SMS API built for speed and scale

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Everything you need from an SMS API

Lightning quick

SMS is the fastest way to reach any mobile phone. Use our API for delivery in seconds and a setup process that sees your first message sent on the same day.

Reliable performance

Rest assured that time-sensitive text messages will be delivered securely and on-time, with industry leading performance and built-in compliance, including GDPR and ISO 27001.

Effortless integration

With our quickstart guides and 24/7 professional support, set up and integration into your existing systems is straightforward for developers and no-code teams alike.

> 5bn messages

Each year over five billion messages are delivered through our messaging API by businesses worldwide.

99.9% uptime

Scale your messaging without experiencing dips in performance. Rely on 99.9% uptime for reliability during peak times.

< 2 hours

Most teams send their first live message in under two hours with our straightforward set up, integration and expert support.

// 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": {}
}

Not a coder? We’ve got you covered

“Our estate agent customers need to send appointment reminders and property transaction updates reliably and on time. With SMS from Esendex, texts land straight into the hands of the agent’s clients when they are most valuable to them.”

Let’s start sending, together.

Why choose Esendex?

20+ years of experience
Industry leading support
An expert and reliable partner
One-on-one with everyone
Flexible and scalable options
Solutions designed for you

Get the most out of SMS with our powerful API

Notifications and alerts

Send instant updates on orders, deliveries, and service changes to keep customers informed.

Two-factor authentication (2FA)

Protect user accounts with secure one-time passcodes sent quickly by SMS.

Marketing campaigns

Deliver personalised promotions and offers directly to your customers’ phones.

Appointment reminders

Reduce missed appointments with clear and timely SMS reminders.

Automate messages

Set up intelligent workflows to automate responses and manage customer journeys by SMS.

Surveys and feedback

Collect valuable insights with quick customer surveys sent by SMS.

FAQs

How do I know if my message has been delivered?

Our API provides real-time delivery receipts so you can track the status of every message you send.

Is the SMS API secure and GDPR compliant?

Yes. Our platform is fully compliant with GDPR and ISO 27001, with encryption in transit and at rest.

What kind of support is available during and after integration?

You’ll have access to 24/7 support from our expert team, plus free setup assistance if you need it.

Can I send messages internationally using the API?

Yes. Our SMS API supports global delivery to over 190 countries with the same reliability and speed.

What programming languages are supported?

We provide clear examples in JavaScript, Python, Java, C#, PHP and cURL in our support docs to help you integrate quickly.

Is there a sandbox or testing environment available?

Yes. You can test and simulate messages safely using our dedicated sandbox environment.

Do I need coding skills to use the API?

No. While developers can integrate directly, no-code teams can use our tools and guided setup.

Are there templates or pre-configured integrations available?

Yes. Our API works with platforms like Salesforce and Zapier, alongside pre-built message templates.

Let’s start sending, together.