Multichannel API

Unify your communications with our multichannel API

Our multichannel API allows you to manage SMS and RCS (WhatsApp coming soon) all in one place, so you can choose the most appropriate channel based on channel engagement and your unique customer journey.

Seamlessly connect our scalable multichannel API with your business systems to unlock new messaging opportunities and unified analytics that drive cross-channel improvements. The Esendex Multichannel API is a single integration that lets you send SMS and RCS messages from one connection, switching channel with a single parameter change instead of building a separate integration for each.

RCS is not yet supported in Australia. Contact us today to be one of the first to know when RCS is available.

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What is a multichannel API?

A multichannel API – sometimes known as CPaaS, or communications platform as a service – is a single integration that lets a business send messages across multiple channels (such as SMS, RCS, WhatsApp, Email, and Voice) through one connection, rather than integrating with each channel separately. Esendex’s multichannel API brings these channels together under one connection, with local, human support, enabling you to scale your communication strategy.

Scalability made simple with multichannel APIs

Multichannel APIs are more than just messaging tools. They’re enablers for ROI, customer retention, and operational efficiency, and with Esendex, they’re brilliantly simple.

Meet your customers where they are

Seamlessly switch from universal-reach SMS to rich media RCS messaging, choosing the right channel for the right interaction to boost your customer engagement.

Reduce API sprawl and complexity

Reduce development time, consolidate API sprawl, and decrease time-to-value with our modern multichannel REST API architecture: one format, one base URL, and one API key.

Optimise messaging performance

Centralise reporting and gain insights into the performance of your multichannel messaging. Analyse cross-channel open, click, and engagement rates to optimise your outreach.

Why choose Esendex as your multichannel API provider?

Built for outcomes

Our multichannel REST API future-proofs your operations and eliminates API complexity with its modern architecture: one format, one base URL, and one API key.

Multichannel agility

Unlock multichannel scalability and unify channel orchestration by transitioning from SMS to RCS with one simple parameter change.

Fast integration

Reduce time-to-value and skip complex setup. Our modern architecture means you can set up your API in as little as 3 hours1, with dedicated local support included as standard.

Enterprise-grade security

Rest easy with a ISO 27001 and Cyber Essentials certified supplier, supported by proactive 24/7 vulnerability scanning built to strict OWASP guidelines

Local, human support included

Direct access to AU-based support, with over 20+ years experience – bypassing premium paywalls and expensive support-tier subscriptions.

Universal, global reach

Send messages worldwide with confidence. Our direct carrier connections and in-country knowledge ensure reliable delivery across borders.

Built by developers, coded for simplicity.

Our multichannel REST API and intuitive developer documentation enable teams to go from zero to sending in under 3 hours1. Skip the complex setup and benefit from simple modern architecture with world-class documentation and free, local, human support.

API documents

World-class documentation and copy-pasteable code samples that are designed for multichannel immediate deployment.

Developer Documents

Not a developer?

Our brilliantly simple, intuitive developer documents are easy to read and understand, even without a technical background.

Developer Documents

What channels are available with our multichannel REST API?

Simply change a single JSON parameter to switch between SMS and RCS messaging.

RCS Business Messaging

Replace standard text-only messages with the functionality of a dedicated mobile app with high-res media, branding, and interactive buttons, delivered to native messaging apps across both iOS and Android, with no extra app download required.

Popular use cases include:

  • Marketing promotions
  • Security and 2FA messages
  • Inbound customer support
  • Booking and appointment reminders
Learn more
A smartphone mockup displaying a Rich Communication Services (RCS) message featuring brand verification, rich media, and interactive buttons.
A smartphone mockup displaying a standard text-based SMS notification.

SMS

Reach customers in seconds with text message alerts, reminders, and marketing campaigns, with universal global reach.

Popular use cases include:

  • OTPs and verification codes
  • Delivery updates and reminders
  • Welcome messages
  • Broadcast business updates
Learn more

WhatsApp Business Platform (Coming soon)

Add WhatsApp Business Platform to your customer communication strategy and reach your customers on the world’s most popular messaging app, with 2-way encrypted messaging and rich media capabilities.

Popular use cases include:

  • Marketing promotions
  • Alerts and updates
  • Inbound customer support
  • Booking and appointment reminders

The importance of SMS fallback

SMS Fallback is crucial to the success of any CPaaS API, as so many channels rely on a stable internet connection to deliver messages.

