BUILT FOR DEVELOPERS, CODED FOR SIMPLICITY
Intuitive
SMS API
built to scale
Integrate two-way SMS, transactional alerts, and automated broadcasts into your tech stack in under 3 hours1 with our SMS API options, built for developers and no-code teams alike.
Built for high-volume and coded for simplicity, deploy SMS messages in minutes with our sms sending APIs, intuitive developer documents, and local, human support
How can I use an SMS API to send messages?
Our business SMS API options integrate the Esendex platform directly into your service platform or another software in your tech stack. This enables you to send, receive, and automate text messages seamlessly, decreasing deployment time and increasing operational efficiency.
With the Esendex API Product Suite, you have two brilliantly simple integration options – our multichannel REST API and our robust SMPP Protocol for high-throughput SMS volume.
Two brilliantly simple integrations
because sending SMS shouldn’t be complex
Unlock multichannel capabilities through our REST API
The Esendex multichannel REST API allows teams to dispatch universal reach SMS messages, but also automate rich media RCS messages, over secure HTTPS.
Instead of dealing with API sprawl across siloed platforms, our REST API delivers rapid connectivity that enables simple, multichannel integration.
Key benefits of our multichannel REST API:
- Unify channel orchestration: Transition seamlessly between SMS and RCS with one parameter change.
- Reduce time-to-value: Go from setup to live sending within 3 hours1.
- Remove developer friction: Built with one JSON format, one base URL, and one API key.
Achieve high-volume SMS throughput with our SMPP Protocol
Our robust SMPP Protocol is the foundation for heavy-duty, mission-critical SMS outreach, allowing teams to control messaging traffic, stream high-volume sends over direct connections, and receive real-time insights without performance bottlenecks.
Perfect for high-volume, repetitive messaging such as system updates, promotional broadcasts, and internal operational alerts.
Key benefits of our SMPP Protocol:
- High-throughput streaming: Reach thousands of recipients in one send with ultra-low latency.
- Uninterrupted connectivity: Send messages without interruption with SMPP’s BIND architecture
- Enhanced security and reliability: Secured via mandatory TLS 1.2+ or VPNs.
Built by developers, coded for simplicity.
Use our intuitive developer documentation to integrate our API Product Suite with your existing systems in as little as 3-hours1.
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API documents
API documentsWorld-class documentation and copy-pasteable code samples that are designed for multichannel, immediate deployment.
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Not a developer?
Not a developer?Our brilliantly simple, intuitive developer documents are easy to read and understand, even without a technical background.
Why Developers choose Esendex’s API Product Suite
Unlike many SMS API service providers, Esendex brings over 20 years of business messaging experience and includes 24/7 support as standard rather than as a paid add-on.
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 an ISO 27001, ISO 27018 and Cyber Essentials certified supplier, supported by proactive 24/7 vulnerability scanning built to strict OWASP guidelines
Local, human support included
Direct access to UK-based technical engineers, 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.
What will you send first through our SMS API?
Here are some of the most popular use cases on the World’s most popular messaging channel.
Marketing promotions
Tell your customers about upcoming offers and promotions.
Delivery updates and reminders
Send automated reminders to inform customers about appointment and delivery updates.
OTPs and verification messages
Send OTPs and MFA messages directly to your customer’s device to confirm their identity.
Employee comms
Provide company-wide internal updates with high-SMS throughput.
Scale your communication with these core SMS features
MASS TEXTING
Bulk SMS
Reach your customers instantly with time-sensitive updates and offers that are guaranteed to be seen and acted upon, driving service standards, immediate traffic and revenue.
CUSTOMER SERVICE
SMS chat
Provide an easy way for your customers to effortlessly connect with you, without having to download an app or create a login. They simply use the SMS app that is on all mobile phones.
STREAMLINE TOOLS
Email to SMS
Supercharge your email! Esendex Email-to-SMS enables you to send SMS from the comfort of your existing email. Enjoy the convenience of using the email platform you are used to, without the need to log into any additional software.
IMPROVE EXPERIENCE
SMS Surveys
Improve customer experience and get instant feedback from customers or staff, using engaging 2-way SMS surveys.
