Interface Testing
Interface testing verifies that communication between software components, systems, or external services functions correctly and exchanges data as expected.
“A type of integration testing performed to determine whether components or systems pass data and control correctly to one another.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Interface Testing?
The focus is on validating requests, responses, protocols, error handling, and data formats across interfaces.
Communication: Systems should exchange information correctly.
Data validation: Input and output formats must match interface specifications.
Error handling: Interfaces should respond appropriately to failures.
Real World Example
An insurance claims platform is connecting a claim intake service, a policy validation service, and a payment approval service.
Each part can look correct in isolation while the handoff between parts still fails. Interface testing helps testers focus on the boundary where data, timing, and responsibility meet.
The tester checks payloads, error handling, retries, missing fields, and the order of service calls instead of only confirming that each screen appears.
The claims flow becomes more dependable because Interface testing exposes defects that only appear when real components collaborate.
Practice Questions
Question 1
Which statement BEST describes Interface testing in the context of ISTQB terminology?
Question 2
A tester needs to explain Interface testing to a non‑technical stakeholder. Which approach is MOST appropriate?
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