Best Free API Testing Tools in 2026
API clients used to be simple desktop apps you installed and forgot about. Then they became platforms with accounts, clouds and seats, and the free tier acquired limits nobody expected from a tool that sends HTTP requests.
Postman's free plan now covers one user, 10,000 API calls a month and 50 AI credits. For a tool many developers open twenty times a day, that is a meaningful ceiling, and it is the reason a wave of alternatives exists.
Here is what each free tier gives you, checked August 2026.
Quick comparison
| Tool | Free tier | Paid entry | Rating | Reviews |
|---|---|---|---|---|
| Hoppscotch | Open source, self-hostable | Cloud tiers available | 4.9 | 77 |
| Insomnia | Essentials free, unlimited local and cloud projects | Paid tiers above | 4.3 | 15 |
| Postman | 1 user, 10,000 calls/mo, 50 AI credits | $9/mo (Solo, annual) | 4.6 | 2,311 |
| Apidog | Free tier | Team plans | not rated | - |
Ratings aggregated by Toolradar across G2 and Capterra.
The ratings say something the pricing does not
Hoppscotch aggregates to 4.9, the highest score in this comparison, from 77 reviews. Postman sits at 4.6 from 2,311.
The sample sizes are not comparable and the scores should not be read as a ranking. What they do show is a pattern we see repeatedly: the open-source alternative in a category where the incumbent tightened its free tier attracts an unusually enthusiastic user base. People who moved to Hoppscotch chose it deliberately, often after being annoyed by something, and they rate accordingly.
Postman's 4.6 across two thousand reviews is the more informative number, and it is a good score. The frustration in this category is not with the product, which remains the most capable here; it is with what happened to the free plan of a tool people originally installed as a utility.
Insomnia's 4.3 from 15 reviews is too thin to weigh at all, which is worth stating because it is the tool we recommend most for people leaving Postman.
Hoppscotch: open source and genuinely unlimited
Aggregated rating 4.9 across 77 reviews, the highest here. Hoppscotch is open source and free to self-host, with cloud and enterprise tiers available.
It runs in the browser with no install, and if you want it entirely inside your network you deploy it yourself. For teams testing internal APIs that are not reachable from a vendor's cloud, that is not a preference, it is the requirement.
It covers REST, GraphQL and WebSockets, and it is fast in a way the heavier platforms are not, because it is a tool rather than a workspace.
What you give up is the collaboration layer: shared workspaces, request history across a team, mock servers. If those matter, you are back in platform territory.
Insomnia: unlimited projects on the free tier
Aggregated rating 4.3, from only 15 reviews. Insomnia's Essentials plan is free with unlimited local and cloud projects, and Git Sync for a limited number of users.
Insomnia's free tier is the most generous among the platform-shaped tools, and the reason is positioning: it competes directly with Postman by not doing what Postman did to its free plan.
The interface is calmer, the app is lighter, and it handles the same protocols. For a developer who wants a good client without a platform, this is the pragmatic choice.
Git Sync is the interesting feature: collections stored in your repository rather than a vendor's cloud, so they are reviewed and versioned like code.
Postman: the incumbent, and the tightest free tier
Aggregated rating 4.6 across 2,311 reviews (4.6 on G2, 4.7 on Capterra), the only robust sample here. Postman's free plan covers one user, 10,000 API calls a month and 50 AI credits, with Solo at $9 a month billed annually.
Postman is still the most capable tool here and the one everyone recognises. Mock servers, monitors, contract testing, documentation generation and a collection format that has become a de facto standard for sharing an API.
The free tier is where the pressure sits. Ten thousand calls a month is roughly 300 a day, which sounds generous until a test collection with fifty requests runs on every change.
At $9, Solo is not expensive. The complaint is not the price, it is that a tool people installed as a utility became a subscription.
Apidog: design, test and document together
Apidog has a free tier with paid team plans.
Apidog's pitch is consolidation: API design, testing, mocking and documentation in one place, so the spec and the tests do not drift apart. Teams currently juggling a spec file, a Postman collection and a separate docs site are the audience.
