Messaging API
Up your open rate with our email API
Our powerful email API quickly connects to your business systems, making it easy to deliver engaging, cost-effective and compliant email communications.
Designed for developers and no-code teams, our industry-leading email API can be up and running within hours and offers in-built security and scalability.
High-performing and fully-supported, the Esendex email API is build-once, so users benefit from regular updates and new features that improve usability and results.
Everything you need from an email API
Seamless integration
Integrate our email API with your existing software and be up and running in hours not days. Suitable for both developers and no-code teams, take advantage of our quickstart guides and 24/7 professional support to get started.
Secure and experienced
Esendex is ISO 27001 accredited – helping you protect customers’ data and comply with GDPR. We work with 46,000 customers and have 25 years’ experience in the business messaging industry.
Easy to use
From drag-and-drop templates, to segmentation tools and in-built validation, teams can set up and monitor campaigns that get results.
>5bn messages
Each year over five billion messages are safely 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.
Built by developers, for developers. Integrate our email API for simple, real-time communication
Use our API documentation to integrate Esendex’ services into your systems within minutes. Here’s how to send an email:
// 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.
Not a coder? We’ve got you covered
Our managed services team can help you set up and run your email API at no extra cost. From initial configuration to testing and live deployment, we’ll make sure everything is in place so you can start sending messages with confidence.
“We’ve seen a big uptick in our arrangement and collection numbers, but more importantly, we’re also providing better services and tools to our customers.”
Gareth Hall – Senior Collections Manager, Debt Managers
Let’s start sending, together.
Discover the full power of our mobile messaging platform.
Why choose Esendex?
Having us in your corner ensures that you can support your customers and your business – whatever comes your way.
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 email with our powerful API
Drag and drop template editor
Create and edit emails with our drag and drop template builder, whether you’re low code or no-code. Use our template for inspiration – or tailor to your brand.
One to many personalisation
Send personalised emails at scale – scheduling and tailoring them to your customers’ preferences based on their previous interactions with you.
In-built email validation tools & reporting
An in-built validation tool classes every email address – alerting you to those that might fail to deliver. Advanced reporting and analytics help you track the results and measure ROI.
Make segmentation simple
Apply single or multiple filters, choose from pre-built categories or create your own for easy segmentation. With pre-built behavioural filters, you can re-engage based on previous interactions and use our form builder to offer easy opt-ins.
Multichannel
Enhance your email communications with SMS, RCS and WhatsApp through our multichannel API.
Preview and test
Quickly preview emails to ensure they render on mobile, desktop and across all major email clients. Our A/B testing tool checks up to 10 variants at a time, so you can hone your offers and design to send the best email, every time.
FAQs
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How do I know if my message has been delivered?
How do I know if my message has been delivered?You can check the status of every message with real-time delivery receipts – which comes as standard with our API.
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Is the email API secure and GDPR compliant?
Esendex is ISO 27001 accredited and supports compliance with GDPR – so data is protected to the highest standards. This helps you to maintain trust and improve engagement with your customers.
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What programming languages are supported?
JavaScript, Python, Java, C#, PHP and cURL are all supported, enabling fast integration.
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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.
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Is there a sandbox or testing environment available?
Yes. You can test and simulate messages safely using our dedicated sandbox environment.
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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.
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Are there templates or pre-configured integrations available?
Yes. Our API works with platforms like Salesforce and Zapier, alongside pre-built message templates.
