Quickstart

Your Linq contact gives you an API key during onboarding.

export BASE_URL="https://whatsapp.messages.api.linqapp.com"
export API_KEY="sk_live_…"        # use the exact key issued to you

The OpenAPI document and individual message-part schemas are public:

curl -s "$BASE_URL/v1/openapi.yaml" -o openapi.yaml
curl -s "$BASE_URL/v1/parts/text" | jq .

Open the stream before sending so you see each transition:

curl -N \
  -H "Authorization: Bearer $API_KEY" \
  "$BASE_URL/v1/streams/events"

Persist each SSE id as a resume cursor. The event envelope contains the chat and the range that moved, not message content; read content from the chat journal. Unknown event kinds must be ignored so additive events do not break your consumer.

POST /v1/messages lets Linq select the eligible line and chat for a destination. Supply an idempotency key for every logical send.

curl -sS -X POST "$BASE_URL/v1/messages" \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: first-message-001" \
  -d '{
    "to": "+15551234567",
    "parts": [{"type": "text", "body": "Hello from Linq"}]
  }' | jq .

HTTP 202 means the send is durably accepted. It does not mean delivered. Watch for message.delivered, message.read, or message.failed, then read the addressed range from GET /v1/chats/{chat}/events.

Resume SSE with Last-Event-ID, or page the same durable account sequence:

curl -sS \
  -H "Authorization: Bearer $API_KEY" \
  "$BASE_URL/v1/event_log?limit=100" | jq .

Use the response’s opaque next_cursor on the next request. Keep account-event cursors separate from per-chat sequence cursors.

Next, read Sending messages and Events and recovery.