Introduction

Posta is a self-hosted, open-source email delivery platform that gives developers full control over their email infrastructure. It provides a developer-friendly REST API for sending emails, managing templates, tracking delivery, and monitoring analytics — all without relying on third-party services like SendGrid or Mailgun.

Why Posta?

• Self-hosted — Your data stays on your servers. No vendor lock-in.
• Developer-first — Clean REST API with official SDKs for Go, PHP, and Java.
• Full-featured — Templates with versioning and localization, SMTP management, domain verification, webhooks, analytics, and more.
• Open source — Licensed under Apache 2.0. Contribute, fork, or customize as needed.

Key Features

Feature	Description
Email Delivery	Send single, template, and batch emails via REST API
Templates	Version-controlled templates with multi-language support
SMTP Management	Configure multiple SMTP servers with automatic failover
Domain Verification	SPF, DKIM, and DMARC record verification
Webhooks	Real-time notifications on email events
Analytics	Delivery rates, bounce rates, and latency metrics
Security	API keys, JWT auth, 2FA (TOTP), rate limiting, IP allowlists
Admin Panel	User management, platform metrics, shared SMTP pool
GDPR Compliance	Data export, import, and deletion
Prometheus Metrics	Built-in observability for production monitoring

Architecture

Posta is built with:

• Go backend using the Okapi web framework
• PostgreSQL for persistent storage
• Redis for job queues (via Asynq) and caching
• Vue 3 dashboard (embedded or standalone)

┌─────────────┐     ┌─────────────┐     ┌──────────────┐
│  Your App   │────▶│  Posta API  │────▶│  PostgreSQL  │
│  (SDK/HTTP) │     │  (Go)       │     └──────────────┘
└─────────────┘     │             │     ┌──────────────┐
                    │             │────▶│  Redis       │
                    └──────┬──────┘     └──────────────┘
                           │
                    ┌──────▼──────┐     ┌──────────────┐
                    │   Worker    │────▶│  SMTP Server │
                    │  (Asynq)   │     └──────────────┘
                    └─────────────┘

Next Steps

• Installation — Deploy Posta with Docker or from source
• Configuration — Configure environment variables
• Quick Start — Send your first email in minutes