Man texting in office

The Complete SMS API Resource

This complete guide to SMS APIs covers all the topics that will help you choose and then make the most of your integration.

As well as containing lots of invaluable insights, it also providers a complete listing of all SMS API providers in the UK and worldwide.

We hope you find it useful.

The guide is broken down into 17 sections

  1. What is an SMS API?
  2. What’s the difference between an SMS gateway and an SMS API?
  3. How does an SMS API work?
  4. Are SMS API companies generally reliable?
  5. 4 tips for choosing an SMS API supplier
  6. How much does it cost to send a text through an SMS API?
  7. Are there any free SMS APIs?
  8. Pros and cons of using an SMS API
  9. What can an SMS API be used for?
  10. Should I use SMPP or HTTP for sending SMS through an SMS API?
  11. What technical knowledge and skills do I need to be able to use an SMS API?
  12. Great example of an SMS marketing message sent via an SMS API
  13. What are the main SMS API features and tools?
  14. Mistakes to avoid when using an SMS API
  15. What are the regulations for sending SMS via an API?
  16. Listing and review of top SMS API gateways
  17. Complete list of SMS API companies

What is an SMS API?

desk lamp

An SMS API (Application Programming Interface) is a set of tools which allows computer applications to communicate with each other so that SMS can be sent and received.

The API specifies the rules and protocols by which the computer systems interact with each other.

So an SMS API refers to the compatible set of tools that allow you to send and receive A2P SMS.

A really concise and easy to understand definition of an API was posted by Mulesoft:

What’s the difference between an SMS gateway and an SMS API?

Key for clockwork

There’s no real difference between the terms SMS API and SMS gateway. The two terms are completely interchangeable. Pedants will argue that for precision, you need to use the correct term to avoid potential confusion.

The only minor nuance is that an SMS Gateway refers specifically to the sending of an SMS to a mobile phone network.

It’s often seen as a slightly less technical alternative to SMS API.

How does an SMS API work?

Iphone with SMS Works logo

The function of an SMS API is to simplify the whole process of sending a text message from a company to a customer’s mobile number.

With so many providers, the individual mobile networks (e.g Vodafone or EE) couldn’t possibly deal with the huge number of potential integrations. (There are literally hundreds of SMS providers.)

So they appoint global SMS aggregators who deal with individual SMS delivery providers.

There’s a 4 step process for sending a text from company to a client mobile phone.

  1. Company sends text message via SMS API to SMS API provider.
  2. Provider sends SMS to SMS aggregator
  3. SMS aggregator sends message mobile phone network
  4. Mobile network delivers SMS message to mobile number

Are SMS API companies generally reliable and what are SMS grey routes?

Oak tree

The overwhelming majority of providers are very reliable indeed. Reliability is almost always  customers’ most important priority when choosing a SMS API company.

15 years ago there were a number of providers that routinely used SMS grey routes for their SMS send. Although low priced, SMS API grey routes are painfully unreliable and suffer from delays, lack of delivery reports or worse still just not delivering messages at all.

SMS grey routes make use of back door routing onto mobile networks, disguising business SMS as consumer, peer to peer texts.

Despite grey routing costing the mobile networks $5.9 billion annually, the problem is less serious than it used to be.

An SMS provider’s pricing can help give buyers a clue as to whether they get involved in grey routing of any sort. If the company has a 2 tier pricing structure such as ‘standard routing’ and ‘critical routing’, then it’s probable that the standard route uses a grey route to send SMS,

Don’t forget that companies do not own the mobile networks. if there’s a major mobile network issue, then the SMS gateways will be powerless to do anything about it. O2 suffered such an outage in parts of the UK as recently as November 2020.

4 tips for choosing an SMS API supplier

With so many SMS API companies to choose from, how do you select one that’s right for you?

Thankfully, the overwhelming majority of suppliers are honest and offer a reliable SMS delivery service at a sensible cost. These tips will help you choose a reliable SMS company that’s a perfect match for you.

Be aware that SMS Providers are not the same as SMS aggregators. SMS aggregators connect directly to mobile phone networks.

1Choose an SMS supplier that’s based in your country

Almost all SMS companies can deliver SMS delivery internationally but they will be most familiar and have the greatest experience in the country in which they are based.

Local laws on sending SMS vary dramatically round the world, so choose a company that has the local experience.

Most US based companies for example are simply unaware of how SMS marketing works in the UK and often try to charge for things that should be free, like setting the sender ID of the message, for example.

By choosing a local company, you’ll also likely to get a better price, along with support that matches your time zone!

