Resend Email API Emulator

Fully stateful Resend API emulation. Emails, domains, API keys, audiences, and contacts persist in memory. Sent emails are captured and viewable through the inbox UI or the REST API.

No real emails are sent. Accepted calls to POST /emails store the message locally so you can inspect it programmatically or in the browser. Validated sends also record attempts, including recipient rejections.

Start

Local listeners bind to 127.0.0.1 by default. For access from containers or other machines, pass --host 0.0.0.0 to the CLI or hostname: '0.0.0.0' to createEmulator. Configure --base-url or baseUrl for advertised URLs reachable by those clients.

# Resend only
npx emulate --service resend

# Default port (when run alone)
# http://localhost:4000

Or programmatically: