Every service email, one API call.
Receipts, password resets, verification links, notifications, the email your product has to send. Same branded templates, same verified domain, same deliverability as your marketing, on the same contact timeline.
Live now. Point your existing HTML at
POST /v1/send with the API key you already have, and keep the
templates you've written. Read the docs.
Drop your transactional provider.
The same pipe that sends your lifecycle email handles the service messages too, no second vendor, no second integration.
One API call
letter.send() with a subject and a body. No new SDK, no
new keys, it's the client you already installed.
Bring your own HTML
Post the markup you already render. Switching providers is a change of base URL and API key, not a rewrite of your emails.
Safe retries
Pass an idempotency key and a retrying worker returns the original send instead of mailing your customer twice.
Your domain, same delivery
Sends from your verified domain on the same deliverability infrastructure, so critical mail actually arrives.
Bypasses marketing opt-out
Service messages reach everyone, a password reset shouldn't depend on whether someone unsubscribed from your newsletter.
One timeline
Every transactional send lands on the contact's timeline next to their lifecycle and broadcast history. One view of every email.
The email your product must send.
Transactional email isn't optional, it's the receipt, the reset, the verification link a user is waiting on. One call covers all of it, with the reliability those moments demand.
- Account verification and welcome confirmations
- Password resets and magic links
- Billing receipts and invoices
- Usage alerts and product notifications
Marketing and service, one view.
With a separate transactional provider, half a contact's email history lives somewhere you never look. In Letter, the receipt sits right under the onboarding drip and the last broadcast, the whole relationship in one place.
The rest of the pipe.
Every pillar shares the same contacts, templates, and sending infrastructure. Here's what pairs with this one.
One integration.
Every email.
Free up to 1,000 contacts. No credit card. Capture a lead, fire an event, watch it arrive.