Check whether your SMS credits expire

A surprising number of SMS API providers remove your credits if you don’t use them after a certain period, usually 12 or 18 months.

This information is often deeply buried in the terms and conditions. Dig a little deeper and find a company that doesn’t expire your SMS credits.

Thoroughly check the SMS API documentation

Before purchasing send SMS credits check that the documentation meets your expectations. You should expect code examples in the coding language that you use and detailed explanation of the tools and their functionality.

Have a good rummage and make sure you’re comfortable with everything before committing.
It goes without saying that you should have a free HTTPS API test account to check your code before purchasing credits.

You should expect code examples in the coding language that you use and detailed explanation of the tools and their functionality, usually through a portal developer.

Check if you’re paying for non-delivered texts

Surprisingly, most SMS gateway companies charge their clients for failed text sends, when they are not charged themselves.

Try and find a supplier who refunds non-delivered texts. It’s a fairer and more open way of working.

How much does it cost to send a text through an SMS API?

Research has shown that the average cost to send an SMS has dropped by around 65% in the past 10 years or so. There’s far more competition and SMS prices have tumbled, making it a great time to start. if you haven’t already got involved.

Business SMS prices over time

SMS price tag

The sharp drop in prices in 2010 was due to a new ‘credit doubling’ offer introduced by Text Marketer which was then swiftly adopted by many other SMS players.

Credit doubling for initial SMS credit purchases quickly became the norm.

Watch the video below to learn about 3 things you might not know about SMS API pricing

SMS price comparison web tool

To help buyers assess different SMS providers, The SMS Works has developed an SMS price comparison tool.
The free tool allows you to compare up to 10 SMS providers and highlights the best value provider.

SMS cost comparison calculator

You can then also download the results for later use.

SMS API pricing comparison table

The following SMS API pricing comparison chart gives you a rough idea of what you might expected to pay for SMS credit bundles in 2020 and 2021.

(Please bear in mind that this is not a complete lost of all providers. Prices were taken from the relevant website and were accurate at the time publishing.)

Company Website Bulk SMS Price per text for purchasing 1000 text credits Do they refund non delivered texts? Cost for unique reply number Do SMS credits expire? Head Office Location
Bulk SMS 4.5p No £7.50 No South Africa
Text Marketer 3.8p No £10 No UK
Voodoo SMS 2.9p No £10 No UK
Text Local 4.9p No Cost not available Yes UK
Sendmode 3.4p No Cost not available Yes Ireland
Esendex 6p No Cost not available No UK
Reach Interactive 3.2p No Cost not available Unknown UK
Fire Text 4p No £5 No UK
Text Anywhere 4.9p No £25 Yes UK
Text Magic 4p No £2.50 Yes UK
Mobivate 3.28p No £35 Unknown UK
Clickatell 3.5p No £8.33 Yes South Africa
World Text 6.4p No £25 Unknown UK
Kapow 6.25p No £50 Yes UK
Text Burst 4.5p No Cost not available Yes UK
Intellisoftware 6.2p No £16.50 Unknown UK
2SMS 10p No Unknown Yes UK

Are there any free SMS APIs?

SMS price tags

Almost all SMS APIs are free in the sense that there is no charge for use of the tools themselves. But all providers charge an amount per text, for the actual SMS send.

The mobile networks charge what is called a termination fee for each message sent. This is the cost to deliver a text from one network to another. So there are real costs to the SMS providers for delivery of SMS, which in turn means there are no free options.

In the early 2000s, a few companies experimented with the concept of offering a free SMS service funded by advertisers who used 60 out of the 160 characters for their messages.

This meant that each text contained messages from two companies.

The result was that client just became confused about who the message was from and the idea was abandoned.

Pros and cons of using an SMS API

Companies have been using SMS gateways to communicate with customers and staff since the mid 90s.

Despite new platforms like WhatsApp and RCS, SMS is still by far the most popular messaging channel available.

According to Juniper research business SMS volume will increase by 7% between 2019 and 2020, from 3.2 trillion to 3.5 trillion texts.

Chart showing the number of A2P SMS sent

Advantages of using an HTTPS SMS API

Sending SMS is automated – Once integrated, SMS can be programmatically sent based on events or certain time triggers. For example ca text can be sent 24 hours before an appointment.

Each SMS is personalised – As opposed to sending a bulk SMS, where every message is the same, using an SMS API, each message can be tailored to the individual.

Delivery reports provide tracking – Each messages can be traced with a delivery report, providing detailed visibility of which have been read.

Quick to set up – Most companies, gives clients free text accounts, with free SMS credits for testing. Copy and paste code snippets make for quick and east integration.

