How to repair malformed json configuration files
- Step 1Paste the malformed config file content — Copy the full configuration file content — package.json, tsconfig.json, .eslintrc.json, appsettings.json, or any other JSON config — and paste it into the fixer.
- Step 2Review the detected issues — The fixer reports detected issues: trailing commas, comments, single-quoted strings, duplicate keys. Review the list to confirm the fixes are appropriate for your config.
- Step 3Apply the fixed output — Copy the fixed JSON and paste it back into the configuration file. The application should now parse the config without errors.
- Step 4Consider using JSONC for config files with comments — If you need comments in configuration files, use JSONC (JSON with Comments) — supported by VS Code's tsconfig.json, .eslintrc.json, and devcontainer.json. Configure your parser to use JSONC: import { parse } from 'jsonc-parser' instead of JSON.parse.
Frequently asked questions
Can JSON config files have comments?+
Standard JSON does not allow comments. However, some configuration formats use JSONC (JSON with Comments), which allows // line comments and /* */ block comments. VS Code supports JSONC for settings.json, tsconfig.json, and other configuration files. Standard JSON parsers (JSON.parse) will fail on JSONC — use the jsonc-parser package for JSONC files.
How do I find and fix duplicate keys in a JSON config file?+
The format fixer detects duplicate keys and reports them. JSON parsers handle duplicate keys differently: most use the last value, some throw errors. To fix: identify which value is correct and remove the duplicate key entirely.
Are the config file contents transmitted to JAD Apps?+
No. Format fixing runs entirely in your browser. Configuration file contents with private settings are never transmitted to JAD Apps servers.
Privacy first
Conversion runs locally in your browser. No file is uploaded — only metadata counters are saved for signed-in dashboard stats.