Frequently asked questions
Is OASForge free?
Yes. The editor, validator, mock server, converters and exporters are all free to use, with no account and no usage limits. The source code is available on GitHub under the Elastic License 2.0.
Does my API spec leave my browser?
No. There is no backend: documents, version history and settings are stored in your browser’s local storage, and the mock server answers requests inside the page. The only network requests are ones you ask for, such as “Load URL” or the live Petstore view.
Which OpenAPI versions are supported?
Swagger 2.0 (with a one-click converter to OpenAPI 3), OpenAPI 3.0.x, 3.1.x and 3.2.x. Validation is version-aware: each document is checked against the keys and rules of its own declared version.
Can I use OASForge offline?
Yes, two ways. The site is an installable PWA that precaches itself and works fully offline after the first visit. There is also standalone.html — the entire app in one file that runs from a double-click, with no web server.
Can I import a Postman collection?
Yes. Open a Postman Collection v2 / v2.1 export via “Open file” or “Load URL” and it is converted to OpenAPI 3.0.3 automatically — auth schemes mapped, saved responses preserved as named examples, transport headers cleaned up.
How is this different from Swagger Editor?
OASForge adds a native dark theme, a stateful in-browser mock server, one-click quick fixes, a structure insert menu, Postman import, local version history with diff, and full offline support — while keeping the familiar code-plus-preview layout.
Can I use it commercially?
Yes — internal tools, client work and embedding are all allowed under the Elastic License 2.0. What is not allowed is offering OASForge itself to third parties as a hosted or managed service, removing the notices, or circumventing license keys.
Who builds OASForge?
OASForge — formerly Swagger Dark UI — is designed, built and maintained by Kaan Dikeç as an independent open-source project.
No signup, no install — the editor runs entirely in your browser.
Open the OASForge editor