High open rates – Compared to email, SMS has far higher open rates meaning your message is far more likely to be read.

Downsides of using an SMS API

Just 160 characters – It’s challenging to get your message across in just 160 characters. Most platforms allow you to send longer messages but you’re still limited to a short sentence or two.

It’s a technical service – To set up and integrate an HTTPS API requires that you have a technical background. You need to be comfortable handling APIs and have some understanding of coding. It can’t be implemented by everyone.

SMS can be seen as invasive – Not everyone loves texts. Make sure you don’t bombard your customers and include an opt out in all the texts that you send.

What can an SMS API be used for?

There are almost countless ways that organisations use SMS delivery to communicate. It’s fast, efficient and low cost. Here are some of the more common uses for an SMS API

SMS Delivery Notification

Notify customers of a parcel or document delivery.

SMS for 2fa (2-Factor Authentication)

Increasingly companies are improving security on their payment and accounts systems. Sending a 2fa SMS is a low cost and efficient 2fa option.

SMS Appointment reminders

Many customers now expect SMS appointment reminders and they can reduce ‘no-shows’ by up to 70%.

Job availability alerts

Recruiters have been using SMS job SMS alerts for years, it’s one of the most effective way of keeping job seekers in touch with new roles.

SMS surveys and polls

SMS client satisfaction and opinion polls are a great way to improve your customers service. It’s a terrific way to increase customer engagement.

SMS order confirmation

A simple confirmation text, sent via an SMS API, can include products ordered and delivery timing.

Client support by text

Allow your customers to ask questions by text and respond to them, via your outbound SMS gateway.

Highlight important emails

Draw attention to important emails by backing them up with a text. Read rates can be improved by 55% with an SMS follow-up.

SMS Workflows

Integrate your workflows by SMS-enabling your apps with services like Zapier.

Server alerts

Receive an SMS when a server is down or has exceeded a set threshold.

Should I use SMPP of HTTP for sending SMS through an SMS API?

Key for clockwork

Which protocol you use for sending SMS does depend on how you’re planning to use. There’s no definitive answer but SMPP is certainly a more complex option than HTTP. Here are the main considerations

SMPP has stood the test of time for sending and receiving SMS, and it is a very stable API.

It’s also a very low-level API, which exposes all of the foundational elements of SMS without abstracting them into nice easy methods.

Using SMPP, you’ll need to handle long messages yourself, for example, stitching longer texts back together when you’ve received all of the parts.

SMPP response handling also requires parsing ASCII text and breaking out the message headers from the body, which is not something most developers are used to.

You’ll also need to handle the GSM character set, discerning whether messages contain permitted characters or not, and optionally using a different encoding to send messages.

Not every programming language has a nice SMPP wrapper, which is also something to consider.

You’ll probably end up writing twice as much code, which is effort you could be putting into building on the value that a simple HTTPS API provides.

Good HTTP APIs will abstract out all the quirks of SMPP, normalising things like message stitching, error codes and character sets.

What technical knowledge and skills do I need to be able to use an SMS API?

Once you’ve set up your account and generated your API key, there are a few basics that will get you most of the way with any modern HTTP API, and they all apply to SMS APIs too:

1 Becoming familiar with authentication methods like Bearer or JSON Web Tokens.

2 Using server-side request libraries like Guzzle or Axios, so that your code can run behind your firewall, without exposing your authentication details in a browser.

Handling async calls and callbacks.

Building and managing webhooks, so that services can update you asynchronously with changes.

5 You have a choice between using SDKs which will provide comprehensive classes, provide the full range of functionality and error handling, that you can import into your packages, or just making simple cURL or HTTP requests, depending on your use case.

Most APIs should allow you to get up and running in a morning or even less, if you’re familiar with these things (and the documentation is helpful!)

Phil – Technical Director, The SMS Works

Great example of an SMS marketing message sent via an SMS API

We recently came across a near perfect example of a marketing text sent by an SMS API. Kwik Fit, a UK garage chain, had managed to merge 6 separate pieces of data in the text. Quite a feat. What makes this marketing text so good? The inforgraphic below explains.

Plenty more sample SMS marketing texts, broken down by industry sector can be found in this SMS marketing library.

Kwik Fot MOT reminder

What are the main SMS API features and tools

Here is the minimum set of HTTPS API features that you should look for when choosing an partner.

Long messages
A standard SMS contains only 160 characters. Long texts allow you to stitch together a number of texts, so that they arrive on the recipient’s mobile as one message rather than a string of individual texts.