SMART AND SIMPLE
SMS Short Codes
Build brand recognition and boost response rates by using memorable five-digit numbers for promotions, surveys, or customer replies. Ideal for high-volume two-way messaging and brand recall.
INTEGRATE SMS
SMS Gateway
Experience peace of mind with enterprise-grade reliability and high-speed routing that ensures your alerts, codes, and notifications reach their destination on time, every time.
PERSONALISE SMS
SMS Sender ID
A business SMS Sender ID creates a professional impression while instantly notifying the end-user of your identity. Whether you choose your brand name, a customer representative’s name or a unique campaign, a customised ID boosts brand familiarity and engagement.
How fast can you send your first SMS API message?
Take on our 5-minute challenge
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
Watch our attempt
Watch our engineer complete it in under 2 minutes and 20 seconds.
Trusted by UK businesses like Houseful to deliver time-critical property and appointment messaging at scale.
“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.”
Riccardo Dawson – Chief Operating Officer, Software at Houseful
Trust, compliance and reliability
Every SMS sent through the Esendex API Product Suite goes out from a dedicated short code, virtual mobile number, or verified sender ID, so recipients can see exactly who’s messaging them. Messaging is handled under the same GDPR-aligned processes and ISO 27001and ISO 27018-certified infrastructure as the rest of the Esendex product suite, and because SMS works on any mobile phone without needing an app, data connection, or smartphone, delivery isn’t limited by device or network support the way richer channels can be. Combined with Esendex’s direct connections to mobile network operators across 190+ countries and adaptive routing that keeps delivery rates high, that gives you near-universal reach on a global scale.
SMS API FAQs
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What is an SMS API?
What is an SMS API?An SMS API is a set of tools that lets software send and receive text messages automatically, without manual sending. Businesses use it to trigger messages like order updates, appointment reminders, or one-time passcodes directly from their own systems.
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How much does the Esendex SMS API cost?
Pricing depends on message volume and destination. You can view current UK plans on our pricing page, or start with a 7-day free trial with no commitment.
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Can I integrate the SMS API with Salesforce or Zapier?
Yes. The Esendex API works with platforms including Salesforce and Zapier, alongside pre-built message templates, so you can connect SMS to your existing workflows without custom development.
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Can I send SMS internationally with the Esendex API?
Yes. The Esendex SMS API sends to over 190 countries, with local routing and compliance handled for you, so you can message customers wherever they are.
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What phone number types does the Esendex SMS API support?
You can send from a dedicated short code, a virtual mobile number, or your own verified sender ID, with adaptive routing to keep delivery rates high across UK and international networks.
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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Everything you need from an SMS API
Lightning quick
SMS is one of the fastest ways 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, setting up and integrating 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.
A reliable API
Scale your messaging without experiencing dips in performance for reliability during peak times.
Quick setup
Send your first live message quickly with our straightforward set up, integration and expert support.
Built by developers, for developers.
Integrate our APIs for simple, real-time communication
Use our API documentation to integrate across your services and systems in no time.
No commitment, 7 day free trial
Not a coder? We’ve got you covered
Our managed services team can help you set up and run your SMS API quickly. From initial configuration to testing and live deployment, we’ll make sure everything is in place so you can start sending messages with confidence.
“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.”
Riccardo Dawson – Chief Operating Officer, Software at Houseful
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
Security and compliance
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.
SMPP gateway access
High throughput, low latency connectivity for seamless bulk SMS integration.
One-time password (OTP)
Verify users quickly with secure single-use SMS codes for logins and transactions.
Appointment reminders
Reduce missed appointments with clear and timely SMS reminders.
Scheduling & throttling
Send the right message at the right moment for maximum impact.
Two-way API
Customers can reply to your text messages for support, confirmations, and updates.
FAQs
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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.
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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.
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What kind of support is available during and after integration?
You’ll have access to support from our expert team, plus free setup assistance if you need it.
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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.
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What programming languages are supported?
Our SMS API supports multiple languages including cURL, C#, PHP, Java, Ruby, Node and Go. Find out more in our developers’ section.
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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.
Let’s start sending, together.
Discover the full power of our mobile messaging platform.
