Developers

Build on Nexus Connect

REST API for messages, contacts, webhooks, and scheduling. HMAC-signed webhooks for real-time events. Embeddable web chat widget.

Authentication

All API requests require an API key in the Authorization header. Create keys in your dashboard under Settings → API Keys.

Authorization: Bearer nexus_YOUR_API_KEY

Messages API

Send text, media, and template messages via WhatsApp.

POST /api/v1/messages/send

POST /api/v1/messages/send-media

POST /api/v1/messages/send-template

Contacts API

Create, read, update, and delete contacts programmatically.

GET /api/v1/contacts

POST /api/v1/contacts

GET /api/v1/contacts/:waId

PATCH /api/v1/contacts/:waId

Webhooks API

Receive real-time events — HMAC-SHA256 signed for authenticity.

POST /api/v1/webhooks — register subscription

GET /api/v1/webhooks — list subscriptions

Events: message.received, message.status, conversation.ended, contact.updated

Scheduled Messages

Schedule messages for future delivery.

GET /api/v1/scheduled

POST /api/v1/scheduled

Web Chat Widget

Embed a chat widget on any website with a single script tag.

GET /api/v1/widget/sdk.js — embeddable SDK

GET /api/v1/widget/config — widget configuration

POST /api/v1/widget/sessions — create/resume sessions

Feature Flags API

Manage feature flags programmatically — CRUD + evaluation.

GET /api/v1/features

POST /api/v1/features/evaluate

PATCH /api/v1/features/:key

Quick Start Examples

Send a WhatsApp Message

curl -X POST https://connect.insynapse.com/api/v1/messages/send \
  -H "Authorization: Bearer nexus_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "919876543210",
    "type": "text",
    "text": "Hello from Nexus Connect!"
  }'

Verify Webhook Signature

// Verify webhook signature (Node.js)
const crypto = require("crypto");

function verifySignature(rawBody, secret, signatureHeader) {
  const expected = crypto
    .createHmac("sha256", secret)
    .update(rawBody)
    .digest("hex");
  return signatureHeader === `sha256=${expected}`;
}

Embed Web Chat Widget

<!-- Add to your website -->
<script src="https://connect.insynapse.com/api/v1/widget/sdk.js?id=YOUR_WIDGET_ID"></script>

Need help integrating? Talk to our engineering team.

Get API Key