Dynamic sender ID
Set your sender ID. This is who the message is from. 11 alphanumeric characters can be used or 15 numeric. Note that in many countries you are not permitted to control the sender ID, messages must come from a local long code. 

This allows you to identify each individual message. You might want to tag a message to a branch, account, region of individual.

Delivery reports
Delivery reports are crucial for tracking your campaigns and help you identify mobile numbers that are incorrect. You can view all the messages sent and the relevant outcome,

Schedule date
Allows you to set a date and time that you want an SMS to be delivered.

Batch send
Send texts in blocks if the same message is being sent to many individuals.

Receive replies
Allow clients to reply to the texts that you send. Replies can be routed to a URL or sent by to an email address. Replies sent from an end user’s phone to an organisation are known as MO SMS messages.

URL shortener
This allows you to reduce the number of characters in the your web addresses, freeing up more characters for the message itself.

Mistakes to avoid when using an SMS API

It’s so easy overlook some crucial details when setting up your SMS API integrations. This list of errors will help you avoid the obvious and not so obvious foul ups that others have made before.

Definitely worth a quick read, it could save red faces in the IT department.

Check you’re using the GSM characterset
Most SMS gateway s use the GSM characterset for transmitting SMS. If you use non-gsm characters it’s likely that your message will be sent using UTF-16 encoding which has a maximum of 70 characters per text. The result – you’ll end up using more text credits that you intended. The SMS Works has developed a free unicode detector tool to help you identify and eliminate non-gsm characters

Check your message length
A standard text is 160 characters. Stray just 1 character over and you’ll be using 2 credits rather 1 and your message will be sent using concatenated SMS. You have been warned! This free SMS length calculator will identify how many characters are in your message and how many SMS credits are needed to send the message.

Set up a low SMS credits warning
One of the biggest fears for SMS API users, is running out of credits. Make sure you set up a low credit warning so that you can take action before your post HTTPS API stops working.

Triple-check your code
Go the extra mile in checking your code works in all scenarios. What events could happen to break it? Try and foresee any potential issues and get them covered.

Are SMS replies being handled correctly?
If your integration has a reply functionality make sure that these are being routed in the way you want. Is your platform processing the replies correctly?

Don’t accidentally invalidate your API Key
It’s all too easy to generate a new API key, invalidating your old one and stopping your texts from being sent.
Once you’ve got your API key, stick with it.

Check international message costs
Do you send international SMS? If you do, make sure you understand and have taken account of international SMS costs, they are often higher than domestic SMS rates.

White list email domains
SMS providers will probably be sending a number of important email alerts to you like low SMS credits warning, incoming SMS alerts etc. Make sure that the relevant domains are whitelisted, so emails don’t end up in spam filters.

Check your mobile data is accurate

Using an HLR service, you can check that your mobile database contains live numbers before sending your campaign. Dead number will be highlighted and can be removed.

What are the regulations for sending SMS via an API?

ICO logo

When GDPR came into force in May 2018, the rules for sending SMS became much tighter.

Organisations had to be able to prove that customers had opted in to receive texts from them.

It was no longer acceptable to leave tick boxes checked, consumers had to actively opt in.

In the UK, the data authority now takes a much tougher stance on companies that break the rules on SMS.

They have the power to hand out large fines of up to 4% of global turnover or 20 million Euros.

The main principle that the ICO outlines on it’s website is as follows.

“You must not send marketing an email address or texts to individuals without specific consent. There is a limited exception for your own previous customers, often called the ‘soft opt-in’.”

For marketers, this means that it’s even more important to ensure that your campaigns don’t break the rules. The consequences could be alarmingly serious.

Wherever you’re planning SMS send campaigns, make sure that you’re following the guidelines in all the countries that you’re sending to.

Listing and review of top SMS API gateways

To help you navigate the vast numbers of companies with SMS capabilities, we’ve put together of review of the top 10 SMS companies and then a complete listing of all other suppliers.

Have we found them all? Contact us if you chosen supplier isn’t listed and we’ll get them added.

The top 10 list doesn’t represent an endorsement in any, they are simply the most dominant and largest providers in the market.

Review of top 10 SMS API providers.


Twilio logo

“Connect with customers everywhere they want to interact with you—from texts to emails, phone calls to video, intelligent chatbots and back—within a single powerful platform.”

Head office USA
Core products SMS, email, voice, whatsapp, video
Cost per SMS $0.04
Refund non-delivered texts No

If you’re looking for an integrated enterprise solution that combines SMS, email, voice and whatsapp under one roof, you’d struggle to find a better solution than Twilio.

