What is Integration Testing? — UK Software Development Guide

4 min readJune 2025ClickMasters Technical TeamReviewed by James Whitmore, CTO
what is integration testing

Direct Answer

Integration testing verifies that different components or modules of a software system work correctly when combined. Unlike unit testing (which tests individual functions in isolation), integration testing checks that the interfaces and interactions between components function as expected.

Integration-testing in the UK

Integration testing is particularly important for UK software that integrates with government APIs. HMRC MTD, Companies House, NHS APIs, and GOV.UK services all have sandbox testing environments designed for integration testing before go-live. ClickMasters runs integration tests against all third-party APIs as part of CI/CD pipelines — ensuring that API changes by government services (which can happen without notice) are detected in staging before they cause production incidents. UK GDPR consideration: integration test environments should use synthetic or anonymised data, not production personal data.

Related Glossary Terms

IR35

IR35 explained for UK software developers and business owners. IR35 (Off-Payroll Working Rules) is UK tax legislation that determines whether a contractor should be taxed as an employ... UK context, examples, and related services.

Read Definition

API

API explained for UK software developers and business owners. An API (Application Programming Interface) is a defined set of rules and protocols that allows different software system... UK context, examples, and related services.

Read Definition

DEVOPS

DevOps explained for UK software developers and business owners. DevOps is a set of practices, principles, and culture that combines software development (Dev) and IT operations (Ops) t... UK context, examples, and related services.

Read Definition

Microservices

Microservices explained for UK software developers and business owners. Microservices architecture is a software design approach where an application is built as a collection of small, indepen... UK context, examples, and related services.

Read Definition

Open Banking

Open Banking explained for UK software developers and business owners. Open Banking is the UK's implementation of PSD2 (Payment Services Directive 2) — a regulatory framework that requires th... UK context, examples, and related services.

Read Definition

Kubernetes

Kubernetes explained for UK software developers. Kubernetes (commonly abbreviated as K8s) is an open-source container orchestration platform that automates the deploymen... UK context and related services.

Read Definition

Get Expert Advice on Integration-testing

Speak with our UK software development experts about Integration-testing. Free consultation, transparent pricing, no obligation.