Mailpro APIs | Email API, CRM API & SMS API for your applications

Q: How do I get an API key?

Sign in to your Mailpro account and open Settings → API Settings. You will find your client ID and your API key there. You can call the APIs directly with them, exchange them for a Bearer token via POST /v3/token, or create an OAuth 2.0 application under Settings → OAuth applicationsevent.

Q: Which authentication methods are supported?

Three: the Bearer token (valid 30 days, renewable), theclient ID + API key, and OAuth 2.0 with PKCE (recommended for third-party applications and platforms like Zapier, Make and n8n, with scoped permissions). A single token works across the Email, CRM and SMS APIs.

Three APIs. One platform.

Pick the one you need — or combine all three. REST and JSON, documented endpoint by endpoint on the developer portal.

Email API

Manage your address books and templates, send campaigns and transactional emails, track your statistics. JSON or XML.

→Campaigns & transactional emails
→Delivery status of every single send
→Address books, templates, senders
→Statistics: opens, clicks, countries, bounces

See the Email API docs →

CRM API

Manage your contacts, custom fields, tags and segments — and send email & SMS to those contacts. Webhooks and OAuth 2.0 for third-party tools.

→Contacts, lists, tags & segments
→Email and SMS sending to contacts
→Webhooks: real-time events
→OAuth 2.0 (PKCE) for Zapier, Make, n8n

See the CRM API docs →

SMS API

Send bulk or single SMS worldwide, straight from your application. Number lists and history included.

→Bulk & individual SMS
→International coverage (00 prefix)
→Delivery receipts by webhook (sms.delivered)
→Scheduling and cancellation

See the SMS API docs →

For developers

Modern tooling, no surprises.

Everything you need to deliver integrations fast and run them with confidence.

REST + JSON

Predictable resources, consistent error shapes with a request identifier, standard HTTP verbs and status codes. XML available on the Email and SMS APIs.

Three authentication modes

Bearer token (30 days, renewable), API key, or OAuth 2.0 with PKCE and scoped permissions for third-party applications. HTTPS everywhere.

OpenAPI documentation in 6 languages

Every endpoint described with its parameters, responses and examples; try the calls from the docs. Downloadable OpenAPI specification to generate your client.

Signed webhooks

Email delivered, bounce, open, click, contact created, SMS delivered… pushed to your URL as JSON, signed with HMAC-SHA256, with automatic retries.

Delivery tracking

Every transactional email returns an identifier; query its status (delivered, deferred, bounced) or receive the email.deliveredevent.

Predictable rate limits

500 requests/min per account. Beyond that, a 429 response with X-RateLimit-* and Retry-After headers — no silent throttling.

Use cases

From sign-up emails to international SMS — one integration.

Whether you build a SaaS, an e-commerce platform or an internal tool, our APIs cover all of your product's messaging needs.

Transactional & marketing emails

Welcome emails, password resets, receipts, newsletters and full campaigns — and for every single send, confirmation of handover to the recipient's server.

CRM & contact sync

Keep profiles, tags and segments in sync with your product database; connect Zapier, Make or n8n over OAuth 2.0, or let a webhook notify your tool on every change.

SMS notifications worldwide

Two-factor codes, delivery alerts, appointment reminders — sent worldwide, with delivery receipts by webhook.

POST https://your-server/webhook · email.delivered

200 OK

X-Mailpro-Signature: t=1758000000,v1=5a72…c8b1
X-Mailpro-Event-Type: email.delivered

{
  "id": "evt_5f2c…",
  "type": "email.delivered",
  "created": 1758000000,
  "apiVersion": "v3",
  "account": { "id": 12345, "name": "My company" },
  "data": {
    "email": "[email protected]",
    "idSending": 987654,
    "sendingType": 3,
    "diagCode": "250 2.0.0 OK",
    "deliveredAt": "2026-09-16T08:03:41Z"
  }
}

Developer resources

The technical reference on the portal, practical answers in the FAQ, examples on GitHub.