A side-by-side smartphone comparison showing a rich media RCS message with branding and interactive buttons next to its standard text SMS fallback alternative.

If a message isn’t delivered to a recipient through RCS or WhatsApp (Coming soon), the Esendex multichannel REST API automatically re-routes the message via SMS fallback, ensuring near-universal reach.

What is SMS fallback?

SMS fallback is the process of messages being sent via SMS when a rich-media message send fails due to a recipient’s internet connection. SMS fallback can be turned on easily through the Esendex multichannel REST API.

How does it work?

1 – Instant failure detection: If a rich-media message cannot be delivered due to device or network compatibility, our multichannel REST API catches the non-delivery status instantly.

2 – Automated SMS fallback: The API automatically re-routes the messages as an SMS, guaranteeing delivery without manual intervention.

The power of our platform, without leaving yours

Multichannel Flexibility

Use your customers’ preferred channels and reduce friction as you move between them, because every channel runs through the same API and account.

Cross-channel reporting

By bringing all your communications channels together with centralised reporting, you can quickly identify areas for improvement using advanced dashboards and analytics.

Brand alignment

Deliver a consistent brand experience for customers as they move across channels, with SMS and RCS deployed from a single integration.

Brilliantly simple integration options

Integrate with your bespoke or industry-leading systems through the same modern REST architecture, used by 90% of modern web apps.

Automate routine interactions

Automate repetitive and time-consuming tasks associated with repeat queries or low-value conversations that are distracting customer support resources.

Template management and scheduling

Quickly create, preview, and schedule templated messages through the API, ensuring you’re 100% satisfied with the message your customers will receive before it hits their phones.

Trust, compliance and reliability

Every message sent through the Esendex Multichannel API carries verified sender identity appropriate to the channel – from RCS verified business profiles to dedicated SMS short codes and sender IDs – so customers can see who they’re really talking to. Messaging is handled under the same GDPR-aligned processes and ISO 27001-certified infrastructure as the rest of the Esendex product suite, and when a device, network, or customer can’t receive a richer channel like RCS or WhatsApp, messages fall back automatically to SMS rather than failing to deliver, giving near-universal reach on a global scale.

“Operationally, WhatsApp offers significant engagement opportunities – from outbound notifications, reminders and status updates to marketing and promotions. The combination of chatbot automation and WhatsApp has also had a direct impact on our bottom line”

Lucie Riley – Chief Operating Officer, Rhenus Home Delivery

Rhenus case study

How fast can you send your first SMS?

Sign up for your free trial, grab your API key, and dispatch your first SMS via our REST API in under 5 minutes flat2.

Sign up for your free trial

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Watch our attempt

Watch our engineer complete it in under 3 minutes.

Multichannel API FAQs

What is a multichannel (or omnichannel) messaging API?

A multichannel API is a single integration that lets a business send messages across more than one channel – such as SMS, RCS, WhatsApp, voice and email – from one connection, rather than building and maintaining a separate integration for each channel. It’s sometimes called an omnichannel API, or referred to more broadly as CPaaS (communications platform as a service).

What is CPaaS?

CPaaS stands for communications platform as a service. It’s a category of tools, including multichannel messaging APIs like Esendex’s, that let businesses add messaging, voice and other communication features to their own systems through a single API rather than building the infrastructure themselves.

What happens if a channel like WhatsApp or RCS isn’t available for a recipient?

If a message can’t be delivered on the preferred channel – for example because a recipient’s device or network doesn’t support RCS – the Esendex Multichannel API can automatically re-route the message to SMS, so it still reaches the recipient rather than failing to send.

How is this different from using separate SMS, WhatsApp and RCS APIs?

Using Esendex’s multichannel API means one integration, one contract and one support team cover every channel, instead of managing a separate API, billing relationship and set of credentials for each channel individually.

Do I need coding skills to use the multichannel REST API?

No. Our intuitive developer docs are designed for simple self-serve usage. If you don’t have the resources to integrate our API yourself, reach out to our support team, who will be happy to assist.

1 From Account setup and verification to first successful API SMS send. Based on the average time taken for a new REST API Prepay customer (03/25 – 05/26)

2 Based on our fastest customer integration time from free trial sign-up to first successful SMS message sent via API and independent in-house testing.

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