Their set of tools can handle the most complex integrations. They’re right at the cutting edge of what’s possible.

Twilio’s APIs (Application Programming Interfaces) power its platform for communications. Behind these APIs is a software layer connecting and optimizing communications networks around the world to allow your users to call and message anyone, globally.

Any down sides?

Twilio are a US based company aimed at international enterprises, so you might not expect a deep level of understanding of how SMS operates in specific territories.

Twillio are massive and you might find that their support is not as rapid or as personalised as other providers. They’re great for global enterprises, not so great for small businesses looking for personalised support.

Trust pilot gives them a disappointing review score of 1.6/5.0

We’ve also written a brief article about why you should consider using The SMS Works as an alternative SMS API to Twillio.


Plivo logo

Connect and engage with your customers globally
Plivo’s voice and SMS platform enables businesses to create and deliver better customer experiences.

Head office USA
Core products Voice, SMS, MMS
Cost per SMS (to send to UK mobile) $0.033
Refund non-delivered texts No

Plivo have an impressive set of SMS, voice and MMS tools and rather like Twilio they seem set up to cater from global enterprises rather than small businesses

The documentation is well set out and most developers would have no trouble integrating with their SMS service quickly and efficiently.

Their service has truly global reach. They connect with networks in over 190 countries.

Any down sides?

Plivo are based in the US and you might find support slightly tricky if you’re based in a different time zone. Their contact page encourages you to fill in a form rather than call. They don’t list a phone number on their site, suggesting they’d rather not actually speak to you.

Plivo have suffered from some reports of shoddy client service and being slow to respond to clients when thing have gone wrong.

Trust pilot gives them a score of just 1.8/5.0

Text Local

Text Local Logo

Smarter customer journeys with multichannel messaging solutions

Head office UK
Core products SMS, MMS, RCS, WhatsApp
Cost per SMS (to send to UK mobile) £0.049
Refund non-delivered texts No

UK based Text Local are predominantly providers of SMS services for business. They one of the longest established providers, having started back in 2006.

They were purchased by US based IMI Mobile back in 2015 but they’ve remained in the UK with their office in Chester.

As well as an easy to use and well documented SMS API, they also have a web based software platform allowing non-technical people to take advantage of the effectiveness of SMS.

Any down sides?

Text Local is arguably one of the UK’s market leaders of SMS services in the UK.

Their platform is solid and their support effective. They score an impressive 4.7/5/0 on Trustpilot

Text Local are however quite expensive, with a text message costing 4.9 pence + VAT. They are also charge their clients for non-delivered texts, when they are not charged themselves.


We’ve uncovered the secrets of winning communications.
5,000 customers in 14 countries shared how they want to connect.

Head office USA
Core products Email, SMS, voice, messaging
Cost per SMS (to send to UK mobile) £0.0363
Refund non-delivered texts No

In 2016, Vonage acquired Nexmo, making it one of the largest global cloud communications companies

They offer a complete set of integrations for email, voice, SMS and all types of messaging. Their aim is to unify client communications and offer a menu of services from which you can pick the elements that you need.

Customers can ‘select from our extensive portfolio of APIs to create your own apps and integrations. Or get the best of both: choose the apps you need and customize them with our APIs. You can’t do that with anyone else.’ A bold claim indeed!

Any down sides?

Vonage state on their pricing page that ‘Pricing is updated every hour and will fluctuate based on carrier costs and current exchange rate (between USD and EUR).’ This ever changing pricing makes it very difficult for users to budget properly. Most large volume users of SMS would not be happy with this pricing uncertainty.

Plenty of customers have had problems with customers service and their rating on Trustpilot is 2.3/5.0

Like almost all SMS providers, they charge clients for undelivered texts.


SMS API logo

Powerful and easy SMS communication
Start sending SMS using SMS API or our user-friendly online interface

Head office Poland
Core products SMS
Cost per SMS (to send to UK mobile) EUR 0.033
Refund non-delivered texts No

SMS API have been around for 12 years are making increasing strides into the UK and EU markets.

They concentrate only on SMS and as their name suggests they manly offer an SMS service although they do have a web based sms send solution. They offer a range of convenient payments options such as BACS and credit card.

SMS API have a number of third party integrations which allows their customers a quick and easy solution for adding SMS to those services, Integrations include Magneto, Zapier and Opencart, amongst others.

Any down sides?

Their pricing structure suggests a flat rate of 3.3 Euro cents per text but doesn’t give you an indication of what SMS price discount you might expect if you purchase higher volumes. There’s an invitation to make contact but more info on the website would be helpful.

