sj26/mailcatcher
Mailcatcher
Mailcatcher is a local email development proxy and SMTP server mock designed to intercept outgoing emails during development. It acts as a network bridge that catches outbound mail on a specified port and displays it in a web-based inspector instead of delivering messages to real recipients.
The tool provides a web-based email viewer for reviewing HTML, plain text, and raw source content, along with an interface for inspecting headers and downloading attachments. It utilizes a RESTful JSON API to serve captured mail as structured data to the browser interface.
The system includes a TCP socket-based listener for SMTP interception, in-memory message storage for rapid retrieval, and configurable network bindings for various environments. It can be executed as a foreground process or a background daemon.
Features
- SMTP Message Interception - Acts as a mock SMTP server that intercepts all outgoing mail to prevent delivery to real recipients.
- SMTP Server Mocks - Provides a local SMTP server mock that intercepts outgoing mail for development and testing purposes.
- In-Memory Data Stores - Uses a volatile in-memory data store to hold captured emails for rapid retrieval without a persistent database.
- Local Email Development Proxies - Acts as a network bridge that catches outbound mail and serves it as structured data via web endpoints.
- SMTP Testing Interfaces - Provides a developer-focused interface for intercepting and verifying outgoing SMTP mail content and headers.
- Email Inspection Dashboards - Ships a web-based dashboard for reviewing HTML, plain text, and raw source of captured messages.
- Mock SMTP Servers - Provides a local fake SMTP server to test application mailing features without needing a live internet connection.
- Outgoing Mail Inspection - Captures and analyzes the raw source and attachments of outgoing emails to debug delivery logic.
- TCP and Unix Socket Listeners - Maintains an open TCP socket listener to accept and process incoming SMTP traffic in real time.
- Email Testing Tools - Intercepts and stores all outgoing SMTP mail for review, preventing delivery to actual recipients.
- Email Development - Facilitates the email development workflow by allowing layouts to be reviewed in a browser before production.
- Visual Inspection Tools - Ships a web-based inspector for reviewing the HTML, plain text, and raw source of intercepted emails.
- REST APIs - Exposes captured email data through a RESTful JSON API for use by the web interface.
- Client Side Rendering - Implements a browser-based frontend that fetches data from the API to render email content and headers.
- Email Infrastructure - Listed in the “Email Infrastructure” section of the Awesome Selfhosted awesome list.
- Email Servers - SMTP gateway for debugging and development.
- Web Applications - Captures and views emails in a web interface.
