In the dynamic world of software development, Application Programming Interfaces (APIs) are the vital conduits connecting disparate services, applications, and data sources. They are the engines of modern digital experiences. Consequently, the tools used to design, develop, debug, test, and manage these APIs are fundamental to developer productivity and application quality. For many years, Postman established itself as a dominant player in this space, offering a comprehensive suite of features for interacting with APIs. Insomnia also gained significant traction as a popular, user-friendly alternative.
However, the API client landscape is undergoing a significant shift. Recent changes in the business models and feature strategies of established players, particularly around mandatory cloud synchronization, account requirements, pricing tiers, and data privacy concerns, have led many developers and organizations to actively seek Postman alternatives and Insomnia alternatives. Community discussions (like this one on Reddit) highlight a growing desire for tools that prioritize user control, data privacy, offline access, and freedom from vendor lock-in. Concerns about feature bloat in established tools also drive searches for simpler, more focused solutions.
The fantastic news is that the developer community, particularly the open-source ecosystem, has risen to the challenge. There is now a vibrant and diverse range of high-quality, free Postman alternatives that offer powerful features, flexible workflows, and greater control over your data and development environment. Whether you need a lightweight alternative, a feature-rich desktop application, a seamless VS Code extension, a powerful CLI tool, or a dedicated API testing framework, there's likely an open-source solution that fits your needs.
This document serves as a curated list of Awesome API Clients, focusing specifically on Open Source and Free Postman Alternatives. These tools empower developers with the functionality they need for effective API development and testing without the compromises often associated with proprietary, cloud-centric platforms.
The migration towards open-source API clients isn't merely about avoiding costs; it's often rooted in core principles crucial to developers and modern software practices:
- Data Privacy & Control (No Forced Cloud Sync): Mandatory cloud features in tools like Postman and recent versions of Insomnia raise significant concerns about the storage location of sensitive API keys, tokens, environment variables, and request history. Open-source alternatives, especially those offering offline-first capabilities (like Bruno, Restfox) or self-hosted options (like Yaade), provide absolute control, ensuring sensitive data remains entirely within your local machine or trusted infrastructure. This is a paramount concern for many individuals and organizations.
- Avoiding Vendor Lock-in: Relying exclusively on a proprietary platform can create dependencies that make future transitions difficult or expensive. Open-source tools often utilize standard, text-based formats for storing collections and environments (e.g., JSON, YAML, or custom formats easily managed with Git like Bruno's Bru Lang), ensuring data portability and preventing lock-in.
- Cost-Effectiveness: While Postman and others offer free tiers, accessing advanced features, enabling collaboration for larger teams, or exceeding usage limits often necessitates paid subscriptions. Many free open-source alternatives provide a comparable, if not superior, feature set without any mandatory costs, democratizing access to powerful API tooling.
- Flexibility, Extensibility & Customization: Open-source software can often be inspected, modified, and extended more easily than closed-source counterparts. Some tools (like Milkman) have explicit plugin architectures, while others can be integrated into bespoke workflows through scripting or leveraging their source code.
- True Offline Access: Mandatory sign-in and cloud dependency hinder work in environments with restricted or no internet access. Many alternatives listed here are designed to work perfectly offline, ensuring productivity regardless of connectivity.
- Simplicity & Focus (Avoiding Feature Bloat): Some developers feel that established tools have become overly complex ("feature bloat"). Many alternatives focus on providing a clean, streamlined experience centered on core API interaction and testing tasks. Lightweight alternatives are actively sought after.
- Community & Transparency: Open-source projects thrive on community contributions, bug reports, and feature suggestions. Development is transparent, and users can audit the code for security or functionality verification. This collaborative model fosters trust and innovation.
This list prioritizes active, community-supported, and genuinely open-source projects relevant for API development and testing:
- Open Source: The project must possess a publicly accessible source code repository under a recognized open-source license (MIT, Apache 2.0, etc.).
- Free Core Functionality: The essential features for sending API requests (REST, possibly GraphQL/gRPC), managing environments, and organizing requests (collections) must be available for free, without requiring a paid subscription for typical Postman/Insomnia use cases.
