Migrating from Mailgun to Sendpository

Or let your coding agent do the whole migration

Paste it in. It finds every Mailgun call, rewrites it, updates your webhook handler and switches over behind a flag you can flip back.

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Switch this project's email from Mailgun to Sendpository. First run `npx sendpository@latest init` - it opens my browser for me to approve, saves the API key and installs the Sendpository skill - then follow the skill's migration guide (references/migrate.md). If you can't run commands, read https://www.sendpository.com/agents/sendpository/references/migrate.md instead.

1. API differences

2. Authentication differences

3. Domain setup

4. Webhooks

Event names

5. Error handling

6. Code migration

const form = new FormData();
form.append("from", "Acme <billing@mg.yourdomain.com>");
form.append("to", "customer@example.com");
form.append("subject", "Your receipt");
form.append("html", "<p>Thanks for your order.</p>");
form.append("o:tag", "receipt");

await fetch("https://api.mailgun.net/v3/mg.yourdomain.com/messages", {
  method: "POST",
  headers: {
    Authorization: "Basic " + btoa(`api:${process.env.MAILGUN_API_KEY}`),
  },
  body: form,
});

const res = await fetch("https://api.sendpository.com/v1/emails", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.SENDPOSITORY_API_KEY}`,
    "Content-Type": "application/json",
    "Idempotency-Key": "receipt-10428",
  },
  body: JSON.stringify({
    from: "Acme <billing@mail.yourdomain.com>",
    to: ["customer@example.com"],
    subject: "Your receipt",
    html: "<p>Thanks for your order.</p>",
    text: "Thanks for your order.",
    tags: { type: "receipt" },
  }),
});

const body = await res.json();
if (!res.ok) throw new Error(`${body.error.type}: ${body.error.message}`);
console.log(body.id);

Watch out for

• Batch sending with recipient-variables becomes one POST to /emails/batch with a message per recipient - personalise the HTML in your code.
• Stored templates (template with t:variables) have no equivalent; render the HTML before sending.
• The webhook signature moves from the body to a header and covers the raw body, so read the body as text before parsing it.

7. Pricing

8. Things to test before switching

• Re-point anything that used Routes for inbound. Mailgun matches inbound mail with route expressions; ours delivers to an address on your domain and posts an `email.received` webhook, so the matching logic moves into your handler.
• Replace Events API polling. If a job walks Mailgun's events to reconcile state, our webhooks push the same transitions - keep the poller running against both until you trust the webhook path.
• Check for a region prefix. Mailgun's EU accounts use a different API host; there is no equivalent split here, so a hardcoded `api.eu.mailgun.net` has no counterpart to port.

• Send to a real Gmail and a real Outlook address and open Show original: SPF, DKIM and DMARC should all say PASS, with DKIM signed as your own domain.
• Send a message with an attachment and one with an inline image, and check both render.
• Trigger a bounce (an address at a domain you control with no mailbox) and confirm your webhook handler receives email.bounced and marks the address.
• Send the same request twice with one Idempotency-Key and confirm only one email arrives.
• Point a staging environment at the new API key first, and watch the Logs page for 4xx responses before switching production.
• Keep the old provider's DNS records until the new domain has verified and a day of production mail has been delivered - removing them first breaks mail still in flight.

Questions

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