React .env Example and Validator
React apps often rely on build-time environment variables. The important question is which values end up in the browser.
Use Cases
- Clean up a Create React App or Vite React .env file
- Prepare environment examples for onboarding
- Spot values that should move to a backend
Workflow
- 1Paste the environment file used by your React build.
- 2Review public prefixes and risky values.
- 3Generate a safer example file for your repository.
Practical Tips
- Treat frontend environment variables as public unless proven otherwise.
- Proxy private API calls through a server.
- Use clear placeholder values in .env.example files.
Common Questions
Can a React app hide API keys?
A browser-only React app cannot reliably hide secrets. Private keys should stay on a server.
Does this tool upload my file?
No. Validation happens in the browser.