- Active/Viable: Generally, projects should exhibit signs of life, such as having more than 200 stars on their primary repository and contributions from at least 2 individuals. This indicates a baseline level of community interest and sustainability. (Exceptions may be made for highly relevant niche tools or established projects like
curl).
This list is categorized for clarity: Web-Based, Desktop, IDE Integration, Command-Line (CLI), and Automated API Testing Frameworks. While some tools might fit into multiple categories (e.g., Requestly), they are listed under their primary or most prominent form.
Defining a single "best" Postman alternative is challenging, as the ideal tool heavily depends on individual or team priorities. Needs vary significantly – some prioritize absolute simplicity and offline use, others require extensive collaboration features, while many are driven by the core principles of open-source development outlined previously.
However, when discussing modern, comprehensive alternatives that aim to match or exceed Postman's feature scope in a contemporary package, APIDog frequently emerges in discussions.
APIDog positions itself as an integrated API collaboration platform, covering the entire API lifecycle: design, development, debugging, testing, and documentation. Its key strengths often highlighted include:
- All-in-One Platform: It aims to consolidate tools, offering features often spread across multiple applications (design, mock servers, testing, documentation generation).
- User Experience: It generally receives praise for a modern, clean, and intuitive user interface.
- Collaboration Focus: Designed with team workflows in mind, offering features to facilitate shared API development and testing.
- Comprehensive Feature Set: Supports REST, GraphQL, WebSocket, gRPC, and Socket.IO, along with visual API design, automated testing, and CI/CD integration capabilities.
Accessible from any modern browser, these clients eliminate installation hassles and often facilitate easier sharing and collaboration. Many leverage browser storage for offline use or offer PWA (Progressive Web App) capabilities.
- Keywords: Offline-first, Web HTTP client, Lightweight alternative, Free Postman alternative.
- Description: Restfox directly tackles the cloud-sync concern by being an offline-first web client. Your workspaces, requests, and collections are stored locally in your browser's IndexedDB. It provides a clean, fast, and intuitive interface for making HTTP(S) requests, organizing them, managing environments, and scripting. It's designed to be simple yet powerful, offering core functionality without unnecessary complexity. Its emphasis on local storage and speed makes it an excellent free Postman alternative for those prioritizing privacy and performance in a web-based tool.
- Keywords: Open source API development ecosystem, REST, GraphQL, WebSocket, PWA, Free Postman alternative, Insomnia alternative, Browser-based.
- Description: Frequently cited as a top Postman alternative and Insomnia alternative, Hoppscotch (formerly Postwoman) is a feature-rich open-source API development ecosystem. Its sleek web interface supports REST, GraphQL, WebSocket, and Server-Sent Events. Key features include collections, environment variables, pre-request scripts, test scripts (JavaScript sandbox), documentation generation, and collaboration workspaces. It offers flexibility with data storage: local browser storage, optional Hoppscotch cloud sync, or even self-hosting. Its PWA support allows for an installable, near-native experience with offline access. Its comprehensive feature set makes it suitable for both individual developers and teams looking for a powerful, free, browser-based client.
- Keywords: Multi-protocol, GraphQL, WebSocket, Socket.IO, VS Code DX, Open Source Postman Alternative.
- Description: Firecamp aims to provide a superior Developer Experience (DX) inspired by VS Code. It stands out with its multi-protocol support, handling REST, GraphQL, WebSocket, and Socket.IO APIs within a unified interface. This makes it incredibly versatile for projects involving real-time communication alongside traditional APIs. Features include workspaces, collections, scripting, and a focus on collaborative workflows. Its VS Code-like command palette and layout offer familiarity for many developers. Firecamp is a strong open-source Postman alternative for those needing broad protocol support and appreciating a developer-centric UI.
- Keywords: gRPC, Web UI, Interactive, API exploration.
- Description: While not a general HTTP client, gRPC UI is an indispensable open-source tool for developers working with gRPC. It provides an interactive web UI for exploring and invoking gRPC services, much like Postman does for REST. Using gRPC reflection or compiled
.protofiles, it discovers services and methods, allowing users to easily craft requests (including metadata), view responses, and understand gRPC schemas directly in the browser. It significantly simplifies gRPC debugging and interaction compared to using purely CLI tools.
