Glossary · Carriers and wholesale
Telecom API
In one sentence
A telecom API is a programming interface that lets software control communication services: place or receive calls, manage phone numbers, send SMS, pull call history or get notified in real time when something happens on a call.
Also known as : telecom API · telecom APIs · telephony API · telephony APIs · voice API · voice APIs
What is a telecom API?
An API (application programming interface) is a documented way for one piece of software to ask another for a service. A telecom API exposes the functions of a carrier or phone platform. Instead of someone clicking through an admin portal, your CRM, ERP or website sends a request and gets the result back.
Uses fall into three groups:
- actions: start a call, transfer it, hang up, send an SMS, order a number;
- data: pull call logs, durations, recordings, queue statistics;
- events: be told the moment a call arrives, is answered or ends.
APIs are the foundation of CPaaS services, and also of integrations between a cloud PBX and business tools.
How it works
Most modern telecom APIs follow REST conventions. Your software sends an authenticated HTTPS request (API key or OAuth token) with JSON parameters and gets a JSON response. For events, the service calls a URL in your application, a webhook, each time something changes. Real-time audio travels another way, for example with WebRTC when calls run inside a browser.
Before building on an API, look at the documentation, rate limits, error handling, sandbox environment and where data is hosted, which matters under GDPR.
Example
A solicitors’ firm in Belfast wants every client call to appear in its case management system. When a call comes in, the phone system’s webhook sends the caller’s number to the case software, which pops up the matching file on the fee earner’s screen, a classic CTI screen pop. When the call ends, a second webhook adds the duration and the handler to the file, so time can be recorded. Each evening a short script pulls the day’s missed calls through the API and creates call-back tasks for the morning.
None of this required changing phones or retraining staff: the integration sits between two systems the firm already used.
Telecom APIs at Universal Telecom
Universal Telecom developer APIs let you drive calls, numbers and events from your own software and connect telephony to your CRM. If your project is about analysing what is said on calls, that is AI territory: see automatic transcription on utio.io.
Frequently asked questions
What can I do with a voice API?
Typical uses are click-to-call from a CRM, logging every call against a customer record, buying and configuring numbers automatically, masking numbers between two parties, and triggering workflows when a call is missed.
What is a webhook in a telecom API?
A URL in your application that the telecom service calls when an event happens, such as an incoming call, a call ending or a text arriving. It keeps your software up to date in real time without constantly polling the API.
Is call data from an API personal data?
Yes. Phone numbers, timestamps, durations and recordings are personal data under UK GDPR and EU GDPR. You need a lawful basis, a retention period and a data processing agreement with the API provider.
Related terms
- CPaaS
CPaaS (communications platform as a service) is a cloud service that provides communication building blocks, such as voice calls, SMS, WhatsApp, video and phone numbers, as APIs that developers embed in their own applications.
- CTI (computer telephony integration)
CTI (computer telephony integration) connects the phone system to business software, so the caller's record appears when the phone rings and you can dial a number with one click.
- CRM integration
CRM integration connects a business phone system to customer relationship management software, so the caller's record opens when they ring, staff dial with one click and every call is logged automatically.
- A2P SMS
A2P (application-to-person) SMS is a text message sent automatically by software to a mobile user, such as a one-time passcode, delivery update, appointment reminder or marketing offer, through a messaging platform connected to mobile networks.
- WebRTC
WebRTC is an open standard built into web browsers that lets people make voice and video calls from a web page with no plug-in or app to install, with encryption always switched on.
- Cloud PBX
A cloud PBX is a business phone system run by a provider in its data centres. Extensions, IVR menus, queues and call routing are managed from a web portal, with no PBX hardware on site.
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