Open-source alternatives to RestSharp

Hyper is a low-level networking library designed for building high-performance HTTP clients and servers. It provides a foundational toolkit for creating network services that leverage asynchronous execution and memory-safe data handling, supporting both HTTP/1 and HTTP/2 protocols. The library distinguishes itself through a protocol-agnostic architecture that separates transport logic from HTTP semantics. It utilizes a service-trait abstraction to decouple network logic from the underlying transport, enabling developers to inject custom middleware for request interception and response transfo

Resty is a high-level HTTP client library for Go designed for consuming REST services. It provides a streamlined interface for executing network requests, managing server-sent event streams, and automatically mapping JSON and XML responses into data structures. The library includes built-in mechanisms for service resilience and traffic management, such as circuit breakers to prevent cascading failures, token-bucket rate limiting, and automated request retries with exponential backoff. It also features client-side load balancing to distribute outgoing traffic across multiple base URLs and requ

This is a Ruby HTTP client designed for REST API integration, resource modeling, and automated network communication. It provides a set of tools for managing headers, cookies, and SSL configurations, along with a dedicated command-line interface for executing one-off HTTP commands and managing interactive API testing sessions. The project differentiates itself through its resource modeling capabilities, which allow for the definition of persistent base URLs and credentials to construct nested subresource endpoints. It also features a multipart request handler that detects MIME types to upload

Moya is a network abstraction layer for Swift that provides a structured framework for defining and executing REST API requests. It functions as a type-safe API client that decouples network endpoint definitions from the underlying implementation details to prevent configuration errors and URL typos. The project distinguishes itself by using protocol-based endpoint definitions and a provider-coordinated execution model. It includes a system for mapping network responses to strongly typed objects and features a dedicated tool for generating type-safe network interface files from external REST

r2 is a JavaScript HTTP client library and asynchronous request library used for executing network calls. It provides a runtime-agnostic network layer that abstracts underlying HTTP implementations to ensure consistent behavior across different JavaScript execution environments. The library functions as a JSON API client, automatically parsing response bodies and formatting outgoing payloads. It utilizes a promise-based interface to manage the lifecycle of HTTP requests and responses. The project covers REST API integration and HTTP header management, allowing users to attach custom key-valu

Automatisch is an open-source, self-hosted automation platform designed to orchestrate multi-stage workflows across various third-party web services. It functions as a no-code integration engine that allows users to connect disparate applications, enabling the automated movement of data and the execution of tasks without manual intervention. By running the platform on private infrastructure, users maintain full control over their data and ensure compliance with internal security policies. The platform distinguishes itself through a focus on secure, local credential management and flexible int

Rest-assured is a Java-based REST API testing framework and HTTP client library designed for automating web service tests. It provides a fluent domain-specific language and assertion library to send HTTP requests and validate response metadata, including status codes, headers, cookies, and bodies. The framework is distinguished by a method-chaining DSL that creates readable specifications for API interactions. It features a filter-based request interception pipeline, object-mapping serialization for converting Java objects to JSON or XML, and a path-based parsing system to isolate specific fi

Jackson is a Java data binding framework and multi-format data serializer used to translate data structures into native language objects. It functions as a JSON data binding library and a streaming parser that reads and writes data as discrete tokens to process large datasets with minimal memory. The project distinguishes itself through a bytecode serialization accelerator that replaces standard reflection with generated bytecode to increase data binding speed. It employs a module-based extensibility model to support a wide range of formats beyond JSON, including XML, YAML, CSV, TOML, and bin

Moshi is a JSON serialization library and parser for Kotlin and Java. It functions as a reflectionless JSON encoder that converts typed objects to JSON strings and parses JSON data back into language objects. The library distinguishes itself through compile-time adapter generation, which removes the performance overhead associated with runtime reflection. It also provides a polymorphic JSON mapper that uses type identifiers to resolve and instantiate specific subclasses of a common base type. The framework supports custom adapter definitions for specialized type conversion, including nullabi

Restangular is a REST client and resource mapper for AngularJS applications. It provides a suite of tools for mapping API endpoints to local objects and collections, facilitating frontend CRUD implementation through standard HTTP methods. The project distinguishes itself through an async data binding system that links user interface elements to server-side objects, ensuring automatic updates upon request completion. It also features a programmable request interceptor pipeline for modifying headers and transforming responses, as well as a JSONP request handler to bypass same-origin policy rest

ObjectMapper is a JSON serialization framework for Swift that maps JSON strings and dictionaries into strongly typed classes and structs. It functions as a data mapper and converter, facilitating the bidirectional transformation of data between raw JSON and Swift model objects. The library uses protocol-based mapping to associate specific JSON keys with object properties. It supports nested key extraction via dot-notation pathing and employs custom transformation classes to bridge the gap between JSON and Swift types. The framework provides capabilities for model validation during initializa

This project is a high-performance JSON library for Go, serving as a replacement for the standard encoding/json package. It provides a serialization engine for encoding and decoding data structures, alongside a schemaless parser for extracting specific values from JSON blobs using paths. The library distinguishes itself through a focus on reducing CPU and memory overhead. It implements a high-performance encoder that utilizes buffer reuse and reduced float precision to increase data throughput. Broad capability areas include data serialization, high-performance JSON processing, and schema-le

This is a desktop HTTP client application used for constructing, sending, and analyzing HTTP and GraphQL requests. It provides a graphical interface for API development and testing, including a dedicated GraphQL client with schema-driven autocomplete and validation. The project features an integrated AI assistant that generates API requests from natural language prompts. It supports a complex organization system of spaces and collections with hierarchical authentication inheritance and recursive variable resolution for dynamic request values. The tool covers a broad range of capabilities, in