- Keywords: Self-hosted, Collaborative API development, Open-source, Privacy.
- Description: Yaade differentiates itself by being an open-source, self-hosted, collaborative API development environment. This focus on self-hosting is ideal for teams and organizations prioritizing maximum privacy and data control, ensuring all API definitions, collections, and secrets remain within their own infrastructure. It provides the essential features for managing requests, collections, and environments, facilitating teamwork in a secure, private setting. Yaade is a compelling choice for those who need collaborative features but want to avoid third-party cloud services entirely.
- Keywords: Text-based, In-browser HTTP client, Interface-less, Lightweight alternative.
- Description: Prestige offers a unique, text-based approach within the browser. It acts as an "interface-less" Postman alternative, appealing to developers who prefer defining requests using simple text rather than GUI fields. You write the method, URL, headers, and body directly in a text area, and Prestige executes the request, displaying the response. This minimalist, keyboard-centric workflow can be very efficient and makes sharing request definitions as simple as copying text. It's a lightweight alternative for those who value simplicity and text-based interaction.
- Keywords: Browser extension, API Client, API Mocking, Modify HTTP requests, Intercept.
- Description: Requestly is a versatile tool available as both a browser extension and a desktop app. Its origins lie in intercepting and modifying HTTP requests (e.g., redirecting URLs, modifying headers/responses, simulating network conditions), which is invaluable for frontend development and debugging. It has expanded to include a capable API client, allowing users to send HTTP(S) requests directly. It also features API mocking. This combination of interception, modification, mocking, and request sending in one tool makes it powerful, especially for web developers needing deep browser integration or comprehensive debugging capabilities. Its free tier offers significant functionality.
- Keywords: OpenAPI, Swagger, API Documentation, Interactive Testing, Open Source.
- Description: While Swagger UI's primary purpose is to render OpenAPI (formerly Swagger) specifications as interactive API documentation, it serves as a valuable tool for interactive testing. It generates a user interface directly from an API definition, allowing developers (and consumers) to explore endpoints, understand request/response models, and execute live API calls directly within the documentation page. It's open-source and widely used. Though not a full-fledged API client like Postman (lacking collections management, complex scripting, etc.), its ability to provide an immediate, interactive testing environment based on the API contract makes it an essential part of the API ecosystem and a useful tool for quick checks. Often discussed in "Swagger vs. Postman" comparisons, they serve different primary roles but overlap in interactive testing.
Installed natively on your OS (Windows, macOS, Linux), desktop clients often provide superior performance, deeper system integration, and guaranteed offline operation.
- Keywords: Opensource IDE for APIs, Offline-first, Git-friendly, Local storage, Privacy, Free Postman alternative, Insomnia alternative, Bruno.
- Description: Bruno has rapidly emerged as a leading free Postman alternative and Insomnia alternative, heavily praised in community discussions (Reddit, Hacker News). Its core philosophy is offline-first operation and storing API collections directly on the local filesystem using Bru Lang, a plain text markup language. This makes collections inherently Git-friendly, allowing seamless version control alongside code. Bruno offers a clean UI, REST and GraphQL support, environment variables, declarative scripting (JavaScript), and assertions for API testing. Its explicit rejection of mandatory cloud sync strongly appeals to users prioritizing privacy and local storage. Many see Bruno as a modern, fast, and developer-centric offline alternative.
- Keywords: Intuitive desktop API client, Lightweight alternative, Cross-platform.
- Description: Yaak focuses on being the "most intuitive" desktop API client, prioritizing simplicity and ease of use. It provides a clean, polished interface for sending requests, managing environments, and organizing collections across different workspaces. It aims to be a lightweight alternative that is quick to learn and efficient for daily API interaction tasks, available for Windows, macOS, and Linux.
- Keywords: Cross-platform API Client, Flutter, Open-source, Beautiful UI.