They don’t appear to have a UK office, so may not be as familiar with the UK SMS market as other providers. They also charge clients for failed texts.

Clockwork SMS

SMS API logo

The Easy Text Message SMS API
Send and receive SMS through your app

Head office UK
Core products SMS
Cost per SMS (to send to UK mobile) £0.045
Refund non-delivered texts No

UK based Clockwork SMS offer a simple and easy SMS integration. Their offering is easily understood and their documentation, well laid out.

Like most SMS providers, they operate a simple pay as you go service. If required you can also request a post pay solution which means you’ll never run out of text credits or have to up.

Clockwork have integrated with a number of software platforms including companies in the insurance and proptech sectors. They offer support both by phone and email and respond to enquiries within the hour.

Any down sides?

A solid, well established provider but at 4.5 pence + VAT per text, Clockwork are one of the pricier SMS providers. For low volume senders this is probably fine but might not suit larger volume customers.

Clockwork also charge customers for failed texts, so there’ll be some wastage.


Clickatell Logo

Powering chat commerce for forward-thinking global brands.
We lead the transformation of digital commerce and customer engagement through mobile.

Head office South Africa
Core products SMS, Whatsapp, chat, mobile payments
Cost per SMS (to send to UK mobile) $0.0393
Refund non-delivered texts No

Clickatell have been around for over 20 years and were one of the first HTTPS API providers in the world.

They aim themselves squarely at the global enterprise market where they provide SMS and chat solutions for global banks and telecommunications companies.

Clickatell gives global consumer brands the ‘power to reach over 90 percent of the world’s population through mobile messaging and chat.’

They have a self serve SMS platform that encompasses both a web-based SMS software and SMS API solution

Any down sides?

Clickatell’s SMS pricing is confusing. They have a 2 tier pricing model depending on whether your usage is standard or time critical.
Prices provided are only estimates and ‘actual prices are determined at the time you use the online service (e.g., sms send a message).’

Their 3 step registration process may put off some users.

They don’t offer refunds for text purchase made which causes some customer annoyance, even though it’s in their terms and conditions

Text Anywhere

Text Anywhere Logo

SMS: For effective communication
90% of all text messages are read within 3 minutes

Head office UK
Core products SMS
Cost per SMS (to send to UK mobile) £0.05
Refund non-delivered texts No

Purchased by Nottingham based Commify in May 2019, Text Anywhere have been supplying their web SMS and HTTPS API solution to mainly the UK market since 2003.

Documentation and pricing are clear and concise, allowing developers to get up and running quickly. The company offers a simple pay as you go pricing policy and SMS bundles from between 250 and 100,000 can be purchased directly from the website. Support is offered by email and phone.

Text Anywhere offers two types of partner programme, a simple reseller option as well as a white labelled partner programme.

Any down sides?

Text Anywhere is rare in the SMS industry in that it charges a monthly fee for particular packages. It has a ‘business’ package at £30 a month and a ‘pro’ option at £70 a month. Both come with text message bundles.

Their prices start at 5.1 pence, placing them towards the more expensive end of the market. Non-delivered texts are aslo charged for.


Telesign Logo

Prevent Fraud
Know Your Customer
Engage With Users

Head office USA
Core products SMS, voice RCS
Cost per SMS (to send to UK mobile) N/A
Refund non-delivered texts No

Telesign are one of the few SMS providers to lead with a set of tools aimed at preventing fraud and increasing data security. Their offering allows customers to enable SMS 2 factor authentication, prevent fraudulent account take over and reduce fake accounts.

They also have more conventional messaging solutions for SMS, voice and RCS.

Telesign specialise in providing messaging tools to the financial services and gaming sector where security has high importance. They aim for the enterprise customer rather than smaller businesses.

They have an impressive range of blue chip customers including Skype, EA and Salesforce.

Any down sides?

Despite an extensive search, Telesign do not appear to have published SMS pricing on the website. Perhaps global enterprise prospects don’t require an indication of pricing before beginning a conversation.

Telesign charge for failed texts.


Simple Texting Logo

We make it easy, fast and affordable to send SMS marketing campaigns or engage in 1-on-1 conversations with customers.

Head office USA
Core products SMS
Cost per SMS (to send to UK mobile) $0.045
Refund non-delivered texts No

SimpleTexting are are US based SMS software and SMS provider. Their target market is small and medium sized businesses although they do have some enterprise customers.

They mainly serve American companies, although their platform does allow for international sending.

SimpleTexting’s web-based, all in one SMS marketing platform is packed with features like 2-way SMS and link tracking. The documentation is well laid and includes code snippets in the main coding languages.

