Running npm start in the Swagger UI repo fails on Node 20+ with this error:

TypeError: require(...) is not a function
at [eval]:1:16

This happens because the open package is now ESM-only, and using it via require() in a CommonJS script is no longer supported.

Problematic script is
In the current package.json, the script is:

"open-static": "node -e "require('open')('http://localhost:3002')\""
This fails on modern Node versions.

Fix:
Replace the script with a more compatible version using npx:

"open-static": "npx open-cli http://localhost:3002"

Above line is included in package.json , Now swagger-ui is starting on node 20+ versions also

And optionally add open-cli as a dev dependency:

npm install --save-dev open-cli
Note: npx will work even without installing open-cli locally, but for CI/stability, it’s better to include it in devDependencies.