QA and software testing

System integration testing

Maintain data integrity and operational reliability by ensuring your integrated systems connect and communicate without friction.

Keep data flowing and operations running smoothly

Many modern applications rely on a complex ecosystem of interconnected technologies - microservices, third-party APIs, databases, and legacy systems. Testing components in isolation isn’t enough. To deliver reliable digital experiences, everything needs to works together as a cohesive, consistent whole.

System integration testing (SIT) ensures components communicate effectively, share data accurately, and perform as expected when integrated.

  • Catch interface issues

    Identify mismatches, misconfigurations, or failures in how components exchange data - before they impact functionality.

  • Eliminate data mismatches

    Verify that data flows correctly across all integrated systems, maintaining consistency and accuracy from source to destination.

  • Reduce deportment risk

    Uncover system-level issues early to minimise post-launch issues, ensure stability, and keep operations running smoothly.

Southern Housing

Supporting Southern Housing through multiple transformation programmes

Delivering integration and migration testing for Southern Housing’s major transformation projects, including the merger with Optivo.

Read case study

Our system integration testing services

We tailor our system integration testing approach to match your architecture, scale, and development stage - helping you uncover and resolve integration issues before they impact users.

Early-stage integration testing

Early-stage system integration testing helps identify issues as soon as individual components are ready, rather than waiting for the full system build.

We validate API connectivity, data flows, and component interactions early in the development life-cycle. This includes functional integration tests, automated regression testing, and careful validation of data mapping and transformations to ensure data integrity across modules.

To reflect real-world conditions, we use both synthetic and production-like datasets for testing. Our tests run within CI/CD-aligned environments to support continuous delivery. We also simulate failure scenarios and edge cases to verify system resilience and recovery capabilities, helping prevent issues before they impact users.

End-to-end integration testing

As systems become more complex, end-to-end integration testing verifies that complete business workflows function smoothly across multiple modules, platforms, and external systems. SIT testing at this stage simulates real user interactions to validate business processes, focusing on user experience, data consistency, and system performance.

We test critical business logic to identify errors and inconsistencies, and simulate realistic user scenarios to uncover functional issues and performance bottlenecks. Automated regression tests and security checks at the integration layer help maintain stability and compliance. Full defect traceability supports faster debugging and issue resolution, ensuring your integrated systems work reliably in production.

This phase is especially critical during cloud migrations, infrastructure upgrades, or multi-platform roll outs, where dependencies span across services, teams, and environments.

To find out more about our integration testing services, get in touch.

A flexible approach to SIT testing

Whether you’re leading a major transformation or refining complex systems, we tailor our approach to suit your needs.

We can work alongside your internal teams as embedded QA or take on full responsibility as an outsourced testing partner — whichever fits your project best. Our aim is to integrate seamlessly into your workflows, providing meaningful support from day one.

Whether you need full SIT testing coverage or just an extra layer of support, we bring the right tools, knowledge, and hands-on experience to help uncover issues early, validate data flows, and ensure systems work smoothly together - so you can move forward with confidence.

'Zoonou are able to devise a test approach that accommodates a lot of moving parts. They integrate with you and work quickly, understanding requirements to execute the right test strategy. They are dynamic and proactive offering flexibility and scalability even under tight deadlines.'

- Tom Fernandes, Associate Project Manager at The Prince's Trust

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Keep your data flowing and systems running smoothly - contact us for a chat about our integration testing services.

Get in touch