Superagent is an isomorphic JavaScript HTTP client for sending network requests and processing responses across both Node.js and web browser environments. It provides a fluent request builder that uses a chainable interface to construct complex network requests with custom headers, query strings, and bodies.
The library functions as a runtime-agnostic request adapter, allowing a single codebase to work consistently across different environments. It includes specialized capabilities such as an HTTP/2 client for forcing the HTTP/2 protocol and a Node.js agent for managing Unix socket connections and TLS settings.
Its capability surface covers API integration and data consumption, including multipart file uploads, automatic response deserialization, and stream-based data piping. It also provides security and session management through persistent cookie state, request authentication, and TLS connection configuration.
The system is extensible via a client plugin system and plugin-based lifecycle hooks that allow for custom behavior during the request cycle.
