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Low cost SMS API for developers

Pay only for delivered messages

Lowest cost per delivered text

Free account, with 50 free test credits


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Most SMS API companies charge for undelivered texts

At The SMS Works, we only bill you for delivered text messages. It's a fairer and more transparent way of working.


Why choose our SMS API?

The SMS Works SMS API allows you send SMS and manage messaging programmatically

But with so many providers to choose from, how do you decide which one is right for your business?

This 1 minute video exposes a 20 year-old SMS industry secret that most companies aren't aware of.

We'd love to become your SMS API provider.

Here are 10 reasons why we hope to make your shortlist...


1. Remarkably low SMS API pricing

Our prices are amongst the lowest in the UK. Message costs start at 1.50 pence + VAT per text with our credit doubling offer.

On average, our customers save over 30%. Compare us with other SMS Gateway companies on our price comparison table.

For high SMS volume customers, sending and receiving over 50,000 texts a month, we offer even lower rates.

With our free SMS API, you only pay for SMS credits; there’s no contract or minimum order.


 SMS price comparison tool

SMS API prices
Copy and paste SMS API code snippets

2. Copy & paste API snippets

We’ve put together a comprehensive range of ready to go scripts in the most common languages. Simply copy and paste.

Whatever your preferred language, our goal is to make your SMS integration as fast and simple as possible.

Our rest API documentation is concise, clear and packed with helpful advice and sample code. Your SMS API UK test account comes with 50 free test credits.

 SMS API Developer Zone


"I'd recommend them to anyone looking for a new SMS service provider."

Mike Atkinson - Technical Director, AutoSLM.com


3. Fast, reliable, robust

We've invested heavily to make our UK SMS API as reliable as it can possibly be. Our platform has been built to withstand the rigours of the most demanding applications.

Read SMS API testimonials from our customers.

We understand that data protection and security are crucial to you. We've gone the extra mile to ensure that our platform exceeds all the data protection requirements under GDPR. All our data centres and servers are UK based

 Technical Overview

Fast, reliable, robust SMS API
Tier 1 SMS API connections

4. Low cost reply number (long code)

Receive SMS replies to your text campaigns with a low cost reply number. SMS Replies can be routed back to you by email or we can simply post replies to a URL of your choice.

A free 7 day trial allows you to test the long code service before making any kind of commitment.


"We have found their support to be excellent. Nothing is too much trouble."

Andy Meikle - Technical Director, Motasoft Ltd


5. SMS Credits Overdraft

Running out of SMS credits is one of our customers' biggest concerns. The last thing you need is crucial texts to stop because of an admin issue.

That's why we're happy to arrange a free SMS API credits overdraft. If the SMS credits in your account fall below zero, your text messages keep flowing. We'll keep you up to date with low credit warnings too. There is no charge for this service.

No contract SMS API
Tier 1 SMS API connections

6. Reliable Tier 1 connections

We only use the most reliable tier one connections, direct to UK networks. Text messages sent within the UK stay in the UK.

We never use international or SMS grey routes to send and receive SMS. Although low-grade, grey routes may seem like a great, low-cost SMS option, they are notoriously unreliable.

Learn more about SMS grey routes and why you should avoid them.


"Reliably fast SMS send / receive speeds and A+ customer service."

Jaime Arrazola - CTO, migrate.co.uk


7. No nasty surprises

Your test account comes with 50 free credits, so that you can be absolutely sure that our service is right for you.

We won't tie you in with contracts or minimum SMS volumes. We run a simple, pay-as-you-go, SMS API service.

Our aim is to make integrating with our free SMS API for developers as fast and frictionless as possible.

No contract SMS API
Pay only for delivered SMS

8. Only pay for delivered messages

We only charge you for delivered messages. Failed texts are credited straight back to your account.

Almost all SMS companies charge for failed texts, when they haven't been charged themselves. You can save you as much as 18% by not paying for undelivered texts.

Our delivery reports give you a detailed outcome of all texts sent, including refunded SMS credits.


