Setting REACT_APP_DEFINITION_URL / REACT_APP_DEFINITION_FILE at build time has no effect

Author: antoineaugerCreated Feb 10, 2026Updated Feb 20, 2026

The REACT_APP_DEFINITION_URL / REACT_APP_DEFINITION_FILE variables documented here have no effect / are not used within the codebase.

Local steps to reproduce:

 $ REACT_APP_DEFINITION_URL=https://raw.githubusercontent.com/readmeio/oas-examples/refs/heads/main/3.1/yaml/train-travel.yaml npm run build:app
 $ docker build . -f Dockerfile.unprivileged -t swaggerapi/swagger-editor:latest-unprivileged
 $ docker run -d -p 8080:8080 swaggerapi/swagger-editor:latest-unprivileged

Then, visit http://localhost:8080 (clear the cache + app storage for the domain).

Observe that the AsyncAPI260StreetlightsYAML specification is always loaded - no matter the REACT_APP_DEFINITION_URL value.

Source: swagger-api/swagger-editor

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