Infrastructure integration

Connect WhatsApp to REST API

The REST API covers messages, conversations, media and connections. Use it to send from a connected number, backfill a customer record, or check the health of a session from your own monitoring.

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REST API

API + webhooks

Available on every plan, including Free.

Implementation

How the REST API connection is built

Four steps. The WhatSyncs side is the same for every destination; the last step is where your system's specifics live.

01
Create an API key in the WhatSyncs dashboard.
02
Authenticate with a bearer token on every request.
03
Send messages, list conversations, download media.
04
Poll connection status, or subscribe to connection events instead.

What you work with

The event in, the request out

Inbound conversations arrive as signed webhook events. Outbound replies are a single authenticated POST from whichever system you decide should send them.

Inbound: whatsapp.message.received

signed

     {          "event"  :     "whatsapp.message.received"  ,          "id"  :     "evt_01H9X2K7Q4ZB3M"  ,          "created_at"  :     "2026-03-04T09:41:07Z"  ,          "connection"  :     {            "id"  :     "conn_sales"  ,            "name"  :     "Sales"  ,            "phone"  :     "+971 4 000 0001"  ,            "status"  :     "healthy"          }  ,          "message"  :     {            "id"  :     "msg_3EB0C9D1A7F2"  ,            "direction"  :     "incoming"  ,            "type"  :     "text"  ,            "text"  :     "I'm interested in the property"  ,            "timestamp"  :     "2026-03-04T09:41:06Z"  ,            "chat"  :     {              "id"  :     "chat_971500000000"  ,              "name"  :     "Amira Khan"  ,              "phone"  :     "+971500000000"            }          }      }

Outbound: POST /messages

201 Created

     curl     https://api.whatsyncs.com/v1/messages     \          -H     "Authorization: Bearer YOUR_API_KEY"     \          -H     "Content-Type: application/json"     \          -d   '  {            "connection"  :     "sales"  ,            "to"  :     "971500000000"  ,            "text"  :     "Hello from WhatSyncs"          }  '

REST API is a trademark of its respective owner. WhatSyncs is an independent platform and is not affiliated with or endorsed by REST API.

FAQ

Integration FAQ

See all questions

Can WhatSyncs connect to my existing CRM?

Yes. WhatSyncs is designed to connect WhatsApp conversations with the CRM and business systems you already use, through webhooks and a REST API. If your CRM can receive an HTTP request or call an API, it can be connected.

Can I use my own in-house CRM?

Yes, and it is one of the most common setups. Custom and in-house systems integrate the same way as commercial CRMs: point a webhook endpoint at WhatSyncs to receive events and call the REST API to send messages or pull conversations.

Can I receive incoming messages through webhooks?

Yes. Incoming and outgoing messages, message status updates and connection events are delivered to your endpoint as they happen. Payloads can be signed so your systems can verify that an event originated from WhatSyncs, and failed deliveries are retried.

How does WhatSyncs avoid duplicate messages?

Every message carries a stable identifier, and WhatSyncs reconciles messages seen through real-time events, reconnects and history synchronization against it. Webhook deliveries also carry an idempotency key so a retry does not create a second record in your CRM.

Other integrations

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Keep reading

WhatsApp CRM integration The general integration page. Read more

Webhooks Event types and signatures. Read more

WhatsApp API Sending and reading. Read more

All integrations Browse the directory. Read more

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{ "event" : "whatsapp.message.received" , "id" : "evt_01H9X2K7Q4ZB3M" , "created_at" : "2026-03-04T09:41:07Z" , "connection" : { "id" : "conn_sales" , "name" : "Sales" , "phone" : "+971 4 000 0001" , "status" : "healthy" } , "message" : { "id" : "msg_3EB0C9D1A7F2" , "direction" : "incoming" , "type" : "text" , "text" : "I'm interested in the property" , "timestamp" : "2026-03-04T09:41:06Z" , "chat" : { "id" : "chat_971500000000" , "name" : "Amira Khan" , "phone" : "+971500000000" } } }

curl https://api.whatsyncs.com/v1/messages \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d ' { "connection" : "sales" , "to" : "971500000000" , "text" : "Hello from WhatSyncs" } '