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WhatsApp API
Connect authorized WhatsApp accounts to your applications through the WhatSyncs API. Send messages from a connected number, read synchronized conversations, download media and inspect connection health — all with predictable JSON and bearer-token authentication.
Surface area
There is no object graph to learn. Four resources cover everything most integrations need: messages, conversations, media and connections.
API keys are created in the WhatSyncs dashboard, scoped to your workspace, and can be rotated or revoked. Keys belong on your server — never in a browser bundle or a mobile app.
Multiple numbers
Requests name the connection they act on, so a single integration can send from the sales number, read the support number and monitor both — without juggling separate credentials per number.
API design
Integration work is mostly failure handling. These are the decisions that determine whether your integration survives its first bad week.
One header, scoped keys, rotation without downtime. No signing ceremony for ordinary reads and writes.
Send an idempotency key with a message and a retried request will not send the message twice.
Stable cursors rather than offsets, so a busy conversation does not shuffle results between pages.
Machine-readable error codes with a human-readable message, so failures are diagnosable in logs.
Media is fetched with your key through short-lived download URLs, not from public links.
Reads exist for backfill and reconciliation. For live traffic, subscribe rather than poll.
Send an authenticated POST request to the messages endpoint naming the connection to send from, the recipient and the content. The message goes out from the same business number your team uses.
Text, documents, images and other supported media types are sent the same way — the type field and a media URL are the only difference.
Through webhooks. Register an HTTPS endpoint and WhatSyncs posts each message to it as it arrives, so your CRM is updated in seconds rather than on a polling schedule.
The REST API complements this for backfill and reconciliation: after an outage you can list conversations and confirm that nothing was missed.
Bearer tokens. Every request carries an Authorization header with an API key created in your workspace, over HTTPS.
Keys are workspace-scoped and revocable. Webhook payloads use a separate signing secret so that verifying an inbound event never involves your API key.
No. WhatSyncs is an independent platform that connects to WhatsApp accounts you own and authorize using the standard linked-device flow, and it is not WhatsApp itself or an official WhatsApp product.
That distinction matters when you are choosing an approach, so we state it plainly rather than blurring it.
FAQ
Details that come up during implementation.
Yes. You can send messages from any connected number with an authenticated REST call, which means your CRM, helpdesk or internal application can send from the same number your team uses.
Yes. WhatSyncs is built API-first: authenticated REST endpoints for messages, conversations, media and connections, plus signed webhooks with retries and idempotency keys so events can be processed safely.
Yes. Each business number is a separate connection with its own session, health status and event stream, and all of them are managed from one place. Teams commonly run separate numbers for sales, support, leasing, branches or regions.
Yes. Available media — images, videos, documents and PDFs — is synchronized alongside the conversation data and can be retrieved through the API, so attachments end up on the customer record rather than on one person's phone.
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.
You connect an authorized business WhatsApp account using the standard linked-device flow — the same mechanism you use when pairing WhatsApp with a desktop or web client. Once the session is linked, WhatSyncs keeps it connected and monitors its health.
The Free plan includes full API access, webhooks and three WhatsApp connections.