marlonb/mailcrab repository overview

⁠MailCrab

Email test server for development, written in Rust.

Inspired by MailHog⁠ and MailCatcher⁠.

MailCrab was created as an exercise in Rust, trying out Axum⁠ and functional components with Yew⁠, but most of all because it is really enjoyable to write Rust code.

⁠TLDR

docker run --rm -p 1080:1080 -p 1025:1025 marlonb/mailcrab:latest

⁠Features

• Accept-all SMTP server
• Web interface to view and inspect all incoming email
• View formatted mail, download attachments, view headers or the complete raw mail contents
• Runs on all amd64 and arm64 platforms using docker
• Just a 7.77 MB docker image

⁠Technical overview

Both the backend server and the fontend are written in Rust. The backend receives email over an unencrypted connection on a configurable port. All email is stored in memory while the application is running. An API exposes all received email:

• /api/messages return all message metadata
• /api/message/[id] returns a complete message, given its id
• /ws send email metadata to each connected client when a new email is received

The frontend initially performs a call to /api/messages to receive all existing email metadata and then subscribes for new messages using the websocket connection. When opening a message, the /api/message/[id] endpoint is used to retrieve the complete message body and raw email.

The backend also accepts a few commands over the websocket, to mark a message as opened, to delete a single message or delete all messages.

⁠Installation and usage

To run MailCrab only docker is required. Start MailCrab using the following command:

docker run --rm -p 1080:1080 -p 1025:1025 marlonb/mailcrab:latest

Open a browser and navigate to http://localhost:1080⁠ to view the web interface.

The default SMTP port is 1025, the default HTTP port is 1080. You can configure the SMTP and HTTP port using environment variables (SMTP_PORT and HTTP_PORT), or by exposing them on different ports using docker:

docker run --rm -p 3000:1080 -p 2525:1025 marlonb/mailcrab:latest

Usage in a docker-compose.yml file:

version: "3.8"
services:
    mailcrab:
        image: marlonb/mailcrab:latest
        ports:
            - "1080:1080"
            - "1025:1025"
        networks: [default]

⁠Development

Install Rust⁠ and Trunk⁠

# clone the code
git clone [email protected]:tweedegolf/mailcrab.git

# start the backend
cd backend
cargo run

# serve the frontend (in a new terminal window)
cd ../frontend
trunk serve

# optionally send test messages in an interval
cd ../backend
cargo test