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Documentation Index

Fetch the complete documentation index at: https://docs.paubox.com/llms.txt

Use this file to discover all available pages before exploring further.

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Why migrate

HIPAA requires a signed Business Associate Agreement (BAA) with any vendor that handles Protected Health Information (PHI) in transit, including transactional email providers. While Mailgun will sign a Business Associate Agreements (BAAs), itʻs essentially a server-side BAA only. Email in transit over the internet is explicitly excluded from protection obligations, TLS is opportunistic (not enforced), and the customer is held responsible for encrypting PHI. This is the exact gap Paubox closes, email encryption with no fallback to plaintext, regardless of what the recipient’s mail server supports. Paubox is purpose-built for HIPAA compliant email and signs a BAA with every customer. While Mailgun’s API differs from Paubox’s in a few key ways (notably request format and authentication), the concepts map cleanly and the migration is straightforward.

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What stays the same

  • REST API over HTTPS
  • Domain authentication: SPF and DKIM records required
  • SMTP as an alternative to the HTTP API
  • Webhook-based event notifications for delivery status
  • Per-domain sending configuration

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Key differences

DimensionMailgunPaubox Email API
Base URLhttps://api.mailgun.net/v3/YOUR_DOMAIN/messageshttps://api.paubox.net/v1/$PAUBOX_ENDPOINT/messages
EU region URLhttps://api.eu.mailgun.net/v3/YOUR_DOMAIN/messages— no region selection required
Auth methodHTTP Basic Auth — username api, password = API keyBearer token — Authorization: Bearer $PAUBOX_API_KEY
Request body formatmultipart/form-data (-F flags in curl)application/json (JSON body)
Request body shapeFlat fields: from, to, subject, html, textdata.message object with headers and content keys
SMTP hostsmtp.mailgun.orgsmtp.paubox.com
SMTP usernamePer-domain login (e.g. postmaster@yourdomain.com)apikey (literal)
SMTP passwordPer-domain password from Mailgun Control PanelPaubox API key
SMTP port587 or 2525587 (also supports 465, 25)
Webhook eventsaccepted, delivered, opened, clicked, unsubscribed, permanent_fail, temporary_fail, complaineddelivered, opened, temporary_failure, permanent_failure
Batch sendSame endpoint with multiple to recipients or recipient variables/bulk_messages endpoint, recommended max 50 per request
TLS enforcementOptionalAlways-on, cannot be disabled

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Send a single email

curl -s --user 'api:$MAILGUN_API_KEY' \
  https://api.mailgun.net/v3/YOUR_DOMAIN/messages \
  -F from='provider@yourclinic.com' \
  -F to='patient@example.com' \
  -F subject='Your appointment summary' \
  --form-string html='<p>See attached.</p>'
Note:$PAUBOX_ENDPOINT is the username shown on your Paubox Email API > Settings page — not your email address.
Note:Mailgun uses multipart/form-data with HTTP Basic Auth. Paubox uses JSON with a Bearer token. Both the Content-Type header and the request body structure need to be updated.

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SMTP configuration

const transporter = nodemailer.createTransport({
  host: 'smtp.mailgun.org',
  port: 587,
  auth: {
    user: 'postmaster@yourdomain.com', // per-domain SMTP login from Mailgun Control Panel
    pass: process.env.MAILGUN_SMTP_PASSWORD,
  },
});
Tip:Mailgun SMTP credentials are per-domain and found under Sending → Domain Settings → SMTP credentials in the Mailgun Control Panel. Paubox uses the literal string apikey as username and your API key as password — no per-domain credential needed.

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Webhook event mapping

Mailgun eventPaubox event keyNotes
deliveredapi_mail_log_delivered
openedapi_mail_log_opened
permanent_failapi_mail_log_permanent_failure
temporary_failapi_mail_log_temporary_failure
clicked— no equivalentRemove handler or no-op; poll click data via Get message receipt
unsubscribed— no equivalentManage unsubscribes in the Paubox dashboard
complained— no equivalentRemove handler
accepted— no equivalentRemove handler; delivered confirms acceptance
Note:Click tracking is available by polling GET /message_receipt?sourceTrackingId=... — it is not delivered as a push webhook event.
Note:Mailgun webhooks are configured per domain under Sending → Webhooks in the Control Panel, or via the Webhooks API. Paubox webhooks are configured in the Paubox dashboard under Email API → Webhooks.

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Migration checklist

1

Sign a BAA with Paubox

Required before go-live. Contact Paubox to initiate the Business Associate Agreement.
2

Create an account and verify your sending domain

Add your domain on the Paubox Email API > Settings page and complete the TXT record verification. See the Quickstart guide for step-by-step instructions.
3

Generate a Paubox API key

From the Settings page, generate an API key and note your customer endpoint (https://api.paubox.net/v1/YOUR_USERNAME).
4

Update base URL and authentication

Replace the Mailgun domain-namespaced URL and Basic Auth header with the Paubox endpoint and Bearer token.
5

Convert request body from form-data to JSON

Change Content-Type from multipart/form-data to application/json and restructure the body to use the data.message shape shown above.
6

Update SMTP credentials

If you use the SMTP path, update host to smtp.paubox.com, set username to the literal string apikey, and password to your Paubox API key.
7

Remap or remove webhook handlers

Update your webhook endpoint using the event mapping table above. Remove handlers for clicked, unsubscribed, complained, and accepted.
8

Remove any EU region URL overrides

Paubox has a single global endpoint; api.eu.mailgun.net has no equivalent and should be removed.
9

Remove any code that disables TLS

Paubox enforces TLS on every message. Any allowNonTLS: true or equivalent settings should be removed.
10

Send a test message

Confirm delivery using the Get message receipt endpoint with the sourceTrackingId returned from your test send.
11

Swap DNS records

Replace Mailgun SPF/DKIM records with the Paubox records shown in your Settings page.
12

Revoke Mailgun API keys

Once traffic has fully moved to Paubox, revoke your Mailgun API keys and SMTP credentials.

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Next steps

Quickstart guide

Full setup walkthrough from account creation to first send

Webhooks reference

Configure delivery event notifications

Batch send

Send up to 50 messages in a single request

SMTP API

Connect via SMTP instead of REST