- Description: Built with Flutter, API Dash delivers a beautiful and consistent user experience across Windows, macOS, and Linux. It provides the core functionalities needed for interacting with REST APIs, including request creation, response inspection, collections, and environment management. Its focus on a visually appealing UI and native cross-platform performance makes it an attractive open-source option.
- Keywords: gRPC GUI client, gRPC-Web, Desktop client.
- Description: Similar to gRPC UI for the web, ezy is a dedicated desktop GUI client specifically for gRPC and gRPC-Web services. It simplifies interaction with gRPC endpoints compared to CLI tools, offering features like service discovery (reflection or proto files), request crafting, response viewing, and metadata handling in a user-friendly desktop application. An essential tool for developers heavily invested in the gRPC ecosystem.
- Keywords: gRPC GUI Client (Unmaintained).
- Description: BloomRPC was an early and popular GUI client for gRPC services, known for its clean interface based on proto file definitions. (Important Note: BloomRPC appears to be unmaintained). While historically significant, users should consider more actively maintained alternatives like ezy or Evans CLI for ongoing projects. It's listed here for context due to its previous popularity.
- Keywords: Extensible Request/Response Workbench, Plugin architecture, JavaFX.
- Description: Milkman bills itself as an extensible request/response workbench. Built using JavaFX, its key feature is a plugin-based architecture, allowing users to extend its capabilities beyond standard HTTP requests. This makes it suitable for specialized protocols or workflows. It's an open-source option for developers needing high customization potential.
- Keywords: Insomnia fork, Local, Privacy-focused, Offline, Open-source Insomnia alternative.
- Description: Insomnium was created as a direct fork of Insomnia specifically to remove the mandatory cloud sync and account requirements introduced by Kong. It aims to provide the familiar Insomnia UX while ensuring all data remains 100% local and private. It's the quintessential privacy-focused, offline, open-source Insomnia alternative for users who liked the original interface but prioritize data locality. (Note: As with any fork, users should check the repository for ongoing maintenance activity).
- Keywords: HTTP inspection tool, HTTP/2, HTTP/3, Rust.
- Description: Pororoca is primarily an HTTP inspection tool with strong support for modern protocols like HTTP/2 and HTTP/3, alongside HTTP/1.1. Built with Rust for performance, it allows detailed analysis and debugging of interactions using these newer protocols, capabilities often lacking in older clients. While it can send requests, its focus on inspection and advanced protocol support differentiates it.
- Keywords: Windows REST API client, Fluent design, Resource-efficient, Open-source.
- Description: Nightingale is a modern, open-source REST API client specifically designed for Windows, utilizing Fluent design principles for a native look and feel. It emphasizes performance and resource efficiency. It supports collections, environments, request history, and various authentication methods, making it a polished choice for developers primarily on the Windows platform.
- Keywords: Desktop app, API Client, API Mocking, Modify HTTP requests, Intercept.
- Description: In addition to its browser extension, Requestly offers a full-featured desktop app (Windows, macOS, Linux). This provides the same powerful combination of API client, API mocking, request/response interception, and modification capabilities in a standalone application. Ideal for users who prefer a dedicated tool or need to intercept traffic system-wide or from non-browser applications.
- Keywords: Native, Lightweight, Multiplatform, Free HTTP client.
- Description: Cartero aims to be a native, lightweight, multiplatform, and free HTTP client. It focuses on providing the essential API request functionality without excessive complexity, using native UI toolkits (like GTK on Linux) for better performance and OS integration. A good option for users seeking a simple, fast, no-frills desktop client.
These tools bring API interaction directly into your code editor, minimizing context switching and keeping API testing close to development.
- Keywords: VS Code extension, Send HTTP request, Text-based, IDE integration.
- Description: An immensely popular VS Code extension, REST Client allows developers to define and send HTTP/GraphQL requests directly from plain text files (
.httpor.rest). It uses a simple, intuitive syntax, supports environment variables (via VS Code settings), code snippets, response saving, cURL command generation, and more. Clicking "Send Request" executes the query, displaying the response in a separate pane. Its tight integration makes it a favorite free Postman alternative for VS Code users.
- Keywords: VS Code extension, Lightweight REST API Client, GUI inside VS Code.
