smtp4dev

With smtp4dev, developers can intercept and examine all outgoing emails from their applications, preventing accidental spam to customers. This dummy SMTP server works on Windows, Linux, and Mac, offering IMAP/POP3 access to retrieve and delete messages, plus OpenAPI/Swagger integration. It logs SMTP sessions, supports UTF8, and includes a viewport switcher for device simulation. Features like multipart MIME inspection, HTML validation, and TLS/SSL with self-signed certs ensure thorough testing. Manage multiple mailboxes with rules, relay messages automatically, and use scripting to simulate errors for robust email handling.