"We have found the platform to be 100% reliable."

Ian Zucchi - Product Manager, TISSL Ltd


9. Credits don't expire

Once you've bought SMS credits from us, they won't expire. Surprisingly, some SMS providers remove your credits if they haven't been used after 12 months.

Current credit levels can be checked at any time, using our simple delivery reporting tools.

 Set up a free API key

SMS credits don't expire
Pay only for delivered SMS

10. Really sharp and attentive support

Sometimes, you'll have questions that aren't quite covered by the https API documentation. When that happens you'll want a quick response from someone who can answer your questions.

That's why we always get back to customer support questions within the hour. Our objective is to have you up and running with your SMS integration in the shortest time possible.

"Your efficiency is always astounding. Thank you!"
Ian Zuckki - Tissl

Working with The SMS Works has been an excellent experience from day one. They are very responsive to requests and we have found the platform to be 100% reliable. Pricing policy is really fair and very competitive. We also love how easy it is to manage credits online.
SMS API prices
Ian Zucchi, Product Manager, TISSL Limited
We're very happy with the service offered by The SMS Works. SMS delivery is always fast and reliable, and we haven't experienced any downtime or undelivered messages.
SMS API prices
Animesh Chowdhury, Director, The Good Till Co.
We use The SMS Works to send SMS messages to customers in the car buying process. We send thousands a month and The SMS Works have provided us with a fast and reliable SMS service for our application. I'd recommend them to anyone looking for a new service provider.
SMS API prices
Mike Atkinson, Techical Director, AutoSLM.com

SMS API features and tools

Our Rest API is stacked with tools, designed to make working with us as simple as possible. Whether you’re a freelance developer or working in a large team, our tools are quick and easy to use.

You can also use our email to SMS gateway to send SMS notifications and alerts

Full documentation for all of these tools can be found on our Developer Zone.

SMS Delivery Reports

Delivery reports

Every SMS marketing campaign you send generates a delivery report. Delivery reports can be accessed both via the HTTPS API and by logging into your account.

Schedule a text campaign

Schedule a text campaign

SMS via API campaigns can be scheduled to run on the date and time of your choosing.

Receive SMS replies

Receive text replies

Receive SMS replies to your texts using our virtual mobile numbers. Incoming texts can be forwarded to an email address or URL of your choice.

Tagged SMS campaign

Tag your campaigns

Tags or JSON metadata can be added to your outbound texts, allowing you to easily identify specific campaigns. Tags can also be used to identify different accounts, branches or customers.

Batch SMS send

Batch send SMS

If all of your contacts should receive the same text, then the batch send tool allows you to send a bulk SMS campaign.

Retrieve SMS Messages

Retrieve messages

Retrieve text messages that match any given search criteria, either via the API or admin screen.

Dynamic SMS Sender ID

Dynamic Sender ID

Send SMS messages with your chosen originator. There are no restrictions and you don't need to register your sender IDs in advance. (Max 11 alphanumeric or 15 numeric characters.)

Send Long Text Messages

Send Long Messages

A standard text is 160 characters long. Our SMS API allows you to send SMS and receive SMS messages of up to 1280 characters. Long text messages arrive as one text on the mobile phone.

International SMS

Global SMS

We connect with networks in over 200 countries. Wherever you're planning on sending and receiving SMS, we'll be able to deliver.

SMS error codes

Comprehensive error codes

To help you fully understand why a text is undelivered, we provide more than 25 error codes. This vital data can be used to clean your contact data.

SMS API Documentation

SMS API documentation

Our docs are comprehensive and easy to follow. We have code snippets in whatever language you choose and we’re always on hand to answer any queries you may have.

SMS credits overdraft

SMS Credits overdraft

Remove the worry of running out of credits by organising an SMS credits overdraft. An SMS overdraft is free and allows your account to keep sending text messages when your account hits zero.

Copy and paste SMS API code snippets

What can an SMS API be used for?

