Quickstart

Send your first email through useSend in a few minutes. This guide uses the already-provisioned EverJust Team and its verified send.everjust.app domain, so you can go straight to an API call.

Prerequisites

You need three things, all scoped to a single Team (a Team is one tenant — one product, with its own domains and keys):

• An existing Team — EverJust is already created.
• A verified sending domain — send.everjust.app is verified (DKIM, SPF, DMARC, and MAIL FROM all pass).
• An API key — a key with the us_ prefix already exists.

Base URL and auth

All requests go to the self-hosted instance:

https://mail.everjust.app/api/v1

Authenticate with HTTP Bearer using your us_-prefixed key. The header is exactly:

Authorization: Bearer us_xxx

Store the key in your environment so it never lands in source:

export USESEND_API_KEY="us_xxx"

Sandbox and the mailbox simulator

Amazon SES is currently in sandbox mode (production access requested, pending). Until it is granted you can only send to:

• Verified email addresses on the account, or
• The SES mailbox simulator: success@simulator.amazonses.com, bounce@simulator.amazonses.com, complaint@simulator.amazonses.com.

The simulator accepts mail without emailing a real person and drives a deterministic outcome — success@ delivers cleanly, bounce@ produces a hard bounce, complaint@ produces a complaint. That makes it the right target for a first send. Once production access lands, you can send to any recipient.

Send your first email

Send from EverJust <hello@send.everjust.app> to the simulator's success address. A request needs to, from, a subject (or a templateId), and either text or html.

curl -X POST https://mail.everjust.app/api/v1/emails \
  -H "Authorization: Bearer $USESEND_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "success@simulator.amazonses.com",
    "from": "EverJust <hello@send.everjust.app>",
    "subject": "Hello from useSend",
    "html": "<p>Your first email is on its way.</p>",
    "text": "Your first email is on its way."
  }'

npm install usesend-js

import { UseSend } from "usesend-js";

const usesend = new UseSend(
  process.env.USESEND_API_KEY!,
  "https://mail.everjust.app/api/v1"
);

const { data, error } = await usesend.emails.send({
  to: "success@simulator.amazonses.com",
  from: "EverJust <hello@send.everjust.app>",
  subject: "Hello from useSend",
  html: "<p>Your first email is on its way.</p>",
  text: "Your first email is on its way.",
});

if (error) {
  console.error(error);
} else {
  console.log("Queued:", data?.emailId);
}

pip install usesend

import os
from usesend import UseSend

usesend = UseSend(
    os.environ["USESEND_API_KEY"],
    "https://mail.everjust.app/api/v1",
)

result = usesend.emails.send({
    "to": "success@simulator.amazonses.com",
    "from_": "EverJust <hello@send.everjust.app>",
    "subject": "Hello from useSend",
    "html": "<p>Your first email is on its way.</p>",
    "text": "Your first email is on its way.",
})

print(result)

A successful call returns 200 with the email's id:

{ "emailId": "em_3f9c8b2a" }

Check delivery status

Fetch the email by id to see its lifecycle. The emailEvents array records each status transition; for the simulator's success address you'll see it progress from SENT to DELIVERED.

curl https://mail.everjust.app/api/v1/emails/em_3f9c8b2a \
  -H "Authorization: Bearer $USESEND_API_KEY"

{
  "id": "em_3f9c8b2a",
  "teamId": "team_everjust",
  "to": "success@simulator.amazonses.com",
  "from": "EverJust <hello@send.everjust.app>",
  "subject": "Hello from useSend",
  "html": "<p>Your first email is on its way.</p>",
  "text": "Your first email is on its way.",
  "createdAt": "2026-09-01T15:04:05.000Z",
  "updatedAt": "2026-09-01T15:04:07.000Z",
  "emailEvents": [
    { "emailId": "em_3f9c8b2a", "status": "QUEUED",    "createdAt": "2026-09-01T15:04:05.000Z", "data": null },
    { "emailId": "em_3f9c8b2a", "status": "SENT",       "createdAt": "2026-09-01T15:04:06.000Z", "data": null },
    { "emailId": "em_3f9c8b2a", "status": "DELIVERED",  "createdAt": "2026-09-01T15:04:07.000Z", "data": null }
  ]
}

The top-level status is exposed as latestStatus in list responses (GET /v1/emails). The full status enum is: SCHEDULED, QUEUED, SENT, DELIVERY_DELAYED, BOUNCED, REJECTED, RENDERING_FAILURE, DELIVERED, OPENED, CLICKED, COMPLAINED, FAILED, CANCELLED, SUPPRESSED.

Next steps