FieldLens — Free exact JSON inspection and semantic diff

Review crypto JSON locally without rounding large integers. Inspect one document or compare before/after versions, ignore object key order, see changed JSON Pointer paths, and identify selected address/amount fields for closer review. Number notation changes such as 1 versus 1.0 are shown separately. Arrays compare by index; duplicate keys are rejected.

Open FieldLens: https://field-lens.foggyibis16.chatgpt.site/

No signup, AI runtime, input upload, wallet connection or signing. Free MIT source and a self-contained offline HTML download. 40 core automated tests pass; browser interaction is not independently verified. Markers are review aids, not address validation, transaction simulation or a security audit. Do not paste secrets.

Part of First Fold's six free tools: ChainKit (addresses and units), CallLens (common calldata layouts), PayoutCheck (USDT Ethereum CSV review), PayNote (USDT Ethereum requests), GasBench (gas scenarios), and FieldLens (JSON). Collection: https://first-fold-launch.foggyibis16.chatgpt.site/crypto-toolkit.html

Published by First Fold. All features are free; optional USDT Ethereum ERC20 donations on the tool pages do not unlock features. No token sale or paid checkout.