Business Messaging API for SMS, WhatsApp, Viber & RCS

Stop juggling multiple APIs. Integrate one unified messaging API from BulkGate to send and manage business messages across SMS, WhatsApp, Viber, and RCS — all from a single platform.

Get started with Messaging API View API documentation

18,078 companies worldwide trust BulkGate

Why choose BulkGate as your Business Messaging API provider?

One API for all channels

Save development time with a single integration that handles SMS, WhatsApp, Viber, and RCS with consistent parameters and workflows.

Intelligent routing and reach

Improve delivery with smart channel selection and configurable fallback sequences, such as WhatsApp → Viber → SMS.

Learn more about multichannel communication

Everything under control from one place

Manage campaigns, track performance, and compare metrics and spending across all channels — all from one dashboard or via the API.

Advanced message capabilities

Use customer data for advanced personalization and define content for each channel in a single API call.

Supported channels for our unified Messaging API

Access a wide range of popular communication channels through our unified API. Choose the right channel for each use case and customer preference, all with seamless management.

SMS

Viber

RCS

Voice

SMS API

Reach mobile users worldwide without internet. Use SMS for OTPs, notifications, and promotions.

Explore SMS API

POST /api/2.0/advanced/transactional HTTP/1.1 Host: portal.bulkgate.com Content-Type: application/json Cache-Control: no-cache { "application_id": 451, "application_token": "YDbkJ5tXeZkqF48dCQEHiVMiK1m95atbhbn83CYHi0BareuraP", "number": "777777777", "channel": { "whatsapp": { "sender": "420777777777", "expiration": 300, "template": { "template": "pick_up_template", "language": "en", "header": { "type": "image", "url": "https://example.com/image.jpg", "caption": "Your car is ready for pick up!" }, "body": [ { "type": "currency", "amount": 20.5, "currency": "EUR" } ], "buttons": [ { "type": "payload", "index": 1, "payload": "take_me_to_the_car" } ] } } } }

WhatsApp Business API

Reach over 2 billion users with media, interactive templates, and a verified business profile.

Explore WhatsApp API

POST /api/2.0/advanced/transactional HTTP/1.1 Host: portal.bulkgate.com Content-Type: application/json Cache-Control: no-cache { "application_id": 451, "application_token": "YDbkJ5tXeZkqF48dCQEHiVMiK1m95atbhbn83CYHi0BareuraP", "number": "777777777", "variables": { "first_name": "Johny", "last_name": "Silverh@nd" }, "country": "gb", "schedule": "2023-08-21T23:30:52+02:00", "channel": { "viber": { "text": "Your car is ready for pickup, {{first_name}} {{last_name}}. Please visit our service center.", "sender": "MyCompany", "expiration": 120, "use_template": false, "template_id": null, "template_language": "en", "template_parameters": [] } } }

Viber Business API

Send images, buttons, and interactive messages to 1.3 billion users within 24-hour conversations.

Explore Viber API

POST /api/2.0/advanced/transactional HTTP/1.1 Host: portal.bulkgate.com Content-Type: application/json Cache-Control: no-cache { "application_id": 451, "application_token": "YDbkJ5tXeZkqF48dCQEHiVMiK1m95atbhbn83CYHi0BareuraP", "number": "777777777", "country": "gb", "text": "Your order #1234 is ready for pickup. Please visit our service center.", "channel": { "rcs": { "sender": "BulkGate", "expiration": 300, "card": { "title": "Your order is ready!", "description": "Order #1234 is waiting for you at our service center.", "alignment": "left", "orientation": "vertical", "media": { "url": "https://example.com/order.jpg", "height": "Medium" }, "suggestions": [ { "type": "open_url", "text": "Track order", "url": "https://example.com/track/1234" }, { "type": "dial_number", "text": "Call us", "phone_number": "+420777777777" } ] } } } }

RCS Business API

Send branded messages with carousels, buttons, and media to 2.5+ billion users directly in their default messaging app.

Explore RCS API

curl -X POST https://portal.bulkgate.com/api/2.0/advanced/transactional \ -H "Content-Type: application/json" \ -d '{ "application_id": "12345", "application_token": "your_api_token", "number": "420777123456", "channel": { "voice": { "text": "Váš kód je 4 5 6 7", "language": "cs", "voice": "female", "repeat": 2 } } }'

Voice API

Capture immediate attention with critical alerts, voice OTPs, or personalized automated calls.

View Voice API pricing

Robust API security and full budget control

Compromised API keys and automated attacks can cause unauthorized messaging and unexpected costs. Security features and budget limits help reduce the risk.

Intelligent protection and traffic monitoring

Minimize risks and stay informed with proactive security features and automatic alerts across all your messaging traffic.

Duplicate message prevention

Prevent repeated sending of identical messages to the same recipient on any channel within a short time frame.

Contact flood prevention

Set rules limiting message frequency to a single contact across channels within a specified period.

Trend monitoring and alerts

We monitor sending patterns across all your channels and automatically notify you by email when significant deviations occur.