SMS sending servcies have traditionally been seen as a marketing tool and it’s certainly a highly effective way of getting your message in front of your target audience.

But there are so many other ways that you could use a business SMS service in your business. The uses outlined below are by no means a complete list but could give you some ideas.

 SMS Delivery Notifications

Let your customers know exactly when and where to expect delivery of their order. This can hugely reduce delivery failure rates.

 SMS for 2fa (2-Factor Authentication)

Improve your security by using 2FA SMS. Use SMS to send and receive dynamic codes for secure login or payment transactions.


 Text Appointment reminders

Reduce the number of ‘no shows’ by sending an SMS appointment reminder 24 hours before appointment dates. Missed appointments can be reduced by up 70%.

 Job opportunity alerts

Inform candidates about new jobs opportunities with well-timed text alerts. Include an SMS reply option so candidates can register their interest.


 SMS Customer surveys

Gather valuable customer opinion data with short surveys by text. Use the data to improve your customer service and satisfaction.

 Text order confirmation

Inform customers by text that their orders have been received. Using an SMS HTTPS API, the text can include items ordered and total paid.


 SMS customer support

Handle customer support and queries by text. Provide instant support and improve your customer satisfaction.

 Event invitation

Increase attendance at your events with a personal invitation by text. Offer discounts to those that respond by SMS.


 Highlight important emails

Increase read rate of your emails by drawing attention to important emails by SMS. Email read rate can be increased by as much as 55%.

 SMS Workflows

Connect The SMS Works with other applications using Zapier. No coding is required. It’s a quick and easy way to automate sending an SMS.

Pay only for delivered SMS

What is an SMS API?

An SMS API (Application Programming Interface) is a set of tools which allows the capabilities of one computer application to be made available to another, so that SMS messages can be sent and received.

The API specifies how software components should interact and follows a set of predefined rules, allowing developers to build SMS-based workflows into their own applications.

How does an SMS API work?

An SMS HTTPS API simplifies the whole process of sending a text from a system to a mobile handset.

It acts as a bridge between your organisation and your customers or members of staff.

The SMS API removes the hassle of having to write and deploy specific code to handle the complexities of multiple mobile phone networks that operate different protocols and infrastructures.

For a more in depth description, take a look at our simple explanation.

Customers ask us:

As much as you need.

Our job is to make integrating with our SMS API as painless as possible. That might mean just answering a few simple questions or giving a few pointers. But it could mean getting much more involved.

For one client we were able to implement a new volume reporting tool for them that provided more detailed, end of month SMS reporting.

During our office hours, we expect to handle support request within 60 minutes. If we need to do some additional development work then it might take longer but we’ll always produce a solution as quickly as we can.

Our office hours are 0830 to 1730 UK time.

Running out of credits is one of the most common concerns. We have 3 ways that we can help.

Low SMS credits warning – receive daily email alerts when your account falls below a set level.

SMS overdraft – agreed in advance, this allows your account to run below 0 credits. We normally set the level to be around 2 weeks of typical SMS usage.

Contact us – if your account does run out of credits, then contact us immediately and we’ll add credits so that your systems can run as normal. Our approach is to get the SMS traffic flowing first, account admin later.

In 2019 our SMS API had zero downtime.

Obviously, we can’t be responsible for the performance of the mobile networks themselves but for the areas that we can control, there were no issues.

If we distilled our benefits into 5 simple points, they would be these…

  1. Pay only for delivered texts; all failed SMS are refunded. Zero wastage SMS.
  2. Lower cost per delivered text (SMS prices have dropped by over 50% in the past 10 years).
  3. Built with reliability at its core: zero downtime in 2018.
  4. Clear simple documentation, with code snippets in your chosen language.
  5. Speedy, detailed and attentive support.

Yes, you can. Please see our international SMS tariff for a full breakdown of territories and costs.

Of course, no problem. We can provide you with a  low cost reply number.

Replies are routed back to a URL of your choice and or email. This can be configured in your free account.

