Featured tools include:

• Hoppscotch – 58k+ GitHub stars
• Bruno – Offline-first, Git-friendly
• Insomnia – Powerful open-source core (now owned by Kong)
• Mockoon – Popular for API mocking

Key Takeaway: Use this as your starting point. Shortlist 2-3 tools based on maintenance signals and summaries, then test hands-on.

Website: https://openalternative.co/alternatives/postman

2. Insomnia (by Kong)

Insomnia, now under the Kong umbrella, is a powerful open-source API client and one of the most feature-rich alternatives to Postman. It offers a sleek, cross-platform interface for designing, documenting, and testing APIs with broad protocol support—REST, GraphQL, gRPC, and WebSockets.

What sets Insomnia apart is its native Git Sync feature. Teams can manage API specs and test suites version-controlled within their Git repositories—a significant advantage over cloud-only sync. The Inso CLI enables seamless CI/CD integration for automated API testing. For organizations seeking robust API management, explore the broader API gateway ecosystem.

Key Features and Considerations

The free tier includes unlimited request collections and environments—more than enough for individual developers and small teams. Paid plans unlock advanced collaboration features like role-based access control (RBAC) and centralized organization management.

• Pros:
  • Extensive protocol support (REST, GraphQL, gRPC, WebSockets).
  • Native Git Sync for version-controlled API collections.
  • Powerful Inso CLI for CI/CD pipeline automation.
  • Generous free tier with core features unlocked.
• Cons:
  • Advanced team collaboration and security features are locked behind paid tiers.
  • Optional cloud sync may present data residency concerns for some organizations.

Website: https://insomnia.rest

3. Hoppscotch

Hoppscotch is a lightweight, open-source, browser-first API development suite—one of the most accessible alternatives to Postman. Start sending REST or GraphQL requests directly from your browser in seconds, no installation required. For teams prioritizing data privacy, Hoppscotch offers a well-documented path to self-host the entire platform.

The free cloud-hosted version is generous: unlimited workspaces, collections, and requests—more than enough for most developers and small teams. This removes the immediate paywalls found in other tools. For growing organizations, the self-hosted enterprise edition provides SSO and dedicated support, scaling with your security and compliance needs.

Key Features and Considerations

Hoppscotch balances a fast, web-centric workflow with the option to self-host for enhanced security. Active development and a transparent public status page inspire confidence in the platform's reliability. Core functionality is free; enterprise-grade features require paid or self-hosted enterprise plans.

• Pros:
  • Extremely lightweight and fast, running directly in the browser.
  • Generous free tier with unlimited team workspaces and requests.
  • Strong open-source foundation with a clear path to self-host for privacy.
  • Actively maintained with a transparent development process.
• Cons:
  • Audit logs and SSO are exclusive to paid/enterprise tiers.
  • Browser-first design may not suit users who prefer dedicated desktop apps.

Website: https://hoppscotch.com

4. Bruno

Bruno is an open-source API client that prioritizes offline-first functionality and Git-native workflows. Unlike cloud-centric tools, Bruno stores API collections on your local filesystem as plain-text .bru files. This makes it lightweight, fast, and ideal for developers who version control API tests alongside application code.

There's no cloud sync by design—eliminating data residency concerns and vendor lock-in. Bruno offers a clean cross-platform desktop app, a CLI for automation, and a VS Code extension. This Git-centric model treats API collections as part of your codebase, simplifying collaboration. Explore more open-source Bruno alternatives.

Key Features and Considerations

Bruno’s core open-source version is completely free and highly capable, covering all essential API testing needs for individual developers and teams. For advanced features like in-collection secret management, performance testing, and enhanced script libraries, a one-time purchase of the Golden Edition is available, which avoids recurring subscription costs.

• Pros:
  • Offline-first and local-only, ensuring excellent privacy and data control.
  • Git-native workflow using plain-text files simplifies version control.
  • Lightweight, fast, and available as a desktop app, CLI, and VS Code extension.
  • No mandatory cloud sign-up or subscription for core features.
• Cons:
  • No built-in cloud sync—may be a drawback for teams accustomed to it.
  • Some advanced features require the commercial Golden Edition.

Website: https://www.usebruno.com

5. Yaak

Yaak is a modern, open-source alternative to Postman, built by the original creator of Insomnia. Designed from the ground up with privacy, offline-first functionality, and developer control at its core, Yaak commits to local-only data storage with zero telemetry. Your sensitive API information stays encrypted on your machine.

