes, attachments and other outcomes. The service also offers email previews, making it useful for both functional message tests and rendering checks.
Test the message your application sends
Create a Mailosaur inbox and configure a test environment to deliver its email to the inbox's unique address or test domain. The documentation covers sending messages through SMTP and retrieving them through the API, with SDKs and integration guides for tools such as Playwright and Cypress. Assertions can inspect HTML or plain text, links, verification codes, attachments and message properties. This makes Mailosaur useful for checking that a signup or password-reset flow sends the expected message, not just that the browser displayed a success screen.
The service also documents SMS testing, phone numbers and automated authenticator-code workflows. Email previews can help review how a message appears in clients such as Gmail and Outlook. For each test, the application must be configured to send to Mailosaur's test destination; this is not a substitute for delivering messages to real customer inboxes.
Pricing is subscription-based, with monthly and annual billing choices and a 14-day free trial shown on the pricing page. The page varies included inboxes and message allowances by plan. Its published starting amounts use a dollar sign but do not identify the currency or region here, so no exact price is stated.
Strengths
- The same service covers automated email and SMS workflows, including verification-code testing.
- An API, SDKs and framework integrations support assertions against message content, links, codes and attachments.
- Email preview features can show rendering in common mail clients and mobile devices.
Watch out for
- The application must send test messages to Mailosaur inboxes or numbers, so a test environment needs destination-specific configuration.
- Included inbox counts and message volumes vary by subscription tier.
Best for
- QA engineers testing signup, password-reset and verification flows that depend on email or SMS.
- Teams asserting the content, links, codes or attachments in application-generated messages.
- Email teams reviewing rendering across major clients as part of a release check.
Sources
- Mailosaur - email and SMS testing (Oct 25, 2026)
- Documentation | Mailosaur (Oct 25, 2026)
- Email and SMS Testing API | Mailosaur (Oct 25, 2026)
- Sending test email to Mailosaur | Mailosaur (Oct 25, 2026)
- Simple, predictable pricing | Mailosaur (Oct 25, 2026)