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Gateway

The Gateway is a receive-only SMTP server designed for QA and testing environments. It accepts incoming emails, validates authentication (SPF, DKIM, DMARC, reverse DNS), and stores them with configurable retention.

Key Capabilities

Section titled “Key Capabilities”
  • SMTP Reception: Receive-only server on port 25 with automatic TLS via Let’s Encrypt
  • Email Authentication: SPF, DKIM, DMARC, and reverse DNS validation (configurable per inbox or globally)
  • Spam Analysis: Optional Rspamd integration for spam detection with per-inbox control
  • Chaos Engineering: Simulate delivery failures (latency, errors, connection drops, greylisting, blackhole) to test resilience
  • Configurable Encryption: Quantum-safe encryption (ML-KEM-768) by default, with optional plain storage mode
  • Web Interface: Angular-based UI at /app for viewing emails and authentication results
  • REST API: Programmatic access to emails with auto-generated API keys
  • Webhooks: Real-time HTTP notifications for email events with cryptographic signatures
  • Configurable Retention: Default 7-day TTL, adjustable via environment variables

Architecture

Section titled “Architecture”

The Gateway runs as a single container with two integrated components:

  • Backend (NestJS): SMTP server, certificate management, REST API, serves the frontend
  • Frontend (Angular): Email viewer, authentication results display, inbox management
┌─────────────────────────────────────┐
│  Frontend (Angular)                 │
│  - Served at /app                   │
│  - API calls via /api               │
└──────────────┬──────────────────────┘
               │ HTTP(S)
┌──────────────▼──────────────────────┐
│  Backend (NestJS)                   │
│  - REST API (/api)                  │
│  - SMTP Server (port 25)            │
│  - Let's Encrypt certificates       │
└─────────────────────────────────────┘

Requirements

Section titled “Requirements”
  • Public IP with ports 25, 80, and 443 accessible
  • DNS control for your testing domain (A record + MX record)
  • Docker (recommended) or Node.js 18+
Section titled “Links”

Next Steps

Section titled “Next Steps”