WhatsApp API for developers

What the API solves for you

• Outbound queue with retries: a send is acknowledged with 202 and delivered to Meta at each number's pace. A rejection from Meta lands in the message status with a stable code.
• Idempotency: the Idempotency-Key header keeps a retry from sending the same message twice.
• Signed webhooks with HMAC over timestamp and body (replay protection), plus an optional static header for no-code tools such as n8n.
• Templates: create them, sync them and validate them before sending them to Meta, with the reason and the fix when something would be rejected.
• Media: send image, document, audio and video by link, and download incoming media through a proxy.
• Meta errors translated into a catalog of stable codes, with what to do in each case.

What it looks like

A send is an HTTP request with your API key. The number comes from the connection id (conn_…) that GET /v1/connections returns.

Copy-ready examples in cURL, Node.js, PHP and Python: Send a message. The whole contract: OpenAPI.

What it does not do

• It is not a chat inbox for a team: that is WAIA, our turnkey product.
• It does not store files: to send a file of your own, you host it and send the link.
• It does not take you out of Meta's rules: the 24-hour window, approved templates and sending limits still apply. We explain them in Before you connect.

What it costs

A flat fee per connected number, with no message cap. You start with a 14-day trial; the smallest plan is Starter (US$ 12 per month).

• Starter — US$ 12 per month, 1 number
• Studio — US$ 25 per month, 5 numbers
• Agencia — US$ 45 per month, 12 numbers
• Escala — US$ 99 per month, 30 numbers, plus US$ 3 for each extra number

Meta bills its messages separately, to your card; we add no markup. Compared with a provider that does: WAIA Connect vs Twilio.

Frequently asked questions

Does it use Meta's official API?

Yes. WAIA Connect is a Meta-verified technology provider and runs the Cloud API and Coexistence. It does not use unofficial libraries that emulate WhatsApp Web.

How do I receive incoming messages?

You register an https URL and they arrive by POST, signed with HMAC. The signature verification guide has examples in four languages.

What happens if I send the same request twice?

With the same Idempotency-Key the message is sent once and the second response returns the same id.

Is there a monthly message limit?

Not in WAIA Connect: the plan is paid per connected number. Meta has its own limits for starting conversations with templates, which depend on your Meta account.

Is the documentation meant to be read with an AI?

Yes: every module is also in Markdown, there is an llms.txt at the site root, and the full contract is in OpenAPI.

Keep reading

• Documentation
• Authentication
• Receive the webhook
• Error catalog
• WhatsApp Coexistence
• For agencies