Best API Design Tools in 2026
Updated
In short: Apidog is ranked #1 of 26 as of 4 October 2026, ahead of Microcks and Apollo Studio. The best-ranked option with a free plan is Microcks. The lowest first paid tier on this page is Apidog at $2.25/mo.
Planning an API means defining its contract and checking how changes fit the development workflow. Compared on AsyncAPI support, contract validation, free plan, Git synchronization, included team seats, mock server, OpenAPI support, paid from, and team collaboration, these tools offer useful dimensions for weighing specification and coordination needs. Apidog, Microcks, and Apollo Studio are among the available options. Consider which specifications your work relies on, whether contract validation and mock servers fit your process, and how Git synchronization or collaboration may support a team. Free-plan availability, included seats, and paid-from pricing add practical details to compare.
26 API design tools ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
16 of the 25 here have a free tier you can use, 0 have open-source code on record, and 0 have full bars: free, open, on most of your devices and documented.
| # | App | Signal | Free tier | Open code | Devices | From | Score |
|---|---|---|---|---|---|---|---|
| 1 | ApidogWeb · Windows · Mac · Linux · Self-hosted · API · Extension | Three bars | — | 4 of 6 | $2.25/mo | 6.7 | |
| 2 | MicrocksWeb · Windows · Mac · Linux · Self-hosted · API · Extension | Three bars | — | 4 of 6 | Free | 6.7 | |
| 3 | Apollo StudioWeb · Windows · Mac · Linux · Self-hosted · API | Three bars | — | 4 of 6 | $5/mo | 6.6 | |
| 4 | MockServerWeb · Windows · Mac · Linux · Self-hosted · API | Three bars | — | 4 of 6 | Free | 6.6 | |
| 5 | oasdiffWeb · Windows · Mac · Linux · Self-hosted · API | Three bars | — | 4 of 6 | $100/mo | 6.6 | |
| 6 | PactWindows · Mac · Linux · Self-hosted · API | Three bars | — | 3 of 6 | $115.42/mo | 6.6 | |
| 7 | PostmanWeb · Windows · Mac · Linux · Extension | Three bars | — | 4 of 6 | $9/mo | 6.6 | |
| 8 | TypeSpecWeb · Windows · Mac · Linux · Extension | Three bars | — | 4 of 6 | Free | 6.6 | |
| 9 | WireMockWeb · Windows · Mac · Linux · Self-hosted · API | Three bars | — | 4 of 6 | Free | 6.6 | |
| 10 | SchemathesisWindows · Mac · Linux · Self-hosted | Three bars | — | 3 of 6 | Free | 6.5 | |
| 11 | GraphQL HiveWeb · Self-hosted · API | Two bars | — | 1 of 6 | $20/mo | 6.4 | |
| 12 | OpenAPI StudioWeb · Self-hosted | Two bars | — | 1 of 6 | $9/mo | 6.4 | |
| 13 | PactFlowWeb · Self-hosted · API | Two bars | — | 1 of 6 | $115.42/mo | 6.4 | |
| 14 | Stoplight ElementsWeb · Self-hosted | Two bars | — | 1 of 6 | Free | 6.4 | |
| 15 | Swagger EditorWeb · Self-hosted | Two bars | — | 1 of 6 | Free | 6.4 | |
| 16 | SwaggerHubWeb · Self-hosted | Two bars | — | 1 of 6 | $61.67/mo | 6.4 | |
| 17 | MockoonWeb · Windows · Mac · Linux · Self-hosted · API | Two bars | — | — | 4 of 6 | €10/mo | 5.6 |
| 18 | RedoclyWeb · API · Extension | One bar | — | — | 1 of 6 | $10/mo | 5.5 |
| 19 | SmithyWindows · Mac · Linux | One bar | — | — | 3 of 6 | — | 5.2 |
| 20 | WSO2 API DesignerWeb · Windows · Mac · Linux · Extension | Two bars | — | — | 4 of 6 | $119/mo | 5.2 |
| 21 | vacuumWindows · Mac · Linux · Self-hosted · API · Extension | One bar | — | — | 3 of 6 | — | 5.1 |
| 22 | AssertibleWeb | No signal | — | — | 1 of 6 | — | 5.0 |
| 23 | AsyncAPI StudioWeb · Windows · Mac · Linux | One bar | — | — | 4 of 6 | — | 5.0 |
| 24 | Stoplight PrismWeb | No signal | — | — | 1 of 6 | — | 5.0 |
| 25 | MuleSoft ComposerWeb | One bar | — | — | 1 of 6 | $2,000/mo | 4.9 |
Is your app on this list?
Numbered spots on this list can be sponsored. They are labelled, and the editorial order and scores never change for payment.
Questions about this list
Which API design tool is ranked first on Freedom251?
Apidog is ranked #1 of 26 with a score of 6.7. Microcks is second and Apollo Studio third.
How many of these have a free plan?
16 of the 25 on this page publish a free plan on their own pricing pages.
Which is the cheapest paid option?
On this page, Apidog has the lowest first paid tier we found: $2.25/mo.
How is this list ranked?
Ranked free-and-open first: a usable free tier and open-source code, then the platforms it runs on and its documentation. Paid placements never change a rank.