WhatsApp Business Calling API for Developers
Go from signup to enabling voice calls in as little as 5 minutes. The secure, scalable, and reliable WhatsApp voice call API for businesses of all sizes.
Get the Power of WhatsApp voice API
WhatsApp Business Calling API allows you to make and receive high-quality voice calls directly within the WhatsApp chat interface. It's a seamless way to escalate a conversation from text to a voice call without leaving the app.
VoIP Technology
All calls are made over the internet, providing a clear and cost-effective communication channel.
Unified Conversation
Keep all your customer interactions—both chat and call logs—in a single, organized thread.
Branded Experience
Your business name, logo, and verified green tick appear on the calling screen, building trust and credibility.
Global Reach
Connect with over 2 billion WhatsApp users worldwide without worrying about international calling fees.
Stop Fighting, Start Building
We handle the undifferentiated heavy lifting of the WhatsApp API so you can focus on your product, not on plumbing.
| Feature | SendZen | Twilio | Other BSPs |
|---|---|---|---|
| Onboarding Speed | Under 5 Mins | Multi-day Setup | Slow, Manual |
| Developer Experience | Best-in-Class SDKs | Generic for many APIs | Raw HTTP only |
| Pricing | Transparent, Pay-as-you-go | Complex Pricing | Hidden Fees |
| Webhook Management | Included & Managed | You Build It | You Build It |
Elevate Your Customer Conversations
From resolving issues faster to closing high-value deals, voice calls can transform your customer engagement.
Close Deals Faster
Seamlessly switch from chat to a voice call to handle objections, build trust, and close high-value sales in real-time.
Resolve Complex Issues
For complicated support queries, a quick call can be more effective than a long chain of messages, leading to faster resolutions and happier customers.
Centralize Communication
Manage all your customer interactions in one place. No more switching between your phone system and your messaging platform.
Cost-Effective Solution
With free incoming calls and competitive per-minute rates for outgoing calls, it's a leaner, cheaper alternative to traditional phone systems.
Get Started in 3 Simple Steps
Our developer-first approach means you can get up and running in minutes.
1. Sign Up & Get Your API Key
Complete the WhatsApp Embedded Signup process to instantly get your API key.
2. Enable Voice Calling
Activate the voice calling feature for your number with a single API call or a toggle in your dashboard.
3. Make & Receive Calls
Use our intuitive SDKs to start making and receiving calls. We provide detailed documentation for Node.js, Python, and more.
Features of SendZen's WhatsApp Business Calling API
Everything you expect — voice calling, routing, automation, analytics.
Inbound user-initiated calls
Any WhatsApp user can call your business number via the call button or deep link.
Outbound business-initiated calls
You can call WhatsApp users (where permitted) using your business WhatsApp number via API.
Unified chat + voice thread
Your system retains chat history, call logs in the same conversation context.
Full telemetry & metrics
Call start/end events, durations, call outcomes, agent assignment.
Deep link / click-to-call support
Embed 'Call us on WhatsApp' links/buttons on web/app.
Switch context between chat and voice
Escalate a chat to voice call when needed, no new tool/context.
CRM / agent routing integrations
Route calls based on chat metadata, tags, integrate with your CRM or backend.
Compliance & security
Since voice runs inside WhatsApp Business Platform, you benefit from Meta's encryption/security; you maintain logs.
Global reach
Works internationally (within supported countries) – one code base, one number, global users.
Simple enablement
You've built the toggle-on model, making it quick for developers/customers to turn on voice.
Note: Video calling support is not yet available. We're continuously working on expanding our capabilities based on Meta's roadmap.
Transforming Industries with Voice
See how businesses are leveraging WhatsApp Calling to enhance their operations.
Customer Support
Escalate complex support tickets to a voice call for quicker resolution. Perfect for tech support and service industries.
Simple, Transparent Pricing
No setup fees. No hidden charges. Only pay for what you use.
Incoming Calls
FREE
Receive calls from your customers at no cost
Outgoing Calls
Billed per minute based on the recipient's country
Rates are set by Meta, and we don't add any markups
Business-initiated calls are charged based on:
Duration of the call
Calculated in six-second pulses
Country code
Of the phone number being called
Volume tier
Based on minutes called within the calendar month
Note: Our systems count fractional pulses as one pulse. For example, a 56-second call (9.33 pulses) would be counted as 10 pulses.
Volume-Based Pricing (VBP) Rate Cards
These rate cards represent the current VBP rates for WhatsApp Business Calling API effective August 1, 2025:
Get started in minutes with the WhatsApp Business Calling API
Three simple steps to enable voice for your WhatsApp API number.
Sign up or log in to SendZen.io
Complete WhatsApp embedded signup and connect your WhatsApp Business API number (if you haven't already).
Enable voice calling in your dashboard
Toggle the "Enable WhatsApp Voice Call" switch, set permissions (inbound/outbound) and embed the "Call us" button/link on your website/app.
Use our voice API endpoints
Start using our API to initiate calls, listen for call webhooks, integrate with your CRM/automation.
POST /voice/call
{
"to": "+1234567890",
"from": "your_whatsapp_number"
}Why choose SendZen.io for your WhatsApp Business Calling API?
The developer-first WhatsApp voice API you've been waiting for.
Built exclusively for WhatsApp
Unlike some providers who offer many channels but dilute focus, we specialise in WhatsApp (chat + voice) so your WhatsApp use-case is first-class.
Developer-friendly setup & API
Self-serve signup, SDKs, dashboards, webhooks — you control everything without heavy onboarding.
Instant enablement
As you've already built the embedded signup+toggle feature, customers can go from zero to voice calls in minutes.
Unified messaging + voice flows
You keep the same number, same profile, same thread; no tool sprawl.
Transparent pricing
No hidden mark-ups, no surprise fees; we pass through WhatsApp/Meta rates (or clearly state our platform fee).
Scalable architecture & enterprise-ready
Designed for high volume, multi-user/reseller setups, compliance (GDPR/CCPA/SOC2) — because you told us you prioritise this.
Support & ecosystem
You integrate easily with SDKs, automation tools, CRM, stronger developer-ecosystem than general BSPs.
Frequently Asked Questions
Everything you need to know about WhatsApp Business Calling API with SendZen.
Ready to Ship Faster?
Create an account and enable WhatsApp Calling in minutes. No credit card required.
"We're not just building a product, we're solving a pain we've felt firsthand. We're building the API that developers deserve, one that is simple, reliable, and a joy to use."
— Milan Motavar, Founder & CEO, SendZen