Best Free API Testing Tools Compared: Thunder Client, Bruno, and Hoppscotch
Postman’s dominance in API testing has an unintended side effect: a lot of developers now pay for features they rarely use, or route sensitive request data through a cloud account they never wanted. That’s why three free alternatives—Thunder Client, Bruno, and Hoppscotch—keep coming up in team discussions. Each takes a fundamentally different approach to the same job: sending HTTP requests, inspecting responses, and organizing collections.
This comparison looks at how the three differ in architecture, workflow, and cost, so you can pick the one that fits your team rather than the one with the loudest marketing.
The Contenders at a Glance
| Thunder Client | Bruno | Hoppscotch | |
|---|---|---|---|
| Form factor | VS Code extension | Desktop app (also VS Code extension) | Browser app + desktop app + CLI |
| License | Freemium (free tier) | Open source (MIT) | Open source (MIT) |
| Data storage | Local by default; cloud sync is paid | Plain files in your repo | Local storage in browser; self-host for team sharing |
| Git-friendly | Partially (export/import) | Yes, by design | Yes (collection files) |
| Best for | VS Code users who want zero context switching | Teams that want API collections in version control | Quick tests, sharing, and CI pipelines |
Thunder Client: The VS Code Native
Thunder Client lives inside Visual Studio Code as an extension, and that’s its entire pitch. If you already write code in VS Code, you can fire off a request without opening another window. For developers who spend most of the day in the editor, that absence of context switching is a real productivity gain.
The free tier covers the essentials well: HTTP methods, headers, query parameters, request bodies, environment variables, and a reasonably capable test runner with basic assertions. Collections and environments are stored locally, which means your requests stay on your machine unless you opt into the paid cloud sync.
The trade-offs show up as you scale. The free tier limits some advanced features—among them certain collaboration and sync capabilities—and the interface, while clean, feels more compact than a dedicated API client. Git integration is workable through export and import, but it isn’t the native file-based workflow that Bruno offers. For an individual developer or a small team already standardized on VS Code, Thunder Client is often the path of least resistance.
Bruno: Collections as Code
Bruno made a deliberate architectural bet: API collections should be plain files stored on disk, not records locked inside a proprietary app or cloud account. Every request, environment, and folder in Bruno is a human-readable file you can commit to Git, review in a pull request, and diff like any other source code.
That design choice solves a problem teams feel acutely. With cloud-based tools, collection changes live in someone’s account. With Bruno, a change to an endpoint’s headers shows up in the same pull request as the code change that requires it. Reviewers see both. History is preserved. Nothing depends on a vendor staying in business or keeping a free tier intact.
Bruno is open source under the MIT license, and the core desktop app is free. It runs offline by default, which matters for teams working with internal APIs or in regulated environments where request data can’t leave the network. It also ships a VS Code extension and a CLI for running collections in CI.
The costs are mostly cultural rather than financial. Bruno is younger than Postman, so its ecosystem of integrations and community-shared collections is smaller. Teams accustomed to clicking “share” in a cloud tool need to adjust to a Git-based workflow—which some will see as friction and others as the whole point. If your team already treats configuration as code, Bruno will feel natural almost immediately.
Hoppscotch: Lightweight, Fast, and Built for Sharing
Hoppscotch started as a browser-based API client and has grown into a broader platform with a web app, a desktop app, and a command-line tool. Its defining traits are speed and accessibility: open a browser tab, send a request, get a response. There’s no install step for the web version, which makes it handy for quick checks on a machine that isn’t yours.
The open-source core is MIT licensed and free to self-host, which appeals to organizations that want a shared API workspace without routing traffic through a third-party cloud. The hosted version offers a free tier with usage limits, and paid plans add team collaboration features. The CLI supports running collections in CI, so Hoppscotch can serve as both an interactive tool and a pipeline component.
Hoppscotch supports the expected protocol range—REST, GraphQL, WebSocket, and others—and its interface is among the fastest to load of the three. The trade-offs: the web app’s data lives in browser storage unless you’re on a paid plan or self-hosting, which complicates team sharing on the free tier. Browser-based testing can also hit CORS restrictions that desktop clients avoid, though the desktop app sidesteps that. Git-based workflows are possible but less central to the product’s design than they are in Bruno.
How to Choose
The decision comes down to where you want your API collections to live and how your team works.
Choose Thunder Client if you live in VS Code, work mostly solo or in a small team, and want the lowest-friction way to test APIs without leaving your editor. The free tier is generous enough for everyday use.
Choose Bruno if you want collections versioned alongside your code, you value open-source licensing and offline operation, or your organization has data-residency concerns that rule out cloud-synced request data. It’s the strongest fit for teams that already review configuration changes through Git.
Choose Hoppscotch if you need something you can open instantly in a browser, you want a self-hostable shared workspace, or you’re assembling a CI pipeline and want a CLI that’s part of the same tool. It’s also the easiest of the three to introduce to someone who has never used an API client.
One practical note: these tools aren’t mutually exclusive. Many developers keep Thunder Client installed for quick in-editor checks while their team’s canonical collection lives in Bruno or a self-hosted Hoppscotch instance. The free tiers make that kind of overlap cheap.
The Bottom Line
All three tools cover the core job—sending requests and inspecting responses—without asking for a credit card. The meaningful differences are architectural: Thunder Client optimizes for staying inside your editor, Bruno optimizes for treating API collections as versioned source code, and Hoppscotch optimizes for instant access and self-hostable sharing. Pick based on where you want your collections to live and how your team collaborates, and you’ll end up with a tool that fits your workflow instead of one you have to work around.