Send a WhatsApp message from an Attio workflow

1. 1Open the Business page and sign in with Meta.
2. 2Pick your number from your Meta Business portfolio. You need admin access to it.
3. 3Wait until it says Connected.

You keep your own number; Meta does not give you one. Every message that starts a conversation must be a template Meta approved, and Meta charges per message at your country's rate. Meta also reviews your business before sending turns on, so allow more than an afternoon.

1. 1Open Developers in your WhatSync dashboard.
2. 2Create a key and keep Send messages ticked.
3. 3Copy it once and store it in your workflow tool's secrets, never in the workflow text.
4. 4Send it as Authorization: Bearer YOUR_API_KEY on every request.
5. 5If a key ever leaks, revoke it in the same place and create a new one.

1. 1Open WhatsApp Manager and the WhatsApp account you connected to WhatSync.
2. 2Open Message templates and create one.
3. 3Choose a category: marketing, utility or authentication.
4. 4Name it in lowercase, like appointment_reminder, and pick the language.
5. 5Write the message with a variable wherever a value changes.
6. 6Add a sample value for every variable. Meta reads them during review.
7. 7Submit it and wait for approval.

• Templates are only needed to start a conversation. Once someone replies, you can answer without a template for 24 hours.
• Write it the way the customer should read it, and say why they are hearing from you.
• Use variables only for what changes: a name, a time, an invoice number, a link.
• One template per purpose.

Check yours first with the free template builder.

1. 01

   Pick the trigger

   Start from something your team already tracks: a new lead, a booking confirmed, an invoice due, a renewal coming up.

2. 02

   Choose the template

   The template name and language in your request must match the approved template in Meta exactly.

3. 03

   Map the phone number

   International format with the country code. No spaces, brackets or local-only numbers.

4. 04

   Fill the variables

   They go in order: the first value in templateParameters fills {{1}}, the second fills {{2}}, and so on.

5. 05

   Send the request

   Your workflow posts to WhatSync with your API key. We check the template and the number, then pass it to Meta.

6. 06

   Catch the updates

   Meta reports what happened to the message. WhatSync saves it and can call your workflow back with a webhook.

POST https://whatsync.app/api/v1/tools/send_message

JSON body, with your key in an Authorization: Bearer header. Confirm the person agreed to hear from you with recipientOptInConfirmed, and give each send a fresh idempotencyKey (a random UUID) so a retry never sends it twice.

curl -X POST "https://whatsync.app/api/v1/tools/send_message" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "idempotencyKey": "6f1c2a9e-3b7d-4e1a-9c55-0d2f8b7a4e10",
    "channel": "business",
    "phoneNumber": "14155550123",
    "templateName": "appointment_reminder",
    "templateLanguage": "en",
    "templateParameters": ["Ava", "Maya from Sales", "Tuesday at 2:00 PM"],
    "recipientOptInConfirmed": true
  }'

• The template name and language must match the approved template in Meta exactly. The language defaults to en_US.
• Templates with an image, video or document header, or a button that needs a value, cannot be sent this way yet.
• The same message to the same person within an hour is refused, so a looping workflow cannot spam someone.
• A success means Meta accepted the message. Delivery is confirmed later.

Every field and error: API quickstart.

1. Stage 1

   Accepted

   Meta took the request

2. Stage 2

   Sent

   It left Meta

3. Stage 3

   Delivered

   It reached the phone

4. Stage 4

   Read

   They opened it

When a message fails, Meta sends a reason with it. We store both, so you can see whether the number was unreachable or the template broke a rule. To update Attio when the status changes, add a webhook for message.status in Developers and point it at your workflow.

It says the connection is not ready

Your number is not fully connected through Meta. Check the Business page in your WhatSync dashboard says Connected.

Meta rejects the send

Nearly always the template. Check it is approved, the name matches character for character, the language code is right, and the number is in international format.

It says the template is not supported

Templates with an image, video or document header, or a button that needs a value, cannot be sent through the API yet. Use a template without them.

The customer never got it

Check the status in WhatSync, or listen for the message.status webhook. Meta sends a failed update when someone is unreachable or the template breaks policy, and we store the reason.

The wrong value shows up in the message

Parameter order. The first value in templateParameters fills {{1}}, the second fills {{2}}, the third fills {{3}}. One off and the name lands where the date should be.

It says the request was sent before

Every send needs its own idempotencyKey. Reusing one tells WhatSync it is the same send, so nothing goes out twice. Generate a fresh UUID for each message.

Still stuck? Email hello@whatsync.app with the template name and the error you got.

• Create message templatesMeta's walkthrough for writing and submitting a template.
• WhatsApp ManagerWhere you create templates, manage numbers and check approvals.
• Template overviewCategories, components, variables and review rules.
• Cloud API getting startedMeta app setup and account connection, from the developer side.
• Platform or Business app?Meta on the difference between the API and the app you download.
• Add a WhatsApp Business accountAdding a WhatsApp account to your Meta Business portfolio.

What Meta charges in your country: WhatsApp Business API pricing calculator.