How to slim api responses by filtering unwanted json keys
- Step 1Identify the fields your client actually uses — Review the mobile or integration code to find which fields are actually accessed. This is your keep list. Everything else is unnecessary payload.
- Step 2Paste the full API response — Paste the verbose JSON response. For paginated APIs, paste a representative page to see the full field set.
- Step 3Apply keep or remove filter — In keep mode, enter the field names to retain. In remove mode, enter the field names to drop. Use dot notation for nested fields (user.internalId) to target specific nested keys.
- Step 4Use the slimmed response as your BFF schema — Copy the slimmed output and use it as the target shape for your BFF transformation. The key list becomes the field whitelist in your server-side response transformer.
Frequently asked questions
How is this different from GraphQL field selection?+
GraphQL's selection set achieves the same goal at the query level — requesting only specific fields prevents them from being fetched and returned. This tool works post-response, which is useful when you cannot change the API (e.g. a third-party REST API) or when prototyping the right field set before implementing a GraphQL query.
Can I filter nested fields without affecting the parent object?+
Yes. Using dot notation, you can remove a specific nested field (user.internalToken) while keeping the rest of the user object intact. The parent object remains in the output with only the specified nested key removed.
Is the API response data — including any sensitive fields — uploaded to JAD Apps?+
No. All processing runs entirely in your browser. API response data including authentication tokens, internal IDs, and sensitive fields 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.