For an individual poking at endpoints it is more tool than necessary. For a team that owns an API contract, having one artefact rather than three is a real reduction in work.
What free API tools cost you
Your secrets go where the tool goes. Cloud-synced collections often carry tokens, keys and production credentials in environment variables. On a free tier with cloud sync on by default, those leave your machine. This is the single most common accident in this category, and it is why self-hosted Hoppscotch and Git-synced Insomnia collections appeal to security-conscious teams.
Call limits count more than you think. A collection run counts every request. Automated runs in CI multiply that quickly, and Postman's 10,000 monthly calls is easy to exhaust without any human clicking anything.
Collections are a lock-in surface. Years of accumulated requests, environments and scripts are real work. Postman's format exports and imports widely, which is worth confirming for whatever you choose, because it is the thing that decides whether leaving is a day or a quarter.
Manual testing is the part that does not scale
Every tool here is excellent at the thing developers actually do with them, which is poke an endpoint by hand and read the response. That is genuinely useful and it is also where most teams stop, which is the real gap.
The step nobody takes is turning the collection into something that runs without a human. All four support it, through a command-line runner or a CI integration, and the difference it makes is categorical: a request you send by hand tests the API on the day you were curious, while a collection running on every deploy tests it continuously.
There is a cost, and it is the one that catches Postman users. Automated runs consume call allowances fast, because a fifty-request collection running on every commit is fifty calls a commit. Against a 10,000-a-month free ceiling, that is a few hundred commits, which is a busy fortnight.
The practical arrangement most teams land on is to keep exploratory testing in whichever client they like and run the automated suite from the command line, where there is no per-call meter at all. That splits the tool from the pipeline and stops the pricing model dictating how often you test.
If you take one thing from this comparison beyond the free tiers, take that: the client is for exploring, the runner is for verifying, and conflating them is what makes the limits hurt.
How to choose
If your APIs are internal or your team is security-conscious, Hoppscotch self-hosted, which is the only option here with no vendor in the path.
If you want a capable free client without a platform, Insomnia Essentials, whose unlimited projects make it the most generous free tier here.
If you need mocks, monitors and shared documentation, Postman, and budget the $9 Solo plan because the free tier is not designed for daily use.
If you own an API contract as a team, Apidog, which keeps the spec and the tests as one artefact.
Whatever you choose, get secrets out of synced collections on day one. Use environment variables pulled from your own secret store rather than typed into a cloud-synced field, and the rest of the decision becomes reversible.
Related: our guide to free API clients covers the same ground from the client side, and the Dupple reviews directory has current pricing.
FAQ
Is Postman still free?
There is a free plan, but it is narrow: one user, 10,000 API calls a month and 50 AI credits. Solo starts at $9 a month billed annually. For a tool used daily, most people either upgrade or move to Insomnia or Hoppscotch.
What is the best free alternative to Postman?
Insomnia if you want a similar experience with a more generous free tier, including unlimited local and cloud projects. Hoppscotch if you want open source, browser-based, and the option to self-host so nothing leaves your network.
Can I self-host an API testing tool?
Hoppscotch is designed for it and is the cleanest option. That matters most for internal APIs that a vendor's cloud cannot reach, and for teams who do not want request history and credentials sitting in someone else's infrastructure.
Do API clients store my credentials safely?
They store them, and where they store them is the question. Cloud-synced environments carry your tokens to the vendor's servers by design. Keep production secrets out of synced collections and pull them from your own secret store instead, whichever tool you use.
Which API testing tool is rated highest?
Hoppscotch, at 4.9 aggregated across 77 reviews, though Postman's 4.6 across 2,311 is the more reliable figure. The pattern is common in categories where an incumbent tightened its free tier: the open-source alternative attracts users who chose it deliberately and rate it enthusiastically.
Is Postman's rating hurt by its pricing?
Its 4.6 is a good score, so not in any obvious way. The frustration in this category is about a utility becoming a subscription rather than about the product failing, and Postman remains the most capable tool here. Ratings capture whether software does its job; they are poor at capturing resentment about a pricing model.
