Reviewed by Marco Wollank
Replace today:
Postman
The Best Open-Source API Clients in 2026
Private alternatives to Postman, vetted against our public criteria.
Showing 2 of 2
Hoppscotch
Fast, lightweight open-source API client that runs in the browser and can be self-hosted on your own server. No install needed to start.
No matches for those filters.
How they compare
| Tool | Stores requests | Based in | Cost |
|---|---|---|---|
| | Local files (Git) | · | Free |
| | Browser or self-host | United Kingdom | Free |
Every request you build holds the keys to your API: the auth tokens and environment secrets you paste into a variable and forget. A cloud-first client like Postman uploads all of it the moment you sign in, because the account sync is how the product works. An open-source API client does the same job without that bargain. Your requests stay on your own disk or your own server, and the account becomes optional instead of mandatory.
Why you can’t just turn off the cloud in Postman
There is no setting that makes a cloud-first client local. The sign-in and the background sync of your collections and environment variables are the architecture, not a toggle, so the requests and secrets you save are uploaded to keep that workspace consistent across your devices. You can be careful about what you type into a variable, but the design pushes everything toward the cloud by default, and a single shared workspace can carry a teammate’s token to a server none of you administer. The only real fix is a client that never assumes an account, which is what each pick on this page is built around.
How we pick
Every client here is measured against our public listing criteria, with one focus that matters most for this category: where your requests and secrets live by default. We list a client only when it is open source and keeps your collections on infrastructure you control without forcing a login, while doing the everyday work of building and testing an API well enough that we would reach for it ourselves. We say plainly where each one compromises, so you are weighing a real tradeoff rather than a slogan.
What to look for in an API client
Start with storage. A client that writes each request to a plain text file lets you commit the collection to Git and review a change in a pull request, with secrets kept out of anyone else’s cloud. Next, check whether an account is required to do basic work or merely offered for sync, since a mandatory login is a mandatory upload. Then look at how secrets are handled: a good client keeps environment variables where you can see them and never ships them off as a condition of use. Finally, confirm it imports a Postman collection, so leaving is a migration and not a rewrite. The common thread is control, which is exactly what a cloud-only tool takes away.
What about team collaboration and sync?
This is the honest objection, because shared cloud workspaces are convenient. The answer is that control and collaboration are not opposites. Bruno stores collections as files, so your team collaborates through the same Git workflow you already use for code, with history and review built in. Hoppscotch can be self-hosted, so a team gets a shared instance on its own server instead of a vendor’s. You trade a turnkey cloud for a setup you own, and for most teams that already live in Git the workflow feels familiar rather than harder.
How to switch
Export your existing collection from Postman, then import it into the client you chose, and your saved requests come across. Re-enter your environment secrets by hand, since they do not travel in an export, and that is the moment they move back under your control. From there, commit the collection to your repository or stand up a self-hosted instance, and your API work stops feeding a workspace you do not own. Give it a week of daily use and the habit settles, because sending a request works exactly as it did before.
Frequently asked
- Why does Postman want me to sign in just to send a request?
- Because the account is how it syncs your collections and their saved history to its cloud. That sync is the product, not a side feature, so the client is built around a logged-in workspace. An open-source client treats the account as optional and keeps your requests on your own disk by default.
- Are my API tokens and secrets safe in a cloud API client?
- They are only as safe as the vendor's servers and your trust in them. Anything you put in an environment variable gets uploaded so it can sync, which means a real secret can leave your machine without you thinking about it. A local-first or self-hosted client keeps those values where you can see them.
- Is an open-source API client as capable as Postman?
- For sending requests and running scripted collections in CI, yes. The picks here cover the daily work of building and checking an API. Postman has a larger marketplace of integrations and some polished team features, so weigh that if you depend on a specific add-on.
- Can I keep my API collections in Git?
- With the right client, yes, and it is the cleanest way to share them. A client that stores each request as a plain text file lets you commit the collection next to the code it tests and review changes in a pull request, with a clean way to roll back a mistake. That is a core reason to leave a cloud-only tool.
- Do I have to host anything to escape the vendor cloud?
- Not necessarily. One pick stores everything as local files with no server at all, so there is nothing to host. The other can run purely in your browser, and self-hosting is an option you reach for only when a team wants a shared instance on its own infrastructure.
- Will switching break my existing Postman collections?
- You will usually import them rather than lose them. Both clients here can bring in a Postman collection export, so your saved requests carry over. Expect to redo some environment setup by hand, since secrets do not travel in an export, which is the point.