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Developer portal

The complete documentation of the Email, CRM and SMS APIs: endpoints, parameters, responses, error codes, webhooks and authentication. In English and five other languages.

Open the portal

API & Webhooks FAQ

The three types of webhooks, delivery tracking, signature verification, limits, Zapier / Make / n8n, SMTP or API… explained step by step.

Read the FAQ

Examples on GitHub

An open-source “starter” (MIT licence) with call examples in Node.js, Python, PHP, C# and Java, to adapt to your project.

GitHub

API — frequently asked questions

Quick answers for developers integrating Mailpro. Details are in the API & Webhooks FAQevent.

How do I get an API key?+

Sign in to your Mailpro account and open Settings → API Settings. You will find your client ID and your API key there. You can call the APIs directly with them, exchange them for a Bearer token via POST /v3/token, or create an OAuth 2.0 application under Settings → OAuth applicationsevent.

Which authentication methods are supported?+

Three: the Bearer token (valid 30 days, renewable), theclient ID + API key, and OAuth 2.0 with PKCE (recommended for third-party applications and platforms like Zapier, Make and n8n, with scoped permissions). A single token works across the Email, CRM and SMS APIs.

Are the APIs REST or SOAP?+

They are REST APIs over HTTPS. Responses are JSON (the Email and SMS APIs also support XML, through the .json / .xml URL extension), with predictable resources, standard HTTP verbs and status codes.

Is there interactive documentation or a test mode?+

Yes. The developer portal describes every endpoint (OpenAPI) and lets you try the calls from the documentation. You can send test emails and SMS to your own address before going to production.

Which languages can I use? Is there an SDK?+

Any language that speaks HTTP and JSON. We publish on GitHub an open-source starter with examples in Node.js, Python, PHP, C# and Java, and the portal's OpenAPI specification lets you generate a client in the language of your choice.

Do the APIs support webhooks?+

Yes, in all three directions: Mailpro notifies you of events (email delivered, opened, clicked, bounced, contact created, SMS delivered…) through HMAC-SHA256-signed HTTP calls with retries; your automations can call an external tool (“Send a webhook” action); and an external tool can trigger an automation (incoming webhook). The three types of webhooks explainedevent.

Can I send transactional emails and track their delivery?+

Yes. Send a single email to one recipient with custom fields, attachments and optional scheduling, through the Email API or the CRM API. The send returns an identifier; GET /v3/Send/{id}/Status then tells you whether it is queued, sent, delivered, deferred or bounced (status available about 5 minutes after handover, kept for 365 days). In detailevent.

Can I send file attachments? What are the limits and cost?+

Yes — attach files when you send an email through theEmail API (v2) or the CRM API (v3): up to 5 files, 10 MB per file and 15 MB in total. Send them as Base64-encoded attachments on either API (the Email API also accepts multipart/form-datafile uploads). The cost is 1 credit per 500 KB of attachments, with the first 500 KB included in the email's base credit (so attachments up to ~500 KB add nothing extra). Common document and image formats are accepted; executable and script files (.exe, .bat, .js, .vbs, .msi, .jar, .dll, etc.) are blocked for security.

How does SMS pricing work?+

SMS is credit-based. One SMS costs the destination country's credit price multiplied by the number of parts (a long message is split into several parts). Email sending uses email credits.

Which email address formats are accepted?+

Any RFC-compliant address, including sub-addressing with a “+” (for example [email protected]), which is supported by Gmail, Fastmail, Proton and others.

What are the rate limits?+

500 requests per minute per account. Beyond that, you receive an HTTP 429 response with the X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset and Retry-Afterheaders, so you can back off and retry gracefully. API calls also draw on an API credit quota tied to your email credits.

Send your first request in minutes.

Create a free Mailpro account, grab your API key under Settings → API Settings and start sending — no credit card required.

Create an account — free Read the documentation