We provide support, documentation and code examples for the following programming languages:

PHP, Java, Node.js, Python and Ruby.

Sending SMS texts using PHP script remains the most popular method.
 All the documentation can be found on our developer's page.

SMS credits can be purchased by credit / debit card or by bank transfer. In some case we also have a post-paid option. Please talk to us. Credits don't expire.

For each and every message that you send, you can pick up detailed and accurate SMS delivery reports.

SMS Delivery reports will tell you precisely what happened to your message. If the mobile number is correct and active on the mobile network, then the message will be delivered.

If a message is not delivered there could be number of reasons. In fact, we have 25 error codes that tell you precisely the cause of non-delivery.

These 25 possible outcomes are split into 2 groups, permanent and non-permanent errors.

The aim is to provide you with as much transparency as possible so that your systems can react in the most appropriate way.

No, we don’t constrain the number of messages that can be sent over a given period.

If you'd like to send a message to lots of recipients, you can send those in one batch to be sent either immediately, or on a schedule that you specify.

Is there such a thing as a free SMS API?

No! The SMS gateway might be free, but there will always be cost to send the text messages themselves.


Changing SMS API provider is not an appealing prospect for most.

There are additional costs in integrating with the new supplier and there is always a danger that the new company doesn’t perform as expected. We understand these concerns and wanted to try and put a couple of fears to bed and explain why the benefits outweigh the risks.


SMS API Integration

Fear 1: Time taken for SMS integration

In our experience, this is never as bad as feared. Most Rest API companies have similar approaches and often the code changes required are quite modest.

Our copy and paste code snippets go a long way to simplifying the process and we’re always on hand to help out if needed.


SMS API Reliability

Fear 2: Reliability

Customers tell us that above everything else, reliability is the single most important factor; even more crucial than SMS API price. We really understand this and we’ve put in the work to make sure that everything’s in place to provide the best SMS API online possible.

For a quick summary, take a look at our technical overview.

Our SMS Integration Kit contains all the tools you need to get up and running, fast.

Kit Details

Free account with 50 free credits

Our REST API allows you to send and receive text messages as well as tracking the delivery of the messages you have sent. You can also retrieve your SMS message history by accessing comprehensive SMS delivery reports.

Your free SMS API account comes with 50 free text credits for testing. Our copy and paste code snippets in your chosen programming language mean you’ll be up and running in no time.

Free unique reply number

We'll provide you a unique reply phone number, free, for life . This will allow recipients to reply to the texts they receive.

The virtual mobile number is not shared with other users but is unique to you. Other SMS API providers charge as much as £15 a month for each reply number.

Replies are routed to a URL that you specify in your account. Incoming texts can also be sent to you via email. Free keyword on our shortcode 88440 keyword on a shortcode allows you to add a text response option to your marketing channels, e.g. Text INFO to 88440 to receive a discount voucher. Incoming texts are sent to a set URL and or email.

Double SMS credits offer

New customers buying 500 SMS credits or more will receive an additional 500 credits completely free of charge.

This means that your first purchase could cost as little as 1.45 pence + VAT per text.

Unlimited Support

We're here to provide you with as much support as you need to get up and running with our SMS API. We expect to handle all our support requests within the hour.

Pay only for delivered SMS

The SMS Works offers a fairer approach to pricing

SMS API Pricing has dropped by 63% since 2001.

Our latest research reveals that 20 years ago it cost about 9.7 pence to send a business SMS to a mobile number. In 2020, it costs around 3.5 pence.
That’s an astonishing drop. In almost all cases, SMS providers simply aren't passing on the price reduction to customers.

Also, paying for undelivered texts when your existing provider doesn’t, isn’t a very open way of operating.

By looking at your SMS delivery reports you’ll be able to see how much you’re currently spending on failed texts.

Over the course of a year, it’s likely to be a reasonable amount. Our delivered only pricing means you only pay for what’s delivered so there zero wastage.

Page content by Henry Cazalet

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