Developer-first WhatsApp API

Everything you need to integrate WhatsApp

Vesper provides a complete set of APIs and tools to send messages, manage sessions, receive webhooks, and build WhatsApp-powered experiences.

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Simple, powerful REST API

Send text, images, videos, documents, and location messages through a clean RESTful interface. Authenticate with a single API key and start sending messages in under 5 minutes.

  • JSON request/response format
  • Bearer token authentication
  • Comprehensive error codes
  • Rate limiting with clear headers
  • Batch messaging support
REST API
curl -X POST https://api.vespergateway.com/api/v1/messages/send/text \
  -H "Authorization: Bearer vsp_1a2b3c4d5e6f" \
  -H "Content-Type: application/json" \
  -d '{
    "sessionId": "my-session",
    "to": "905551234567",
    "text": "Hello from Vesper!"
  }'

Instant event delivery

Receive real-time notifications for all WhatsApp events — incoming messages, delivery receipts, read receipts, session status changes, and group events. Every webhook is HMAC-signed for security.

  • Message received / sent / delivered / read
  • Session connected / disconnected
  • Group join / leave events
  • HMAC-SHA256 signature verification
  • Automatic retry with exponential backoff
Real-time Webhooks
curl -X POST https://api.vespergateway.com/api/v1/apps/:appId/webhooks \
  -H "Authorization: Bearer vsp_1a2b3c4d5e6f" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://yoursite.com/webhook",
    "events": ["message.received", "message.sent"],
    "secret": "your-webhook-secret"
  }'

Manage multiple WhatsApp numbers

Connect and manage multiple WhatsApp numbers simultaneously. Each session operates independently with its own QR code pairing, auto-reconnect logic, and health monitoring.

  • Connect up to 50 sessions per account
  • QR code pairing via API or dashboard
  • Automatic reconnection on disconnect
  • Per-session health monitoring
  • Session status webhooks
Multi-Device Sessions
# Create a new session
curl -X POST https://api.vespergateway.com/api/v1/sessions \
  -H "Authorization: Bearer vsp_1a2b3c4d5e6f" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "sales-line",
    "webhookUrl": "https://yoursite.com/webhook"
  }'

Send any media type

Send and receive images, videos, audio files, documents, contacts, and locations. Upload media directly or provide a URL — Vesper handles format conversion and delivery.

  • Images (JPEG, PNG, WebP)
  • Videos (MP4, 3GP)
  • Audio (MP3, OGG, AAC)
  • Documents (PDF, DOCX, XLSX)
  • Location & contact cards
Rich Media Support
curl -X POST https://api.vespergateway.com/api/v1/messages/send/image \
  -H "Authorization: Bearer vsp_1a2b3c4d5e6f" \
  -H "Content-Type: application/json" \
  -d '{
    "sessionId": "my-session",
    "to": "905551234567",
    "url": "https://example.com/photo.jpg",
    "caption": "Check this out!"
  }'

Built for production workloads

Vesper is designed with security at every layer. API keys are hashed at rest, webhooks are HMAC-signed, and all traffic is encrypted via TLS. Role-based access control ensures only authorized team members can manage sessions.

  • TLS encryption on all endpoints
  • API key hashing (bcrypt)
  • HMAC-SHA256 webhook signatures
  • Role-based access control
  • Rate limiting & DDoS protection
Enterprise Security
# Verify webhook signature (Node.js)
const crypto = require('crypto');

function verifySignature(payload, signature, secret) {
  const expected = crypto
    .createHmac('sha256', secret)
    .update(payload)
    .digest('hex');
  return crypto.timingSafeEqual(
    Buffer.from(signature),
    Buffer.from(expected)
  );
}

Monitor everything in real-time

Track message delivery rates, session uptime, webhook success rates, and API usage through the Vesper dashboard. Export reports and set up alerts for anomalies.

  • Message delivery & read rates
  • Session uptime monitoring
  • Webhook delivery success rates
  • API usage & quota tracking
  • Exportable CSV reports
Analytics Dashboard
# Get message analytics
curl -X GET "https://api.vespergateway.com/api/v1/analytics/messages?\
period=7d&sessionId=my-session" \
  -H "Authorization: Bearer vsp_1a2b3c4d5e6f"

# Response
{
  "sent": 4521,
  "delivered": 4498,
  "read": 3876,
  "failed": 23
}

And much more

Every feature you need to build production-grade WhatsApp integrations.

Low Latency

Messages delivered in under 200ms average.

Auto-Reconnect

Sessions automatically recover from disconnects.

Message Templates

Create reusable message templates with variables.

Group Management

Create groups, add participants, send group messages.

Data Privacy

GDPR-ready infrastructure with EU data residency.

Global Infrastructure

Multi-region deployment for low-latency worldwide.

Ready to get started?

Create your free account and send your first WhatsApp message in under 5 minutes.

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