MESSAGING API
Scalable SMS API from the messaging experts
Our secure SMS API allows you to programme your text message sends in a way that’s scalable for your business. It’s never been easier to reach your customers and communicate within your organisation.
One API for SMS, WhatsApp and RCS messages
Reliable, scalable and flexible APIs brought to you by the messaging experts.
At Esendex, we have more than 20 years of experience understanding complex business challenges and helping organisations find innovative ways to integrate messaging into their existing software – including SMS (and MMS), WhatsApp and RCS.
From delivery notifications and appointment reminders to marketing alerts, we can boost the speed, quality and delivery of your services by helping you automate your messaging with our SMS API.
One connection for a world of seamless communication.
One-way and two-way conversations
Like any API (application programming interface), an SMS API links two applications – in this case your software and an SMS gateway – using a HTTP request. Thanks to the scalable structure of our SMS API, you can seamlessly manage, automate, schedule, and optimise message volumes as you require, while ensuring messages are correctly formatted for various telecoms networks.
What is an SMS API?
Our SMS API allows organisations to send out timely one-way messages – including special offers and deals, and appointment or reservation reminders. You can also set up two-way conversations, via our SMS Chat – helping to resolve enquiries and boost engagement far quicker and more cost effectively compared to phone calls.
How does it work with SMS gateway?
An SMS gateway is the infrastructure that enables the sending and receiving of messages between networks and applications. Once instructions have been received via the API, the gateway converts messages from the programme code used to a format that is compatible with the mobile network, and then pushes them out to users.
How do you integrate an SMS API?
Esendex’s APIs are developed for ease of use, and can be integrated within minutes. We’ve put together a series of quickstart guides to show you how.
What programming languages can I use?
Esendex SMS API supports multiple languages, including Python, Java, C#, cURL, PHP and Node JS. Find out more in our developers’ section.
Why choose Esendex for bulk SMS?
Fast, reliable message delivery
Our direct connections to all major networks ensures secure message delivery to both local and international customers, via the fastest and highest quality routes available.
Multichannel, global, scalable messaging
Send messages automatically to any country in seconds. Choose from SMS, WhatsApp or RCS messaging options, from a provider that sends billions of messages per year.
Robust, dependable connectivity
Be confident that your time critical messages will always be sent. Our APIs and messaging platform consistently achieve an uptime of 99.99% availability.
Easy, quick integration
Be ready to send and receive messages in minutes. Our swagger formatted developers’ documentation will help guide you through how to implement our SMS messaging APIs seamlessly into your website or application.
Local support with a global reach
Access all the benefits of a global provider with the personal touch of expert local support. With access to a dedicated account manager, you can get support whenever you need it.
End-to-end data and security protection
Our ISO 27001 accreditation and usage of the most secure communication protocols (TLS 1.2) shows our commitment to protecting our customers’ data. We do not use grey routes. Our APIs are served using HTTPs to ensure data privacy.
Let’s start sending, together.
Discover the full power of our mobile messaging platform.
Key features of our SMS API
Send personalised and customised messages to single or multiple contacts.
Retrieve inbound messages.
Create and save SMS templates with dynamic fields that can be personalised to each recipient.
Be confident your messages have arrived by easily seeing the status of your messages and their send/delivery success.
For WhatsApp and RCS messages, you can also review click and read rates.
In addition to tracking message delivery status and engagement metrics, you can add metadata to sent messages (e.g. campaign code or details specific to each recipient).
This means you can segment data, making it easier to report on responses from different types of customers.
Quickly and easily retrieve the number of message credits you have remaining for each of your accounts and channels.
With our API, you can view balance information all in one place.
Built by developers, for developers. Integrate our APIs for simple, real-time communication
Use our API documentation to integrate Esendex’ services into your systems within minutes. Here’s how to send an SMS:
// The POST v1/messages endpoint allows you to send a message to a single contact in one request.
// The message can also be sent via different channels; including SMS, Whatsapp and RCS.
curl -X POST 'https://api.esendex.co.uk/v2/messages' -H 'X-Api-Key: {{your-key-here}}' -H 'Content-Type: application/json' -d
{
"accountReference": "EXxxxxxxxx",
"name": "name",
"characterSet": "characterSet",
"channel": "channel",
"from": "from",
"validity": "2025-07-30T09:38:04.4517739+00:00",
"messageType": "messageType",
"body": {
"text": "text",
"templateId": "templateId"
},
"recipients": [
{
"msisdn": "msisdn",
"variables": {},
"metaData": {}
}
],
"addressBook": {
"contacts": [
{
"id": "id"
}
]
},
"metaData": {}
}No commitment, 30 day free trial
Begin your journey by opening a free Esendex account today and get 100 SMS credits.
Ready? Set? Go!
Learn how to get your service up and running with our simple quickstart guides.
We help build experiences, not just software
Our messaging API makes it easy for you to forge stronger connections with your customers, using a single platform. One API is all you need. Here’s how we’ve helped other businesses…
Spotler improves customer engagement when they add SMS via Esendex
B2B marketing automation software provider Spotler wanted to add SMS as an additional comms channel to their platform. A partnership with Esendex has given Spotler the chance to send SMS alongside their existing email strategy to end customers, improving engagement and experience.
Capgemini deploys a robust click-and-collection solution, thanks to Esendex’s SMS API
Approached by a major high street retailer to launch their new click-and-collect service, Capgemini chose our SMS API to help. Since implementing this automation, their end customer’s ecommerce division has increased.
