REST Client

Enables developers to write HTTP requests directly in `.http` and `.rest` files using a plain-text syntax with `###` delimiters separating multiple requests. Each request is parsed by the extension's lexer, validated against HTTP RFC 2616, and executed within the VS Code process without leaving the editor. The extension renders responses in a split-pane view with syntax highlighting for JSON, XML, and other content types, eliminating the need for external HTTP clients like Postman or curl.

Implements a hierarchical variable resolution system supporting environment variables, file-level variables, request-level variables, and prompt variables. The extension provides 8 built-in dynamic variable types ({{$guid}}, {{$timestamp}}, {{$randomInt}}, {{$datetime}}, {{$localDatetime}}, {{$processEnv}}, {{$dotenv}}, {{$aadToken}}) that generate values at request time. Variables are substituted into URLs, headers, and request bodies using mustache-style syntax ({{variableName}}), with auto-completion, hover documentation, and diagnostic validation integrated into the editor.

Automatically captures and stores cookies from HTTP responses (Set-Cookie headers) and includes them in subsequent requests (Cookie header). The extension maintains a cookie jar per host/domain, respecting cookie attributes like Path, Domain, Expires, and HttpOnly. Developers can view, edit, and clear cookies manually. This enables testing stateful APIs that rely on session cookies without manual cookie extraction and header manipulation.

Allows developers to configure HTTP and HTTPS proxies for request routing, enabling testing through corporate proxies, VPNs, or traffic inspection tools. Proxy settings are configured in VS Code settings and applied to all requests. The extension supports proxy authentication (Basic Auth) and proxy bypass rules for specific hosts. This enables developers behind corporate firewalls to test external APIs without manual proxy configuration per request.

Generates executable code snippets in Python, JavaScript, and other languages from composed HTTP requests. The extension analyzes the request (method, URL, headers, body, authentication) and generates equivalent code using popular HTTP libraries (requests for Python, fetch for JavaScript, etc.). Generated snippets include proper error handling, header construction, and authentication setup. This enables developers to quickly convert REST Client requests into production code without manual translation.

Provides syntax highlighting for HTTP request syntax (methods, headers, URLs, request bodies) and response content (JSON, XML, HTML, plain text). The extension integrates CodeLens actionable links directly in the editor, displaying 'Send Request' links above each request block that developers can click to execute. Syntax highlighting extends to comments, variable references, and request delimiters (###). Auto-completion suggests HTTP methods, headers, MIME types, and variable names as developers type.

Provides VS Code symbol navigation (Ctrl+Shift+O) to jump to request definitions and file-level variable declarations within `.http` files. Developers can use 'Go to Definition' to navigate to variable definitions and 'Find All References' to locate all usages of file-level variables. This enables quick navigation in large request files with many requests and variables, improving code organization and refactoring.

Supports 6 authentication mechanisms: Basic Auth (base64-encoded credentials in Authorization header), Digest Auth (RFC 2617 challenge-response), SSL Client Certificates (file-based), Azure Active Directory (interactive browser-based token flow with cloud environment selection), Microsoft Identity Platform (tenant-aware token generation), and AWS Signature v4 (request signing). Azure AD tokens are generated via {{$aadToken}} variable with parameters for cloud environment (public, cn, de, us, ppe), tenant ID, and audience specification, with token caching behavior unknown.

Renders HTTP responses in a split-pane view with syntax highlighting for JSON, XML, HTML, and plain text. The extension supports multiple preview modes: headers only, body only, full response, and combined request+response view. Image responses are rendered as inline images rather than raw binary. Responses can be folded/unfolded for readability, and the preview font (size, family, weight) is customizable. Raw response bodies can be saved to disk, and response history is auto-saved for later retrieval.

Enables sequential request execution where responses from one request can be captured and used as variables in subsequent requests. The extension maintains request history and allows variables to reference previous response values, enabling workflows like: authenticate (request 1) → extract token from response → use token in API call (request 2). Variable substitution occurs at request time, allowing dynamic request composition based on prior responses. The exact mechanism for response-to-variable extraction (e.g., JSONPath, regex) is undocumented.

Supports GraphQL query syntax within `.http` and `.rest` files, enabling developers to compose GraphQL queries and mutations with variables. The extension parses GraphQL syntax, provides syntax highlighting, and executes queries against GraphQL endpoints via HTTP POST requests. GraphQL variables are defined in the request body or via the extension's variable system, allowing parameterization of queries without manual string manipulation.

Parses cURL commands and converts them into REST Client request syntax, enabling developers to import existing curl commands from documentation or terminal history. The extension also generates cURL commands from composed requests, allowing export for use in scripts or documentation. This bidirectional conversion supports all cURL options relevant to HTTP requests (headers, authentication, body, method, etc.) and integrates with the extension's variable system.

Supports SOAP request composition with XML envelope building snippets and syntax highlighting. Developers can compose SOAP requests with headers, body elements, and namespaces directly in `.http` files. The extension handles SOAP-specific headers (SOAPAction, Content-Type: application/soap+xml) and provides templates for common SOAP patterns. Responses are parsed and rendered with XML syntax highlighting.

Implements environment management where developers define multiple named environments (dev, staging, production) in VS Code settings with environment-specific variables. The extension allows switching between environments, and all variable substitutions use the currently active environment's values. Environments can share common variables via a 'shared' environment, and environment-specific variables override shared variables. This enables testing the same request against different backends without modifying the request file.

Automatically saves all executed requests and responses to a local history store, allowing developers to view, search, and re-execute past requests. History is persisted across VS Code sessions and can be cleared manually. The extension displays request history in a sidebar or command palette, enabling quick access to frequently used requests without re-typing. History entries include request method, URL, timestamp, and response status code.