> For the complete documentation index, see [llms.txt](https://docs.serverlessapigateway.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.serverlessapigateway.com/glossary/m/mocking.md). # Mocking In testing, the practice of simulating the behavior of real modules to achieve a controlled test environment. Mocking is a testing technique where simulated objects or services replace real dependencies to create a controlled test environment. Mocks mimic the behavior of real components, returning predefined responses to specific inputs, which allows developers to test code in isolation without relying on external systems. In API development, mocking is used at several levels. API mocking involves creating a simulated API server that returns predefined responses, allowing frontend developers to build against an API before the backend is implemented. Mock servers can be generated automatically from API specifications like OpenAPI documents. Tools such as Postman, WireMock, and Mockoon are commonly used for this purpose. Mocking is valuable in API gateway testing. Teams can mock backend services to test gateway configurations -- such as routing rules, authentication logic, and rate limiting -- without deploying actual services. This enables faster development cycles and more reliable testing. In integration testing, mocking external APIs prevents tests from failing due to third-party service outages or rate limits. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.serverlessapigateway.com/glossary/m/mocking.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.