Open-Source Alternatives to Insomnia

Hoppscotch is an open-source API development ecosystem designed for building, testing, and debugging REST, GraphQL, and real-time APIs. It provides a unified platform that functions across web browsers, desktop applications, and command-line interfaces, allowing developers to manage the entire API lifecycle from a single environment. The platform distinguishes itself through a highly interactive, command-driven interface that utilizes a global spotlight palette and keyboard shortcuts to streamline complex workflows. It supports advanced request manipulation and validation by executing JavaScr

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

Insomnia is a cross-platform API development environment that integrates a request debugger, schema design tools, a mocking server, and a test automation framework. It provides a unified workspace for sending requests and analyzing responses across REST, GraphQL, gRPC, and WebSocket protocols. The platform enables the design and preview of API specifications through a visual editor and allows for the simulation of backend behavior using mocking tools. It supports organizing and synchronizing API collections via local storage, cloud synchronization, or Git. The suite includes a command-line i

Yaak is a cross-platform desktop client and command-line utility designed for developing, testing, and debugging API endpoints. It supports multi-protocol request execution for REST, GraphQL, and gRPC services, providing a unified environment for managing network interactions, authentication credentials, and automated testing workflows. The tool distinguishes itself through a local-first architecture that stores all workspace configurations and request definitions directly on the filesystem. This design enables native integration with version control systems like Git, allowing teams to track

Posting is a terminal-based HTTP request manager designed for developing, testing, and documenting API endpoints. It functions as a keyboard-driven interface that allows users to execute requests, manage collections, and inspect server responses directly within the command line environment. By storing request configurations as plain text files on the local filesystem, the tool ensures that API definitions remain compatible with standard version control systems. The project distinguishes itself by treating API collections as version-controlled assets, enabling users to migrate existing workflo

Altair is a graphical GraphQL API client, integrated development environment, and schema explorer. It functions as a debugging tool and collaboration platform for executing queries, mutations, and subscriptions against GraphQL servers. The project distinguishes itself by offering cloud-synced workspaces for organizing and sharing query collections among teams. It provides a flexible extensibility framework that allows the installation and execution of third-party plugins within isolated sandboxes. The platform covers a broad range of capabilities, including AI-assisted query writing, visual

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

Reqable is a cross-platform network debugging tool that functions as an HTTP/HTTPS debugging proxy, a REST API client, and a traffic replay tool. It captures, inspects, and modifies live traffic using a local MITM proxy engine, supports VPN tunnel capture for mobile devices, and provides a Python scripting sandbox for custom traffic processing. The application is available on Windows, macOS, Linux, iOS, and Android. The tool distinguishes itself by combining traffic interception with breakpoint-based request modification, allowing users to pause live HTTP traffic for manual inspection and alt

Insomnia is a desktop application designed for the design, testing, and debugging of network requests. It serves as a comprehensive environment for managing the API lifecycle, allowing users to draft interface specifications, simulate endpoints, and execute automated testing workflows within continuous integration pipelines. The platform distinguishes itself through a modular, plugin-based architecture that enables the integration of custom scripts and external tools. It supports complex development needs by providing a local-first data persistence model, environment-variable substitution for

Postcat is an integrated platform for API design and documentation, serving as a REST API client and a mock server. It provides a workspace to define technical requirements and data schemas, allowing development teams to align on interface behavior. The platform features a plugin architecture that enables the integration of third-party tools and custom capabilities. It decouples frontend and backend development cycles by generating simulated server responses based on predefined data structures. The toolset includes an environment management system for switching between development, staging,

Developer-first OpenSource API DevTool, Postman/Insomnia alternative.

graphql-request is a lightweight, type-safe GraphQL client library for JavaScript that runs across browsers, Node.js, and other JavaScript environments. It provides a minimal HTTP client for sending queries and mutations, with a promise-based execution model that uses the native fetch API for cross-runtime compatibility without additional dependencies. The client supports reusable selection set composition at runtime, allowing fragments to be shared across multiple requests to reduce duplication. It includes a plugin-based extension system for adding custom middleware, tracing, or file upload