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Quickstart

Postilon sends transactional email (sign-in codes, receipts, password resets) from your own domain. You can send through the REST API at https://api.postilon.com or through the SMTP relay. This guide takes you from a new account to a delivered email in a few minutes.

1. Create an account

Sign up and confirm your email address. You get a workspace, which holds your domains, API keys, emails and credits.

2. Create an API key

In the dashboard, open API Keys and create a key. A key is shown once, so store it in your secret manager or environment.

  • ps_test_… keys are for development. Emails are accepted, rendered, signed and reported like real ones, but delivery is simulated: nothing leaves Postilon and no credits are used. Any from address works.
  • ps_live_… keys send real mail. They need a verified domain and credits.

Send the key in the Authorization header of every request:

Authorization: Bearer ps_test_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

3. Send an email

curl https://api.postilon.com/v1/emails \
  -H "Authorization: Bearer $POSTILON_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "Acme <hello@acme.com>",
    "to": "jane@example.com",
    "subject": "Your sign-in code",
    "html": "<p>Your code is <strong>482913</strong>.</p>",
    "text": "Your code is 482913."
  }'

Postilon accepts the email and queues it:

{
  "id": "msg_4kQ9wZ2xT7bLmN3pR8sV",
  "status": "queued",
  "from": "Acme <hello@acme.com>",
  "to": ["jane@example.com"],
  "environment": "test",
  "credits_used": 0,
  "scheduled_at": null,
  "created_at": "2026-10-25T10:00:00Z"
}

4. Follow what happens

Fetch the email to see its status and events, or open it in the dashboard under Emails:

curl https://api.postilon.com/v1/emails/msg_4kQ9wZ2xT7bLmN3pR8sV \
  -H "Authorization: Bearer $POSTILON_API_KEY"

To be told about deliveries, bounces and complaints as they happen, add a webhook.

5. Go live

  1. Add and verify your domain. Your first verified domain adds 3,000 free credits to the workspace.
  2. Create a ps_live_ key and use it in production.
  3. Buy credits when you need more: each email to one recipient uses 1 credit, at USD 4 per 10,000. See Pricing.

New workspaces can send to 100 recipients per rolling 24 hours; the limit rises to 10,000 after the first paid top-up. See Errors and limits.

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