Lark CLI is a terminal-based tool designed for automating tasks and managing resources across the Lark and Feishu productivity ecosystem. It functions as a cloud workspace automator and REST API client, providing a command line interface to programmatically manage organizational documents, calendars, emails, and tasks. The project distinguishes itself through an AI agent skill framework that allows for the integration and deployment of both bundled and custom skills. It features an identity-aware execution context that enables switching between user and bot identities, and employs a sidecar-b

Flurl is a .NET fluent URL builder and HTTP client wrapper designed for constructing complex web addresses and sending requests with a chainable interface. It functions as a URL manipulation library and an HTTP mocking framework to facilitate network interaction and testing. The project distinguishes itself through a fluent interface that allows for the incremental construction of paths, query parameters, and fragments. It provides a dedicated mocking system to intercept outgoing network traffic and return predefined responses, enabling isolated unit testing without a live server. Its broade

Axios is a promise-based HTTP client used to make asynchronous network requests in both browser and Node.js environments. It functions as a multi-environment network adapter that abstracts the transport layer to ensure consistent behavior across different runtimes. The project distinguishes itself through a request lifecycle management system that allows for the cancellation of active requests, the setting of timeouts, and the monitoring of upload and download transfer progress. It includes a mechanism for intercepting network traffic, enabling the transformation of outgoing requests and inco

Fuel is a Kotlin HTTP client library for Android and Kotlin applications that handles both synchronous and asynchronous web requests. It functions as a network wrapper that supports executing calls via suspending functions in coroutines, reactive streams, and traditional callbacks. The library features built-in integration for Android LiveData to bind network responses directly to observable state holders for user interface updates. It also includes a JSON serialization client that utilizes customizable mappers to convert raw HTTP response bodies into structured data objects. Capability area

Crow is a minimalist C++ micro web framework designed for building fast web servers and REST APIs. It provides a lightweight toolkit for web development in C++, offering core routing and request handling capabilities. The framework includes a built-in JSON parser for converting strings into structured data and an HTML template engine for generating dynamic web pages on the server. It also functions as a WebSocket server library to enable bidirectional, real-time communication between servers and web clients. Additional capabilities include a middleware-based request pipeline for executing sh

Got is a promise-based HTTP request library for Node.js that supports HTTP/2 and streaming. It provides a system for making network requests with a focus on asynchronous control flow and type-safe API client development. The library is distinguished by its middleware-based request lifecycle, which uses interceptors and plugins to modify request options and response data. It includes a configurable automatic retry mechanism with backoff strategies, a built-in HTTP response cache, and a cookie-jar system for maintaining persistent sessions. Broad capabilities cover data handling through duplex

Faraday is an HTTP client library for Ruby that sends requests and processes responses through a middleware pipeline with pluggable adapters. Its core identity is built around a middleware-pipeline architecture where HTTP requests and responses flow through a chain of components that can modify, log, or transform data before reaching the backend, combined with an adapter-based backend abstraction that delegates HTTP execution to interchangeable backends like Net::HTTP or Typhoeus. The library distinguishes itself through a parallel-execution engine that dispatches multiple HTTP requests concu

This project is a framework for the efficient serialization and deserialization of data structures. It provides a unified, macro-based interface that automates the conversion of complex internal objects into standardized formats and reconstructs them from raw input streams or buffers. By leveraging compile-time code generation, the library minimizes manual implementation overhead while ensuring consistent logic across diverse data types. The framework distinguishes itself through a format-agnostic data model and a visitor-based parsing architecture that decouples data structures from specific

This project is a comprehensive sample library and implementation guide for ASP.NET Core. It provides a collection of practical examples and projects that demonstrate how to build web applications, RESTful APIs, and high-performance services. The repository focuses on a variety of architectural patterns, including the development of Minimal APIs, contract-first gRPC services, and real-time communication using WebSockets and Server-Sent Events. It includes detailed implementations for user identity and security, such as token-based authentication and CSRF protection. The codebase covers a bro

This project is a programmatic client for managing the lifecycle of documents within a distributed JSON search engine. It provides an Elasticsearch search client for indexing documents and performing complex queries, alongside a low-level client that acts as a flexible wrapper for sending raw HTTP requests to a cluster. The client features a fluent request builder that maps typed requests to REST API endpoints and a generic mapping layer to transform JSON responses into strongly typed objects. It employs a pluggable serialization mechanism to decouple the request-response lifecycle from speci

Guzzle is a PHP HTTP client used for sending synchronous and asynchronous requests to web services. It serves as a concurrent HTTP request manager, an HTTP stream handler, and a middleware-based HTTP pipeline. The project is a PSR-7 compliant client, utilizing standardized PHP interfaces for requests, responses, and streams. The library differentiates itself through a customizable functional handler stack that allows for the interception and modification of the request and response lifecycle. It features an adapter-based transport system that enables swapping between network implementations,

Bruno is a local-first API client designed for building, testing, and managing network requests across a wide range of protocols. By storing all collections and configurations as plain-text files directly on the local filesystem, it enables native version control and offline access, ensuring that project data remains under user control without requiring cloud synchronization. The platform distinguishes itself through a declarative approach to API management, utilizing a domain-specific language to define request parameters and metadata. This architecture supports a robust testing environment

Feign is a declarative Java HTTP client framework that maps method signatures to REST API requests. It functions as an HTTP interface mapper, allowing the creation of type-safe clients by defining service interfaces with annotations to eliminate manual request logic. The framework features a pluggable HTTP transport layer, which decouples request definition from execution by routing network traffic through interchangeable underlying HTTP engines. It provides a comprehensive request management pipeline including interceptors for modifying headers, policy-driven retry logic for failure recover