MailcrateAPI & SDKs
Send transactional and templated email from your own systems, and react to what happens next.
Mailcrate's public REST API lives under https://api.mailcrate.io/public/. Every request is authenticated with a workspace API key carrying fine-grained scopes, so a key that only sends mail cannot read your contact list.
Send your first email
Send a template to one recipient. The recipient is found or created by contactEmail, and data fills the template's variables:
curl -X POST https://api.mailcrate.io/public/sending/mail \
-H "Authorization: Api-Key $MAILCRATE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"contactEmail": "ada@example.com",
"templateId": "password-reset",
"lane": "transactional",
"data": { "resetUrl": "https://app.example.com/reset/8f2c" },
"idempotencyKey": "reset-8f2c"
}'Set the lane for transactional mail
A send by templateId or inline html defaults to the marketing lane, which honours unsubscribes and the frequency cap. Password resets, receipts and other mail the recipient asked for need "lane": "transactional". Sends through a transactional message (transactionalMessageId) default to the transactional lane.
idempotencyKey makes the call safe to retry: a second request with the same key returns the original delivery instead of sending twice.
New to the API? The Quickstart takes you from an empty workspace to a delivered email in about five minutes.
Where to go next
Quickstart
Send your first email in about five minutes.
Sending Transactional Email
Recipients, content, lanes, retries and errors.
Send with a Template
Design once in Mailcrate, fill in your data at send time.
Lanes
Why a template send needs lane: transactional.
Templates as Code
React Email components, pushed from your repository.
Batch Sending
Up to 500 emails in one request.
Authentication
Create a key and prove it works in one request.
API Keys & Scopes
Give each key only the scopes its integration needs.
Errors
One error shape on every endpoint, and how to read it.
Rate Limits
Per-key budgets, the headers, and how to back off.
Pagination
Page through lists with limit and offset.
Webhooks
Signed callbacks for bounces, unsubscribes and journeys.
SDKs & Client Libraries
Plain HTTP, or a typed client generated from the spec.
CLI
Push React Email templates from your repository.
Remote MCP
Give an AI agent scoped access to a workspace.
API Reference
Every endpoint, generated from the API.