They offer support by email, phone and chat.

Any down sides?

4.5 cents per text is on the high side, compared to others.

Their US focus and possible lack of international footprint might make them less attractive to companies sending SMS globally

Complete list of SMS API Providers

Have we missed any providers? Send a quick email to [email protected] and we’ll get them added to the list.

OTT in the table below refers to OTT messaging. OTT messaging platforms include WhatsApp, Skype, iMessage etc.

Vendor Description SMS Email Voice OTT
Twilio Use this API to send and receive SMS, MMS, and channel messages, track delivery status, and manage message.        
Text Local Cut and paste our code and your key to start sending and receiving texts in minutes.    
SMS API SMSAPI is a worldwide bulk SMS provider offering reliable solutions, supporting both marketing campaigns and daily notifications.  
Nexmo Vonage’s tool enables you to send and receive text messages to and from users worldwide, using simple REST APIs.        
Clockwork SMS Clockwork is an Easy Text Message API for developers. Build powerful apps and include SMS. Signup is free.  
The SMS Works Easy and fast SMS integration. HTTPS SMS API account comes with free reply number and test credits. Developers love our copy and paste code samples and easy integration.  
Esendex Straightforward and hassle free SMS integration  SendSMS via Rest /Soap API or Form POST API. Free 7 day trial.        
MessageBird Build with or without code. Drag-and-drop builders, or an intuitive point-and-click dashboard.        
Octopush Easily integrate and manage all your SMS send from your software and applications.        
Clicksend Business Communications. Solved. Communicate with your customers and staff like never before on SMS, Voice, Email, Rich Media and so much more. From single to scale by dashboard or API.        
Fast SMS Simple, Powerful, Scalable  Integrate FastSMS features into your own software. using your preferred programming language  
TextMagic Build your web applications with TextMagic SMS API infrastructure. Send and receive bulk SMS, manage contacts, schedule messages.  
Bulk SMS Easily SMS-enable your website, application or customer relationship management platform with our REST API.  
Text Anywhere Capabilities. The Gateway provides you, the software developer, with the necessary building blocks to integrate SMS into your application or website.  
Reach Interactive Our secure HTTPS SMS API is the only tool you’ll need to schedule, send and receive from your existing systems. See our documentation here!  
Plivo Programmatically send and receive text messages. Interact with your customers globally using SMS.      
Ringcentral Send and receive texts from your apps – no phones needed. RingCentral  let you integrate SMS and MMS.    
Clickatell An SMS API allows you to integrate SMS services with your website, third-party application or service, mobile app, CRM etc.    
OpenMarket SMS APIs. Nothing so global ever felt so personal. Give developers total freedom to create perfect customer experiences.    
Text Marketer Feature-rich wrappers make sending or receiving SMS easy and fast.  
8×8 Automate your messaging workflows by scheduling notifications along the customer journey. Start sending immediately using the Campaign Manager        
Gateway API SMS with first-rate services at low prices worldwide. We send over 250 million SMS messages annually.  
Telesign SendSMS Messages. Enables developers to build communications and account security SMS into web and mobile apps.    
MessageCloud If you’re a software developer, MessageCloud’s bulk SMS APIs are perfectly suited to be integrated into your business, whatever your SMS application.  
Sinch Send personal texts to customers around the world, right when they need it.      
Simple Texting From CRM integrations to marketing, and employee communications, our SMS gateway can handle it all.  
Voodoo SMS Send SMS via our powerful HTTPS API. Sending Text Messages  our most powerful API call and has a host of features to empower your application.  
Cosmic SMS Add the capability to  sendmessages to your website with the power of Cosmic SMS REST API.  
Sakari Getting started with Sakari is easy. Using our SMS API quick start guide, you?ll be sending your first text message in just five minutes.  
Sendmode Sendmode will SMS-enable any site or application,with ultra reliable routes and low prices. Use any programming language.  
Mediaburst Mediaburst is a bulk SMS serice that lets you send and receive texts via your own apps.  
Mailjet Send your transactional SMS worldwide and reach your customers at the best time. Benefit from the power of SMS API and the exceptional opening rate    
Bandwidth Integrate powerful SMS into your systems with Bandwidth’s easy-to-use SMS API.    
CDYNE CDYNE’s service easily integrates text messaging into applications.    
Pageone Secure service with all requests being sent through our ‘Oventus’ messaging gateway at up to 256bit encryption.  
