Open-source alternatives to Bruno

Newman is a headless API client and command line tool for executing Postman collections. It serves as an API test automation tool and execution engine that allows users to run predefined sets of API requests without a graphical interface. The project differentiates itself as a data-driven testing engine, capable of iterating through request sequences using external JSON or CSV files to validate multiple sets of input values. It also functions as an API execution reporter, utilizing a plugin-based interface to output results in formats such as JSON and JUnit. The tool covers broad capability

Hurl is a command line HTTP testing tool and REST API test runner that uses a declarative, plain-text format to specify HTTP requests and responses. It functions as a client for continuous integration pipelines, allowing users to describe request sequences without a full programming language. The tool distinguishes itself by sequencing HTTP calls and verifying responses through matchers and variable capture. It maintains a stateful variable store, enabling data extracted from one response to influence subsequent requests within a workflow. The system covers API integration testing and REST w

Electric is a Postgres data synchronization engine and replication proxy designed to enable local-first software. It replicates data from Postgres databases to client-side stores in real time using logical replication, allowing applications to maintain a local embedded database for offline access and low-latency updates. The system distinguishes itself by using shapes to filter and authorize specific subsets of database rows and columns before streaming them to clients or edge workers. It further supports multi-user collaboration by integrating a conflict-free replicated data type framework t

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

This project is a version control documentation tool designed to automate the generation of release notes and changelogs. It functions as a pipeline-based engine that parses repository history, categorizes commits, and transforms them into structured documentation. By leveraging conventional commit patterns or custom regular expressions, it provides a consistent method for tracking project evolution and managing semantic versioning. What distinguishes this tool is its highly flexible template-driven architecture, which allows for deep customization of output formatting, grouping, and sorting.

This project is a terminal-based HTTP client designed for interacting with web services, debugging APIs, and automating network requests. It provides a specialized command-line interface that simplifies the construction of complex HTTP exchanges, allowing users to test and inspect web services directly from the shell. The tool distinguishes itself through a declarative syntax engine that translates shorthand command-line tokens into fully formed HTTP requests, including headers, parameters, and body payloads. It features a modular, plugin-based architecture that enables users to extend core f

Mise is a development environment orchestrator that manages software runtimes, environment variables, and task execution. It functions as a version manager and task runner, providing a unified interface to synchronize project-specific configurations and dependencies across different machines. By automating the installation and switching of tools, it ensures that development environments remain consistent and reproducible. The project distinguishes itself through a hierarchical configuration system that automatically discovers settings by traversing the directory tree. It uses shim-based comma

Epicenter is a local-first knowledge management system and data orchestrator designed to structure information generated by large language models into validated schemas. It functions as a storage architecture that persists application data in human-readable files and databases to ensure user ownership and portability. The system distinguishes itself by projecting language model outputs into structured, schema-validated tables and utilizing conflict-free replicated data types to synchronize application state across multiple devices without a central server. This allows for offline access and c

Swell is an API development and testing client designed for interacting with modern network protocols, executing GraphQL operations, and running local mock servers. It provides a unified interface for connecting to endpoints served over HTTP/2, WebSockets, Server-Sent Events, gRPC, tRPC, and WebRTC, enabling live messaging, monitoring, and debugging. The platform includes a concurrent load testing engine that spawns parallel worker threads to evaluate endpoint performance under heavy traffic, alongside a local mock server engine for simulating backend responses during frontend development. It

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

Casdoor is a centralized identity and access management platform that functions as an OAuth 2.0 authorization server. It provides a comprehensive suite of services for managing user identities, authentication sessions, and access policies across both web and machine-to-machine applications. Built with a decoupled frontend-backend architecture in Go, the platform supports high-concurrency environments and offers a web-based management interface for administrative tasks. The platform distinguishes itself through its extensive support for federated identity management, allowing integration with

The Google Workspace CLI is a command-line interface and Google API client designed to automate tasks across Google Workspace services. It functions as a cloud productivity automator that uses the Google Discovery Service to dynamically generate command structures and parameter requirements at runtime. The project distinguishes itself by providing a specialized AI agent toolset, exposing a server over standard input and output to provide structured tool definitions and skills for AI clients. It includes security layers for AI content sanitization to protect against prompt injection and utiliz

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

This library is a PHP toolkit for managing OAuth 2.0 authentication flows and connecting applications to external service providers. It provides a standardized framework for handling token exchanges, managing authorization grants, and retrieving user profile information from diverse identity platforms. The project is distinguished by its inheritance-based provider pattern, which allows developers to build custom integration clients by extending base logic to support unique service workflows and non-standard API specifications. It employs interface-driven contracts to ensure consistent behavio