Yaak resists vendor lock-in with seamless Git-based workflows. Collections and environments are stored in plain-text formats, easy to version control and share alongside your codebase. Its snappy, multi-window interface and extensible plugin system for custom authentication and templating cater to developers who demand speed and flexibility.

Key Features and Considerations

Yaak is completely free and open-source—no paid tiers, full feature set included. It supports imports from Postman, Insomnia, and OpenAPI specifications, simplifying migration.

• Pros:
  • Privacy-first architecture with local-only storage and zero telemetry.
  • Git-friendly plain-text storage for easy version control.
  • Fast, modern UI with cross-platform support (macOS, Windows, Linux).
  • Completely free and open-source with a transparent roadmap.
• Cons:
  • Plugin ecosystem is still growing.
  • Lacks advanced team governance features found in enterprise platforms.

Website: https://yaak.app

6. Thunder Client (VS Code extension)

For developers who live inside Visual Studio Code, Thunder Client integrates API testing directly into the editor. This popular extension eliminates context-switching with a simple GUI for composing requests, managing environments, and running tests. API interaction feels like a native part of the coding process.

Thunder Client balances simplicity and power. It provides collections, environment variables, and automated testing in a clean interface. Git Sync keeps collections version-controlled alongside your codebase, and a dedicated CLI enables CI/CD integration for automatic API contract validation.

Key Features and Considerations

Thunder Client operates on a freemium model. The free version is for non-commercial use with limitations; paid tiers unlock SSO, encrypted environment variables, and support for gRPC, WebSockets, and SSE.

• Pros:
  • Seamless integration directly within the VS Code environment.
  • Simple, clean UI that is easy to learn and use.
  • Supports collections, environments, Git Sync, and CI/CD automation.
  • Paid tiers offer advanced security and protocol support.
• Cons:
  • Free version restricted to non-commercial use with feature limits.
  • Not a standalone app—VS Code required.
  • Some friction reported when hitting usage limits.

Website: https://www.thunderclient.com

7. HTTPie

HTTPie started as a beloved, human-friendly CLI HTTP client and has evolved into a full suite with desktop and web applications. It excels for developers who prioritize terminal-first workflows, scripting, and rapid API exploration. The philosophy of simplicity carries from CLI to GUI—clean, intuitive, offline-capable, no account required.

HTTPie blends a powerful CLI with a user-friendly GUI. Send requests from your terminal using expressive syntax, then organize them into collections within the desktop or web app. This dual-interface approach serves both quick, scripted interactions and structured, long-term projects. For intercepting and modifying requests, explore traffic modification tools.

Key Features and Considerations

The CLI is free and open source; desktop and web apps offer a generous free plan. Paid plans add team collaboration, enhanced sync, and dedicated support for organizations needing centralized API management.

• Pros:
  • Excellent for rapid API exploration and automation via its human-friendly CLI.
  • No forced sign-in for the desktop app reduces friction for local development.
  • Well-respected open-source project with easy installation on major operating systems.
• Cons:
  • Team collaboration less extensive than enterprise-focused suites.
  • GUI still evolving; feature depth may lag more mature competitors.

Website: https://httpie.io

8. Paw (RapidAPI for Mac)

Paw, now RapidAPI for Mac, has long been a favorite among macOS developers for its beautiful, powerful native API client. It offers a polished, Mac-first experience for building requests, generating documentation, and inspecting responses. A strong alternative to Postman for teams embedded in the Apple ecosystem.

Paw focuses on the entire API lifecycle, from design to consumption. It excels at importing and generating OpenAPI, Swagger, and RAML formats, simplifying client code and documentation generation. Team collaboration ties into RapidAPI Studio, but the core app remains highly capable for crafting and debugging complex requests with dynamic values and environment management.

Key Features and Considerations

Paw is now free for personal and professional use—a significant change from its previous paid model. Team synchronization is managed through a RapidAPI account.

• Pros:
  • Exceptional native macOS experience with a polished and intuitive UI.
  • Strong documentation and client code generation capabilities.
  • Excellent support for importing and exporting API description formats.
  • Now free to use, removing a previous barrier to entry.
• Cons:
  • macOS-only—unsuitable for cross-platform teams.
  • Team collaboration relies on the RapidAPI ecosystem.

