API Documentation — JustEmails

Transactional Email API

Send emails from your verified domains via a simple REST API. Reliable delivery, real-time status tracking, and full DKIM/SPF authentication — all included.

Authentication Endpoints Code Examples Rate Limits Error Codes

Authentication

All API requests must include a Bearer token in the Authorization header. API keys use the je_ prefix.

Authorization: Bearer je_live_abc123...

You can create and manage API keys from the dashboard or via the POST /api-keys endpoint below.

Base URL

https://justemails.app/api/v1

All paths below are relative to this base URL. HTTPS is required.

Endpoints

POST/send

Send a transactional email from a verified domain.

Request body

{
  "from": "hello@yourdomain.com",
  "to": "user@example.com",
  "subject": "Welcome!",
  "html": "<h1>Hello</h1><p>Thanks for signing up.</p>",
  "text": "Hello — Thanks for signing up.",
  "replyTo": "support@yourdomain.com",
  "headers": { "X-My-Tag": "onboarding" }
}

Response

{
  "id": "msg_abc123",
  "status": "queued",
  "from": "hello@yourdomain.com",
  "to": "user@example.com",
  "createdAt": "2026-04-06T12:00:00Z"
}

GET/send/:id

Retrieve the delivery status of a sent message.

Response

{
  "id": "msg_abc123",
  "status": "delivered",
  "from": "hello@yourdomain.com",
  "to": "user@example.com",
  "subject": "Welcome!",
  "createdAt": "2026-04-06T12:00:00Z",
  "deliveredAt": "2026-04-06T12:00:02Z"
}

GET/messages

List sent messages with optional filters.

Response

{
  "data": [ { "id": "msg_abc123", "status": "delivered", ... } ],
  "pagination": { "page": 1, "perPage": 50, "total": 312 }
}

POST/api-keys

Create a new API key.

Request body

{ "name": "Production backend" }

Response

{
  "id": "key_xyz789",
  "name": "Production backend",
  "key": "je_live_abc123...",
  "createdAt": "2026-04-06T12:00:00Z"
}

GET/api-keys

List all API keys for the authenticated account.

Response

{
  "data": [
    { "id": "key_xyz789", "name": "Production backend", "lastUsed": "2026-04-06T11:50:00Z" }
  ]
}

DELETE/api-keys/:id

Revoke an API key. This action is irreversible.

Response

{ "deleted": true }

Code Examples

cURL

curl -X POST https://justemails.app/api/v1/send \
  -H "Authorization: Bearer je_live_abc123..." \
  -H "Content-Type: application/json" \
  -d '{
    "from": "hello@yourdomain.com",
    "to": "user@example.com",
    "subject": "Welcome!",
    "html": "<h1>Hello</h1>"
  }'

Node.js (ES Modules)

import fetch from "node-fetch";

const res = await fetch("https://justemails.app/api/v1/send", {
  method: "POST",
  headers: {
    Authorization: "Bearer je_live_abc123...",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    from: "hello@yourdomain.com",
    to: "user@example.com",
    subject: "Welcome!",
    html: "<h1>Hello</h1>",
  }),
});

const data = await res.json();
console.log(data.id); // "msg_abc123"

Python (requests)

import requests

resp = requests.post(
    "https://justemails.app/api/v1/send",
    headers={
        "Authorization": "Bearer je_live_abc123...",
        "Content-Type": "application/json",
    },
    json={
        "from": "hello@yourdomain.com",
        "to": "user@example.com",
        "subject": "Welcome!",
        "html": "<h1>Hello</h1>",
    },
)

data = resp.json()
print(data["id"])  # "msg_abc123"

Rate Limits

API requests are rate-limited per API key to ensure fair usage and platform stability.

Tier	Limit	Window
Send emails	100 requests	per minute
Read endpoints	300 requests	per minute
Key management	10 requests	per minute

When you exceed the limit you will receive a 429 Too Many Requests response. Use the Retry-After header to know when to retry.

Error Codes

Error responses always return a JSON body with error and message fields.

{ "error": "VALIDATION_ERROR", "message": "The 'to' field is required." }

Code	Meaning	Description
400	Bad Request	Missing or invalid parameters.
401	Unauthorized	Missing or invalid API key.
403	Forbidden	The API key does not have permission for this action.
404	Not Found	The requested resource does not exist.
409	Conflict	Duplicate resource (e.g. sending-domain already exists).
422	Unprocessable Entity	Validation failed (e.g. unverified from domain).
429	Too Many Requests	Rate limit exceeded. Retry after the Retry-After header.
500	Internal Server Error	Something went wrong on our end. Please try again.

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