Dokploy is a self-hosted platform-as-a-service designed to simplify the deployment and management of containerized applications and databases. It provides a centralized control plane that decouples administrative management from application workloads, allowing users to oversee infrastructure across multiple server nodes through a unified web interface or a command-line tool. The platform distinguishes itself through an extensive library of pre-configured application templates, enabling the rapid deployment of databases, identity providers, and various productivity or development tools. It sup

Swagger UI is an OpenAPI specification renderer and documentation interface that transforms JSON or YAML API definitions into a navigable, searchable website. It functions as an OpenAPI documentation UI and request client, providing a visual catalog for exploring endpoints and sending live HTTP requests to a server using a schema-defined interface. The project distinguishes itself through a plugin-based extension system and a schema-driven UI generation model. This architecture allows for the injection of custom components, state selectors, and helper functions to modify core behavior and lay

Karate is a Gherkin API testing framework and JVM test orchestrator designed for API validation, workflow automation, and browser automation. It provides a unified environment for executing scriptable logic on the Java Virtual Machine with thread-safe concurrent processing. The project includes a built-in HTTP mock server to simulate backend API behavior by delivering dynamic responses to intercepted requests. It also features a visual regression testing tool that detects interface changes by comparing screenshots against baseline images using pixel-matching analysis. The system supports API

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,

Django REST Framework is a toolkit for building standards-compliant web services that map complex data models to structured HTTP responses. It provides a modular architecture for handling the request lifecycle, including authentication, permission checks, and content negotiation. The framework is designed to facilitate the development of robust APIs by transforming complex data types into native formats and validating incoming request payloads against defined schemas. The project distinguishes itself through a highly modular, class-based design that allows developers to build complex views an

NATS Server is a high-performance, lightweight messaging system designed for cloud-native applications, edge computing, and distributed microservices. It functions as a distributed publish-subscribe broker that routes messages using hierarchical, dot-separated subject strings, enabling decoupled communication between services without requiring centralized broker lookups. The system supports core messaging patterns including asynchronous publish-subscribe, request-reply, and load-balanced queue processing. The platform distinguishes itself through a decentralized architecture that eliminates t

RestSharp is a .NET HTTP client library designed for interacting with RESTful web services. It provides a high-level request wrapper and a dedicated REST API client to manage endpoints, headers, and query parameters. The library includes a serialization mechanism that automatically converts objects to and from JSON or XML formats for API payloads. It also features a system for managing API credentials and security tokens to ensure authorized access to protected remote resources. The toolkit covers broad capabilities for external web service integration, including generic type-based deseriali

The OpenAPI Specification is a formal, vendor-neutral standard for defining the structure, endpoints, and data models of HTTP-based web services. By providing a machine-readable interface definition language, it enables developers to establish clear API contracts that ensure consistency across diverse programming languages and backend systems. This specification promotes a design-first development approach, where interface behavior is defined through static, declarative configuration files rather than imperative code. This structure allows for the automated generation of type-safe client libr

apollo-ios is a GraphQL client library for iOS and Apple platforms that enables type-safe network communication. It transforms GraphQL operations into generated Swift models, ensuring that network responses are validated at compile time to eliminate manual mapping. The library features a normalized cache manager that stores entities in a flat structure to maintain data consistency across different application views. It also optimizes network performance using hash-based persisted queries to reduce payload sizes and supports real-time data streaming via WebSockets or HTTP subscriptions. The p

GraphQL Editor is a collaborative workspace platform for designing, editing, and managing GraphQL schemas. It provides an interactive graph-based visual editor that lets teams create and explore schemas without writing code, alongside a full-featured Monaco text IDE with real-time syntax validation. The platform supports AI-powered schema generation from natural language prompts, federated schema composition that visualizes type merging across subgraphs, and AST-level schema comparison that highlights structural differences between versions. The platform distinguishes itself through its bidir

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

Flox is a Nix environment manager designed to create, share, and maintain reproducible software stacks. It uses declarative manifests to isolate project dependencies and toolchains, ensuring identical runtimes across different machines and operating systems. The platform distinguishes itself by enabling the deployment of imageless workloads to Kubernetes, allowing software to run in pods without traditional container images. It can also synthesize OCI-compliant container images and distroless artifacts directly from declarative environment definitions. The project covers broad capability are