Postlane

Postlane is a transactional email API. Applications use it to send welcome messages, address verification, password resets, and receipts from a verified domain.

Postlane is not an inbox, and it does not provide IMAP or hosted mailboxes.

• Product: https://www.postlane.email
• Docs: https://www.postlane.email/docs
• Pricing: https://www.postlane.email/pricing
• Sign in: https://www.postlane.email/login

Send

Create a key at API keys after you verify a sending domain. The secret is shown once and starts with pl_live_. Keep it on your server.

POST https://www.postlane.email/v1/emails
Authorization: Bearer pl_live_…
Content-Type: application/json
Idempotency-Key: welcome-user-123

{
  "from": "hello@send.yourdomain.com",
  "to": ["alex@example.com"],
  "subject": "Welcome",
  "html": "<h1>You’re in.</h1>"
}

A successful response is 202 with { "id": "em_…", "status": "queued" }. queued means the message was accepted for delivery. It does not mean the message is in the inbox. Repeating the same Idempotency-Key returns the original result and does not send again.

Errors use { "error": { "code", "message", "request_id", "retryable" } }. The same contract is published for agents at https://www.postlane.email/llms.txt.

Cursor

postlane-cursor/ is the Postlane plugin for Cursor. It teaches POST /v1/emails and exposes send_email, get_email, and list_emails. The API key is a plugin setting. It is not stored in this repository.

Development

npm install
npm run dev

Open http://localhost:5173. The first API request creates the local database schema. Local sends use a mock provider unless Email Sending is bound. accepted in that mode means the request was stored, not delivered.

npm test
npm run typecheck

Signed webhook delivery, attachments, and template versions are not part of the public API yet.