---
title: SentFast API
slug: index
description: Send a stored email template from any backend with a single HTTP request.
order: 0
updatedAt: '2026-08-14'
---

The SentFast API sends emails you have already built in the dashboard. Your
backend does not carry subjects, HTML or copy: it sends a template id, a
recipient and the values of the dynamic variables.

Everything runs against one endpoint:

```
POST https://sentfa.st/api/v1/email/send
```

## Before you start

You need three things:

1. A **project workspace**, which owns your templates and your keys.
2. An **email template** created in the dashboard, with its `{{variables}}` defined. Its id looks like `em_a1b2c3d4`.
3. An **API key** for that project. It is shown once, when you create it.

## Send your first email

```
curl -X POST "https://sentfa.st/api/v1/email/send" \
  -H "Content-Type: application/json" \
  -H "x-api-key: $SENTFAST_API_KEY" \
  -d '{
    "id": "em_a1b2c3d4",
    "to": "customer@example.com",
    "params": { "user_name": "Alex" }
  }'
```

A successful call returns:

```json
{ "ok": true, "message": "Email \"em_a1b2c3d4\" queued/sent to customer@example.com" }
```

From then on, changing the wording of that email is an edit in the dashboard.
Your backend keeps sending the same id.

## Machine-readable references

- [openapi.json](/openapi.json): the full specification of the endpoint, for client generators and agents.
- Every page here has a markdown version at the same path with `.md` appended, for example [/docs/send-email.md](/docs/send-email.md).