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Getting Started

Mailzeno is an API-first transactional email platform built for developers who want reliable email delivery without managing their own SMTP infrastructure.

It provides a clean REST API and a fully typed SDK to send transactional emails using your existing SMTP provider — securely and predictably.

Why Mailzeno?

Most email platforms are designed for marketing teams.

Mailzeno is built for backend systems and engineers.

No campaign builders.
No complex dashboards.
Just infrastructure that works.

  • Single POST /api/v1/emails endpoint
  • Fully typed TypeScript SDK
  • Simple API key authentication (no OAuth flows)
  • Built-in rate limiting (minute + daily limits)
  • Idempotency support to prevent duplicate sends
  • Structured JSON error responses
  • Retry handling for transient SMTP failures
  • Open-core architecture

How it works

Mailzeno accepts email payloads via REST API or SDK, validates them, applies rate limits and idempotency checks, and delivers them securely through the @mailzeno/core engine over SMTP.

Each request is:

  • Authenticated via API key
  • Rate limited per key
  • Processed through a retry-safe SMTP layer
  • Logged for delivery tracking and usage analytics
1
Create an Account

Sign up and access your Mailzeno dashboard.

2
Configure SMTP

Add your SMTP provider credentials securely. Credentials are encrypted at rest.

3
Generate an API Key

Create an API key for your backend service.

4
Send Your First Email

Install the SDK or call the REST API to send transactional emails.

Architecture

Mailzeno follows an open-core architecture with two primary packages:

PackageDescription
@mailzeno/clientOfficial TypeScript SDK for interacting with the Mailzeno API
@mailzeno/coreCore SMTP engine (validation, retry logic, connection pooling, delivery)
Open Core

Mailzeno follows an open-core model.
The client SDK and core engine are open source.
The managed SaaS layer includes authentication, rate limiting, abuse protection, and policy enforcement.

Self-hosting documentation is coming soon.

Next steps

Ready to send your first email?

Head to the Quickstart guide to get up and running in under 5 minutes.