EmailRelay

Self-Hosted

Lightweight SMTP/POP3 relay and server for self-hosted email workflows

Overview

EmailRelay is an open-source, lightweight mail transfer agent (MTA) supporting SMTP and POP3 protocols. It enables email forwarding between servers, message filtering, and local mail server functionality for small networks or personal use. Easy to deploy via pre-built binaries, Docker, or source code with minimal configuration. Key features include authentication support, filtering rules, and logging for debugging—ideal for users needing a low-resource alternative to heavyweight MTAs like Postfix for specific relay tasks.

Self-Hosting Resources

Find Official Image on Docker Hub View Source & Docs

Below is a reference structure for docker-compose.yml. ⚠️ Do NOT run blindly. Replace placeholders with official values.

docker-compose.template.yml TEMPLATE


version: '3'
services:
  emailrelay:
    image: <OFFICIAL_IMAGE_NAME>:latest
    container_name: emailrelay
    ports:
      - "8080:<APP_INTERNAL_PORT>"
    volumes:
      - ./data:/app/data
    restart: unless-stopped

Key Features

SMTP/POP3 Protocol Compatibility
Message Filtering & Forwarding
Low Resource Footprint

Frequently Asked Questions

? Is EmailRelay hard to install?

No—EmailRelay is easy to install via pre-built binaries for major OSes, Docker images, or source code. Configuration is minimal for basic relay tasks, with simple text files to set up SMTP/POP3 settings and forwarding rules.

? Is it a good alternative to hosted email relay services like SendGrid?

Yes, for users who prefer self-hosted control—EmailRelay lets you manage your own relay without relying on third-party SaaS providers, though it lacks SendGrid’s scalability and advanced analytics.

? Is it completely free?

Yes—EmailRelay is open-source software released under the GNU General Public License (GPL), so it’s free to use, modify, and distribute for any purpose.

Top Alternatives

Microsoft Exchange Server Search Google

IBM Domino Search Google

Tool Info

Pricing Free/Open Source

Category Communication - Email - Mail Transfer Agents

Platform Self-Hosted

Pros

⊕ Lightweight for small-scale deployments
⊕ Open-source (GPL licensed)
⊕ Easy to configure for basic tasks

Cons

⊖ Not suitable for large enterprise use
⊖ Fewer advanced features than Postfix
⊖ Sparse documentation for complex setups