> 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/c/client.md). # Client A client is any software application, device, or system that sends requests to a server to access resources or services. In web development, the most common client is a web browser, but clients also include mobile applications, desktop applications, command-line tools, and other servers making API calls. The client-server model is foundational to how the internet and APIs work. Clients initiate communication by sending requests (typically over HTTP or HTTPS), and servers respond with the requested data or confirmation of an action. This separation of concerns allows clients and servers to evolve independently as long as they adhere to the agreed-upon API contract. In API management, understanding client behavior is important for setting appropriate rate limits, designing authentication flows, and optimizing response formats. API gateways can identify and differentiate clients based on API keys, OAuth tokens, or IP addresses, and apply client-specific policies such as throttling, usage quotas, or access restrictions. --- # 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 dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.serverlessapigateway.com/glossary/c/client.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.