- Description: Another highly popular VS Code extension, Thunder Client provides a lightweight, GUI-based REST API client experience directly within the editor, often cited as a direct Postman alternative for VS Code users. Unlike the text-based approach of REST Client, Thunder Client offers a graphical interface similar to standalone clients (Postman, Insomnia) but integrated into VS Code's sidebar. It supports collections, environment variables, scripting, and testing, offering a more visual workflow without leaving the IDE. Its ease of use and feature set make it extremely popular.
- Keywords: Firefox add-on, REST debugger, Browser extension.
- Description: A simple browser extension for Firefox providing a basic UI to construct and send HTTP requests and view responses. Useful for quick debugging or testing of web services directly from within Firefox.
- Keywords: Emacs HTTP client, Text-based, IDE integration.
- Description: For users of the Emacs editor,
restclient.elenables defining and executing HTTP requests from within plain text buffers using a specific format. It integrates seamlessly into Emacs workflows, allowing responses to be viewed and manipulated within the editor.
- Keywords: Emacs HTTP client, Organize requests, IDE integration.
- Description: Another option for Emacs users,
verbfocuses on organizing and sending HTTP requests from within the editor, providing an alternative workflow and feature set torestclient.el.
- Keywords: Neovim HTTP client, Lua, Fast, IDE integration.
- Description: A fast, Lua-based HTTP client specifically for Neovim users.
rest.nvimallows defining requests in.httpfiles (similar to VS Code REST Client) and executing them directly within Neovim, leveraging the editor's modern capabilities for a performant experience.
- Keywords: Neovim REST Client, Minimalist, IDE integration.
- Description: Positioned as a minimal REST client interface for Neovim,
kulala.nvimlikely offers core request-sending functionality with a focus on simplicity and potentially less configuration overhead compared torest.nvim.
Indispensable for automation, scripting, and terminal enthusiasts, CLI tools offer performance, composability, and easy integration into CI/CD pipelines.
- Keywords: curl, Command line tool, Data transfer, URL syntax, CLI.
- Description: The foundational, ubiquitous command-line tool for transferring data using URL syntax. Active since 1998,
curlis incredibly powerful and versatile, supporting numerous protocols (HTTP, HTTPS, FTP, SMB, LDAP, etc.) with extensive options for fine-grained control. While its syntax can be complex, its reliability and presence on virtually every system make it essential for scripting and basic API testing. It's the benchmark against which other CLI clients are often measured.
- Keywords: HTTPie, Human-friendly HTTP client, CLI, JSON support, Syntax highlighting.
- Description: HTTPie aims to make CLI interaction with HTTP APIs as human-friendly as possible. It provides an intuitive syntax, sensible defaults, built-in JSON support, syntax highlighting, and formatted output, making it significantly easier and more pleasant to use for common API calls than raw
curl. A very popular free Postman alternative for terminal users seeking better usability.
- Keywords: grpcurl, gRPC CLI, Command-line tool, gRPC reflection.
- Description: The
curlequivalent for gRPC.grpcurlallows interacting with gRPC servers from the command line, enabling service discovery (via reflection or proto files), listing methods, and invoking RPC calls. Essential for scripting and testing gRPC services in a terminal environment.
- Keywords: Friendly HTTP requests, Fast CLI tool, Rust.
- Description: Built with Rust,
xhis another friendly and fast CLI tool for sending HTTP requests, positioned as an alternative to HTTPie. It offers similar usability improvements overcurl, focusing on performance and a pleasant user experience with features like simplified syntax and colored output.
- Keywords: Modern API client, Terminal-based.
- Description:
postingaims to be a modern API client living entirely in the terminal, potentially offering a more interactive or structured experience than simple request/response tools, possibly managing contexts or sessions within its interface.
- Keywords: curl frontend, HTTPie syntax, CLI.
- Description:
curliecleverly acts as a frontend forcurl, allowing users to use HTTPie-like syntax while leveraging the power and ubiquity of the underlyingcurlexecutable. It translates the user-friendly commands into the appropriatecurloptions, offering a bridge between HTTPie's ease of use andcurl's extensive capabilities.
