Most applications evaluating a new email service already have working code. The useful question is not just “How do I send my first message?” It is “What needs to change in the integration I have, and what should I preserve?” Our migration library is organised around that question.
Start from the source provider
The library includes guides for Resend, SendGrid, Postmark, Amazon SES, Mailgun, Brevo, Mailjet, SparkPost, SMTP2GO, SMTP.com, Elastic Email, ZeptoMail, Mandrill and Mailtrap. Each starts from the source workflow and points toward Sendar's REST integration.
Use the guide that matches your current service, then compare it with the fields and features your application actually uses. Provider names alone are not a compatibility test. Two applications using the same service can depend on very different parts of it.
Read the limitations before the example
Template formats, SMTP-only applications, inbound processing and custom features may need additional work or may not map to Sendar's current capabilities. The guides call out boundaries rather than presenting every migration as a credential swap.
These are documentation-reviewed mappings, not a claim that every source-provider account has been exercised in a live migration. In particular, the SMTP.com resource is an SMTP-to-REST planning guide where a current API mapping could not be verified.
Use the supporting tools
The language quickstarts show the destination request format. The Next.js starter lets you inspect a message locally before enabling a controlled send. The domain checker provides public authentication-record observations to help investigate setup.
Each tool answers a specific question. A local preview does not prove delivery, and a DNS snapshot does not establish inbox placement. Combine the evidence with your application's own tests and message history.
Move one workflow, then evaluate
Choose a bounded pilot, preserve recipient suppression decisions and assign one sending provider to each event. Keep a rollback rule and the relevant logs. After the pilot is understood, expand deliberately. The library should make that process easier to plan, while leaving the final compatibility decision grounded in the application you operate.