Textbelt Use text with a clean, simple gateway. Textbelt is a no-nonsense SMS API built for developers who just want to send MS. Integrate our SMS Rest API and implement SMS Notifications, OTP in your workflows. Get a fully Secure SSL SMS API for environment or development language.  
Firetext Integrating a FireText gateway into your own application is easy with the Developer SMS API kit.  
Message Media SendSMS on time, everytime. Our REST APIs and enterprise-grade text messaging gateway ensures your messages arrive securely.  
ThinQ You’ll be able to leverage and integrate powerful real-time text and multimedia solutions.    
Swift SMS Gateway Net Soap RESTful JavaScript PHP cURL with full dev library and great support. Global reach to USA, Canada, Europe and Australia.  
Telnyx An SMS API is a software interface that allows developers to build code that can send using an Application Programming Interface    
SMSmode Allows you to send SMS directly from a software or application solution.  
SMS Global The HTTP gateway allows you to integrate your Application to SMSGlobal using the HTTP protocol to send SMS. Full HTTP API documentation and 24×7 support.  
Ozekisms Ozeki introduced a new HTTP SMS API (v2.0) in Ozeki NG SMS Gateway v3 to address the requirements of the SMS software developer community.  
Hslsms SMS Send and receive SMS for all your needs. HTTP, SMTP, SMPP and Web Services.  
TxtSync Reliable low cost SMS to power your SMS Marketing Campaigns. Easily integrate our SMS into your existing products and workflows.  
Textmark Go build something amazing. · Our powerful Text Message API allows you to easily SMS-enable your web or enterprise apps to provide on-demand SMS.  
Red SMS It is really simple and straightforward with RedSMS to integrate our SMS  system with your website, software or CRM system.  
Proovi Dedicated SMS send and receiving for everyone. It is very easy to start messaging with our smart API.  
Toucan Text SMS service provider for any sized organisation. Powerful  SMS Online, Email to SMS and SMS Automation software.  
Sendpulse Our interface is used to integrate SendPulse’s distribution service capabilities with client’s personal projects.    
Mobivate This interface allows messages to be sent from your application to any mobile phone. This is known as a Mobile Phone Terminated (MT) message  
123 Txt The RESTful API permits programmatic access to SMS features available on the 123-txt SMS messaging platform.  
Intellisms To use our service simply register and you will receive 5 free evaluation credits.  
Any Text SMS Texting API Gateway for Developers – free, easy and quick set-up. The AnyText Programmers’ API is simple.  
Burst SMS Use our SMS REST API to send and receive text messages through your app or software. Fully documented. Local support. Fast, secure, and reliable.  
Text Global Integrate SMS text message into any application, website or CRM  
faretext Integration, ideal for those needing business-grade texts with multiple functions, have high-volume requirements, and who want something built-in.  
EasySend SMS HTTP API allows you to integrate your system to   
SMS Broadcast The SMS Broadcast API allows you to integrate SMS into your systems. Our API is a simple, yet powerful way to connect.  
24x Easily send SMS, alerts and offers to your contacts, customers and prospects in seconds. Also receive replies from SMS.  
World Text SMS Text Message HTTP REST, SMPP and SMTP APIs and Helper Libraries for Bulk SMS, Inbound and Two-way Text Messaging.  
Kapow With Kapow it is easy to automate sending SMS within existing websites and Software.  
2SMS 2sms offers a range of gateways  
TM4B Our service makes it fast and easy for you to SMS-enable your software, app or website.  
D7 SMS Integrate D7 SMS with your Application. Notify your customers with our Integrations, Extensions and Plugins to smoothen your communication process.  
Textit Easily build scalable, interactive chatbots on any channel without writing any code.  
SMS Fusion Use SMS from the application of your choice through our dedicated servers  
Gateway API Rock-solid. Two-way SMS  
SMS Carrier The service is operated to provide higher reliability and quality of service than available from any individual mobile network’s own wholesale SMS service. Both SMPP and HTTP SMS APIs are provided.  
TXT Nation txtNation Gateway is our Mobile Billing and Messaging – Gateway, empowering you to create your own mobile messaging and billing solutions.  
Isasms Sophisticated SMS communications to reach your whole school community  
Bulkgate SMS gateway that does things right  
Swift SMS Gateway Connecting Applications, Advertising & Alerts To SMS  
SMS Juice SMSJuice helps you to connect to our system and services from your own software and web-based apps.  
SMS Broadcast    
SMS 77 SMS Professional solutions for your company to SMS send and receive SMS.  
cSpoof Create your own tools and services with the cSpoof API  

author avatar
Henry Cazalet Managing Director
Co-founder and Director of The SMS Works, a low cost and powerful SMS API for developers. About Henry