- Keywords: .NET HTTP client, CLI, REPL, OpenAPI, Swagger integration.
- Description: Developed by Microsoft as part of the .NET ecosystem, HttpRepl is a lightweight, cross-platform CLI tool providing an interactive REPL (Read-Eval-Print Loop) for exploring and testing RESTful APIs. It allows navigation through API paths using familiar shell commands (
ls,cd), integrates with OpenAPI (Swagger) definitions for better discovery, and supports standard HTTP verbs. It's particularly convenient for .NET developers but works with any REST API.
- Keywords: Meta HTTP client, curl wrapper, wget wrapper, httpie wrapper, CLI.
- Description:
ainfunctions as a meta-client in the terminal. Instead of performing HTTP requests itself, it acts as a wrapper, providing a simplified syntax layer that translates commands to execute using backend tools likecurl,wget, orhttpie(whichever is available). This leverages the robustness of established tools while offering a potentially easier command structure.
- Keywords: gRPC client, CLI, REPL, Expressive gRPC client.
- Description: Evans is another feature-rich CLI client for gRPC services, branding itself as a "more expressive universal gRPC client". It provides both an interactive REPL mode for exploration (with auto-completion) and a CLI mode suitable for scripting. It supports server reflection, loading proto files, handling metadata, and various output formats, serving as a powerful alternative to
grpcurl.
- Keywords: HTTP file execution, CLI, REST, SOAP, GraphQL, gRPC, VS Code integration.
- Description: httpYac bridges IDE/text-based definitions with CLI execution. It uses
.httpfiles (similar syntax to the VS Code REST Client) to define requests for REST, SOAP, GraphQL, and gRPC. Its CLI tool then executes these files, making it excellent for managing complex requests as code and running them in automated environments (like CI/CD). It supports environment variables, scripting hooks, and response handling. It also has a companion VS Code extension.
- Keywords: Terminal API client, TUI, Simple Postman alternative CLI.
- Description: ATAC (API Terminal Automated Client) aims to provide a simple, Postman-like experience within the terminal. It likely offers a TUI (Text User Interface) or a straightforward command structure for defining, organizing (perhaps in collections), executing, and viewing HTTP requests, focusing on ease of use for common API testing tasks directly from the command line.
While many API clients include basic assertion capabilities, the tools in this section are specifically designed for automating API tests, often integrating into CI/CD pipelines. They typically treat tests as code or structured data, enabling complex scenarios, data-driven testing, comprehensive reporting, and robust validation. Some popular commercial tools often mentioned in this context include Katalon Studio, SoapUI, TestSigma, Assertible, ReadyAPI, and Apigee (though Apigee is more an API management platform), while JMeter is a powerful open-source tool focused on load testing but usable for functional API tests. The following are primarily open-source frameworks focused on functional and integration API testing.
- Keywords: API Test Automation framework, Declarative testing, YAML, CI/CD integration, Open-source.
- Description: Step CI is an open-source API test automation framework emphasizing simplicity and CI/CD integration. Tests are defined declaratively using YAML, specifying API calls, data extraction rules (to chain requests), and assertions. It's designed for ease of use, allowing developers and QA teams to quickly create and maintain automated API tests as part of their development lifecycle.
- Keywords: Plain text HTTP requests, API testing, CLI, Assertions, CI/CD.
- Description: Hurl executes HTTP requests defined in simple, human-readable plain text files (
.hurl). This format allows specifying request details (method, URL, headers, body) alongside assertions on the response (status, headers, body content via JSONPath, XPath, regex, etc.) and capturing values for subsequent requests. Hurl acts as a CLI tool that runs these files, making it ideal for integration testing within CI/CD pipelines due to its simplicity and dependency-free nature.
- Keywords: Karate testing framework, BDD, API test automation, Mocks, Performance testing, Open-source.
- Description: Karate is a popular open-source framework that unifies API test automation, mocks, performance testing, and even UI automation. It uses a BDD (Behavior-Driven Development) syntax based on Gherkin, making tests readable by diverse teams. Karate excels at handling JSON and XML natively, provides powerful assertion capabilities, and allows embedding JavaScript for complex logic if needed. It's often cited as a comprehensive alternative for teams looking beyond basic Postman tests.
