Email API — PostedApi

Under the hood

One POST. That's the whole integration.

Send a JSON document, get a JSON document back. The response shape never changes between languages or SDKs.

terminal

# Send a single email with curl
curl "https://api.postedapi.org/email" \
  -X POST \
  -H "Accept: application/json" \
  -H "Content-Type: application/json" \
  -H "X-PostedApi-Server-Token: your-server-token" \
  -d '{
    "From": "[email protected]",
    "To": "[email protected]",
    "Subject": "Your receipt is ready",
    "TextBody": "Thanks for your order — details attached.",
    "MessageStream": "outbound"
  }'

# → 200 OK, usually in a couple hundred milliseconds
{
  "MessageID": "c6a4f9b2-7d1e-4a55-9c08-2f8e6b41d903",
  "SubmittedAt": "2025-06-12T14:03:11Z"
}

Copy, paste, send. Your first email can be in the air in under five minutes.

Errors

Error messages that actually help

A 422 should read like a colleague wrote it, not like a server sneezed. Every error carries a status you already know, a sentence that tells you what to fix, and a debug ID our support team can act on the moment you paste it into a ticket.

Precise error codes that map to exactly one cause
Actionable messages that say how to fix the problem
A unique debug ID on every single response

See the error format

Batch sending

Up to 500 messages per call

Firing a whole digest run or onboarding sequence? Shove it into a single request. Each message inside the batch is validated on its own, so one mistyped address never takes the other 499 down with it.

Up to 500 messages in one API call
Individual validation for every message in the batch
A per-message result you can act on, success or failure

Read about batch sends

Sandbox mode

Rehearse everything, send nothing

Every account ships with a sandbox stream. Point your code at it and practise the entire integration — sends, bounces, errors, webhooks — while real inboxes stay gloriously untouched. Flip one setting and the exact same code talks to production.

Test sends, bounces and errors without delivering a thing
Responses identical to production, down to the field names
Go live by swapping one token — no code changes

How the sandbox works

Built for builders

The API is the whole product

No dashboard-first afterthought here. Every feature ships in the API on day one.

JSON in, JSON out

Post a JSON document, get a JSON document back. The request and response shapes are the same in every SDK, every language, every time.

Official SDKs

Node.js, PHP, Python, Ruby, C# and Go. Maintained by us, versioned properly, and boring in the best possible way.

Stats API

Pull delivery rates, bounce counts and engagement numbers straight into your own dashboards with a tidy stats endpoint.

Try the API in minutes

Sign up, grab a server token, and send your first email before your coffee gets cold. The $1.90 Starter plan includes 100 emails a month.

Start for $1.90 Browse the API reference

A REST API built for email