Flexible API token and access management

Optimize security and visibility when working on multiple projects or with external partners through granular access management.

Multiple API token management

Create and manage unique API tokens for different applications, projects, or teams using any of the messaging channels.

Separate financial coverage

Link API tokens to different wallets for detailed cost control and protection of your main account balance.

Token validity management

Easily invalidate or temporarily deactivate existing API tokens at any time.

Advanced budget and API limit management

Keep your multi-channel messaging costs under control and prevent any misuse that could lead to budget overruns.

Sending limits and destination control

Set daily limits globally or by country, and block destinations to prevent unauthorized sending across channels.

API request throttling

Set maximum API calls per second/minute to protect your system against overloading.

Automated actions when limits are exceeded

Choose what happens to messages after reaching your configured caps (e.g. queue, reject).

Flexible integration options

Implement our Business Messaging API effortlessly into your workflows.

Clean REST API

Connect using standard HTTPS with structured JSON request/response formats

Use comprehensive documentation with ready-to-use examples

Rely on a scalable platform built for high performance

Learn more

Helpful SDKs

Speed up development with our official PHP SDK or connect via HTTP API from any programming language

Our SDKs simplify common tasks like authentication and cross-channel messaging

Actively maintained and updated to support new features and channels

Learn more

Transparent Business Messaging API pricing

With BulkGate's Business Messaging API, your costs are primarily based on the messages you send through each channel — there are no additional fees for using the unified API itself.

SMS

Price per message from €0.0301

RCS

Price per message from Price on demand

Price per message from €0.004

Viber

Price per message from €0.007

Voice

Price per message from Price on demand

Prices are for domestic traffic. International rates may vary. Volume discounts are available.

View full pricing

Get started with Business Messaging API in 3 simple steps

Start for free now

Create a free BulkGate account and activate the communication channels (SMS, WhatsApp, Viber, RCS) you want to use.

Get your API key and integrate

Generate your universal API key and start integrating into your systems using our documentation and SDKs.

Send messages across all channels

Once your channels are approved and activated, you can start sending messages through all of them at once.

Developer support and resources

We're committed to ensuring your integration succeeds. Access rich resources and help when you need it.

Comprehensive API documentation with guides and tutorials

Ready-to-use SDKs and extensive code examples

Reliable technical support via email

Frequently asked questions

What is BulkGate's Business Messaging API?

It's a unified programming interface that enables your applications to send and receive messages across multiple channels (SMS, WhatsApp, Viber, RCS) through a single integration. This simplifies development, standardizes your code, and enables intelligent channel routing.

Which communication channels are supported?

Our unified API currently supports SMS, WhatsApp Business Platform, Viber for Business, and RCS Business Messaging. You can use all channels or only those that fit your business needs.

How does channel selection and fallback work?

You can configure channel selection in three ways: 1) Specify a single preferred channel, 2) Set priorities for cascading delivery attempts across multiple channels, or 3) Let our system automatically optimize based on cost, features, or historical engagement data.

Do I need to format messages differently for each channel?

No. One of the key benefits of our unified API is that you can send a standardized message format and our system automatically adapts the content to each channel's requirements and capabilities. If you prefer, you can also provide channel-specific formatting.

How do webhooks work for multi-channel messaging?

We provide unified webhooks that standardize events across channels. When a message status changes or a reply is received, you get a consistent webhook format regardless of the original channel, simplifying your integration.

How does pricing work for the unified API?

Pricing varies by channel. For SMS, you pay per message sent. For WhatsApp, Meta charges per 24-hour conversation (based on category and country), and BulkGate adds a per-message fee. For Viber and RCS, pricing is per delivered message and may vary by message type (e.g. text vs. rich media). There's no extra fee for using the unified API itself — you're charged according to each channel's specific rate and model. Volume discounts are available for SMS and Viber. See our detailed pricing page for each channel.

Do I need a separate sender identity for each channel?

Each communication channel has its own sender identification. For SMS, you can use a text sender ID, short code, or phone number. For WhatsApp, it's your verified WhatsApp Business Account (WABA) and associated phone number. Viber uses a verified business profile. Our platform helps you manage these different sender identities, and you specify the appropriate one when sending messages via the API for each channel.

Can I track analytics across all channels?

Yes, our platform provides unified analytics that let you compare performance across channels. You can track delivery rates, engagement, conversion metrics, and cost effectiveness to optimize your business communication strategy.

Is BulkGate's Business Messaging API GDPR compliant?

Yes, our entire communication infrastructure fully complies with GDPR. We provide tools for consent management, data access requests, and data deletion across all communication channels to help your business meet its compliance obligations.

Can I migrate gradually from a single-channel to a multi-channel API?

Yes. You can continue using your existing single-channel integrations and gradually adopt the unified API. We provide migration guides and support to help you transition at your own pace without disrupting existing services.

Ready to simplify your business communication with a single API?

One API, all channels, no compromises. Join 18,078 businesses that have streamlined their business messaging with BulkGate.

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