- Keywords: Automated RESTful API testing, Pytest plugin, YAML, MQTT, Open-source.
- Description: Tavern is a Pytest plugin for automated RESTful API testing, using a declarative YAML format. Its tight integration with Pytest allows leveraging the extensive Python testing ecosystem. Tavern supports complex scenarios, validation using JSON Schema, and extensibility for different protocols (including built-in MQTT support).
- Keywords: Integration tests, Test runner, YAML, Executors, Open-source.
- Description: Venom is a versatile open-source test runner developed by OVHcloud. It allows writing test cases in YAML and supports various executors (HTTP, gRPC, WebSockets, databases, SMTP, SSH, etc.), making it suitable for complex integration tests that span multiple services and protocols.
- Keywords: Python REST testing, API testing framework, Basic testing, JSON.
- Description: A relatively simple Python-based REST testing and API microbenchmarking tool. Tests are defined in JSON or YAML format, focusing on basic test structures, validations, and extraction mechanisms. It's a straightforward option for teams comfortable with Python looking for a minimal framework.
- Keywords: Scenario runner, API testing tool, Go, Debugger.
- Description:
runnis a tool and library built in Go for running operations defined in a scenario file (YAML). It supports API testing (HTTP/gRPC), database queries, command execution, and includes features like a step-by-step debugger, making it useful for complex end-to-end scenario testing.
- Keywords: End-to-end scenario testing, HTTP server testing, gRPC server testing, Go.
- Description: Also built in Go,
scenarigois an end-to-end scenario testing tool focused on HTTP and gRPC servers. It allows defining test scenarios in YAML, referencing.protofiles for gRPC, and writing assertions to validate complex application behaviors.
- Keywords: Specification-centric API testing, Property-based testing, OpenAPI, GraphQL, Open-source.
- Description: Schemathesis takes a unique, specification-centric approach to API testing. It reads your OpenAPI or GraphQL schema and automatically generates test cases based on the defined constraints (using property-based testing principles). This helps find edge cases and specification violations that manual testing might miss. It integrates well with Python testing frameworks.
- Keywords: API Blueprint, OpenAPI testing, Language-agnostic, HTTP API testing.
- Description: Dredd is a language-agnostic HTTP API testing tool that validates if your API implementation matches its documentation (API Blueprint or OpenAPI/Swagger). It reads the spec, makes requests to your live API server, and compares the results against the documented expectations. Useful for ensuring documentation stays synchronized with the actual API behavior.
- Keywords: RAML testing, REST API automated testing.
- Description:
abaois specifically designed for automated testing of REST APIs documented using RAML (RESTful API Modeling Language). It functions similarly to Dredd but focuses on the RAML specification format.
- Keywords: API testing framework, YAML/JSON, Go/Python, Load testing support.
- Description: HttpRunner is a popular open-source API testing framework supporting tests defined in YAML or JSON. It has implementations in both Go and Python (HttpRunner v4 onwards focusing on Go). It supports various features like data-driven testing, complex scenarios, hooks, and can also be used for basic load testing.
- Keywords: Load testing tool, Performance testing, JavaScript, Go, Open-source.
- Description: While primarily known as a modern, developer-centric load testing tool, k6 (by Grafana) can also be used for functional API testing. Tests are written in JavaScript (ES2015+) and executed by a high-performance Go runtime. It integrates well into developer workflows and CI pipelines, focusing on performance and reliability under load, but its scripting capabilities allow for functional assertions too.
- Keywords: Load testing, Performance testing, Cloud-scale, YAML, JavaScript, Open-source.
- Description: Similar to k6, Artillery is an open-source tool focused on load testing at cloud-scale. Test scenarios are typically defined in YAML, with support for custom logic written in JavaScript. While its main goal is performance testing, it includes features for making assertions and validating responses, allowing it to be used for complex functional API testing scenarios as well.
Based on common searches and discussions, here are answers to some frequently asked questions:
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Is there anything better than Postman? "Better" is subjective and depends entirely on your needs.
