Documentation

NextMail is a self-hostable email platform. These docs cover the developer surface — the REST API, SMTP relay, webhook contract, and the official SDK. For platform architecture and roadmap, see the repository.

Getting started

Add a sending domain, issue an API key, send your first email — all in under ten minutes.

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API reference

Every endpoint, every field. POST /v1/emails, templates, suppressions, webhooks, keys.

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Webhooks

Receive delivery, bounce, open, click events. HMAC verification + retry semantics.

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SDKs

Node/TypeScript today. PHP and Python on the roadmap. Or use the REST API directly.

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Conventions

Base URL. Production is https://api.nextmail.io/v1/. Self-hosted instances expose the same paths under your domain.
Authentication. Send Authorization: Bearer nm_… with every request. Keys are tenant-scoped.
Versioning. The path includes the major version. We will never break /v1/ — breaking changes ship under /v2/.
Rate limits. 300 req/min per API key on the free plan; higher on Pro. Response includes X-RateLimit-Remaining.