Website: https://paw.cloud

9. SoapUI and ReadyAPI

For organizations invested in enterprise-grade API quality assurance, SoapUI and ReadyAPI present a powerful, mature alternative to Postman. SoapUI Open Source handles SOAP and REST API testing; its commercial sibling ReadyAPI by SmartBear expands into advanced functional, security, and performance testing.

This platform excels in complex, data-driven testing where teams need sophisticated test cases without extensive coding. ReadyAPI's point-and-click interface simplifies assertions and request chaining, while load testing and service virtualization simulate real-world conditions. A go-to for QA teams and DevOps engineers. For backend developers, explore backend-as-a-service platforms.

Key Features and Considerations

Teams can start with free SoapUI Open Source for fundamental testing and graduate to licensed ReadyAPI for enterprise-level automation without changing core tooling. ReadyAPI's licensing targets professional teams requiring dedicated support.

• Pros:
  • Enterprise-grade test automation, reporting, and CI integrations (ReadyAPI).
  • Extensive ecosystem with vast documentation and commercial support.
  • Strong focus on SOAP services, which is a key differentiator.
  • Free, open-source version available for foundational testing needs.
• Cons:
  • Java-based client feels heavier than modern lightweight alternatives.
  • ReadyAPI licensing is a significant investment for smaller teams.

Website: https://www.soapui.org

10. Kreya

Kreya is a privacy-first, desktop-native API client with exceptional support for modern protocols, particularly gRPC. It appeals to developers who prioritize local data control and work with microservices beyond REST. Strong support for gRPC, WebSockets, and SSE makes it powerful for testing real-time applications.

All project data is stored in Git-diffable files on your machine—no cloud sync concerns. A dedicated CLI and Docker image enable seamless CI/CD integration. Kreya simplifies migration with importers for Postman, Insomnia, OpenAPI, and Protobuf files.

Key Features and Considerations

The free version offers a generous feature set for individual developers. Paid plans add snapshot testing and templating; enterprise terms are available for larger teams.

• Pros:
  • Excellent protocol coverage, with first-class support for gRPC, REST, WebSockets, and SSE.
  • Strong privacy and local-first approach with Git-friendly file storage.
  • Powerful CLI and Docker image for easy automation and CI/CD integration.
  • Clear documentation and an actively developed, responsive platform.
• Cons:
  • Smaller ecosystem and community compared to Postman.
  • Advanced testing and templating features require paid tiers.

Website: https://kreya.app

Top 10 Postman Alternatives: Side-by-Side Feature Comparison

Final Thoughts

The API tooling landscape is richer than ever. While Postman dominated for years, evolving workflows, privacy demands, and the push toward open-source have paved the way for a new generation of tools. Finding alternatives to Postman isn't about a one-to-one replacement—it's about discovering a tool that fits your specific needs and environment.

The "best" API client is subjective. What works for a solo developer prototyping rapidly may fall short for an enterprise team requiring self-hosted collaboration and strict security controls. The one-size-fits-all era is over.

How to Choose

Consider these factors:

• Workflow Integration: Live in your IDE? Thunder Client eliminates context switching.
• Collaboration vs. Solo: Teams benefit from Insomnia (Git Sync) or self-hosted Hoppscotch. Solo developers thrive with Bruno's offline-first approach.
• Privacy: Need data off third-party clouds? Focus on Hoppscotch, Bruno, and Yaak.
• Protocol Support: Working with gRPC or SOAP? Kreya and SoapUI are purpose-built.
• Speed: Need something fast and lightweight? HTTPie's CLI or Hoppscotch's browser access deliver.

Next Steps

1. Shortlist 2-3 candidates based on the comparison table.
2. Run a pilot test on a small project. Import a collection, set up an environment, run requests, write a test.
3. Evaluate the feel. Is it intuitive? Fast? Does it get out of your way? This often decides it.

The days of being locked into a single ecosystem are over. Open-source platforms make it easier than ever to find alternatives to Postman that respect your privacy, budget, and workflow. The tooling landscape will only keep evolving—empowering developers to build better, faster, and more securely.

These GUI/CLI/mocking tools offer powerful alternatives to Postman. If none fit your needs, explore OpenAlternative for more free and open source options.