- For users prioritizing privacy, offline access, and Git integration, Bruno is often considered better.
- For a free, feature-rich web/PWA experience, Hoppscotch is frequently cited as a superior alternative.
- For seamless VS Code integration, VS Code REST Client or Thunder Client are often preferred.
- For CLI power users, HTTPie or
curl(with perhapscurlieorxh) offer different advantages. - For robust automated testing, dedicated frameworks like Karate, Step CI, or Hurl might be better suited than Postman's built-in testing.
- Some all-in-one commercial tools like Apidog or Katalon Studio position themselves as integrated platforms offering broader lifecycle support, which some may find "better." Ultimately, the "best" Postman alternative is the one that best fits your specific workflow, priorities (privacy, cost, collaboration, offline use), and technical requirements (protocols, testing complexity).
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How to post API without Postman? You have numerous options!
- Desktop GUI Clients: Use Bruno, Insomnia/Insomnium, Hoppscotch (via PWA), Nightingale, Yaak, Requestly Desktop, etc.
- Web-Based Clients: Use Hoppscotch, Restfox, Firecamp, Requestly Extension, etc., directly in your browser.
- IDE Integrations: Use VS Code REST Client, Thunder Client (VS Code),
restclient.el(Emacs),rest.nvim(Neovim), etc. - CLI Tools: Use
curl, HTTPie,xh,posting,httpYac, etc., from your terminal. This is ideal for scripting and automation. - Programmatically: Use HTTP client libraries within your preferred programming language (e.g.,
requestsin Python,axiosin JavaScript,HttpClientin C#/.NET,OkHttpin Java/Kotlin). - API Testing Frameworks: Use tools like Karate, Hurl, Step CI to define and execute POST requests as part of automated test suites.
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Which is better, Swagger or Postman? They serve different primary purposes but have overlapping functionality:
- Swagger (OpenAPI Specification + Swagger UI): Primarily focuses on API design and documentation. The spec defines the contract, and Swagger UI provides interactive documentation generated from that spec, allowing basic interactive testing. Its strength is in defining and communicating the API structure.
- Postman (and its alternatives): Primarily focuses on API interaction, testing, and development workflow. They are feature-rich clients for sending requests, managing environments/collections, writing complex test scripts (assertions, chaining), mocking, monitoring, and collaboration. Conclusion: They are complementary tools. Use Swagger/OpenAPI to define and document your API. Use Postman or an alternative like Bruno, Hoppscotch, or VS Code REST Client for in-depth testing, exploration, and development against that API. You often use Swagger UI for quick interactive checks based on the docs, and a tool like Postman/Bruno for more complex testing scenarios and development workflows.
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Do people still use Postman? Yes, absolutely. Postman remains a very popular and widely used tool in the API development space, despite the growing interest in alternatives. It has a large user base, extensive features built over many years, and strong brand recognition. However, the recent changes regarding mandatory accounts and cloud sync have undeniably caused a significant portion of the community (especially those prioritizing privacy, offline use, or open-source principles) to evaluate and migrate to alternatives like those listed in this document. The API client landscape is now more diverse than ever.
The API client landscape is richer and more diverse than ever before. While Postman and Insomnia played pivotal roles in popularizing graphical API interaction, concerns around cloud dependence, privacy, and cost have catalyzed the growth of exceptional open-source and free alternatives.
Whether you prioritize offline-first operation (Bruno, Restfox), a comprehensive web-based experience (Hoppscotch), seamless IDE integration (VS Code REST Client, Thunder Client), CLI efficiency (HTTPie, curl, Hurl), specialized protocol support (gRPC UI, ezy, Firecamp), or robust automated testing (Karate, Step CI, Schemathesis), there is a high-quality, community-driven tool available.
This list (Awesome API Clients) provides a starting point for exploring these powerful Postman alternatives and Insomnia alternatives. Evaluate them based on your specific needs – be it individual use, team collaboration, protocol requirements, testing complexity, or philosophical alignment regarding open source and data privacy. The power to choose the right tool for your API workflow, without compromises, is firmly in your hands.