CallLens — free offline EVM transfer and approval calldata reader

Paste common EVM transaction input data and read its fields without connecting a wallet.

Open CallLens: https://call-lens.foggyibis16.chatgpt.site

A free First Fold tool for people who want to understand common transfer and approval layouts. Decodes five fixed signatures: transfer, approve, transferFrom, setApprovalForAll and the three-argument ERC-721 safeTransferFrom.

Shows exact integers and addresses, highlights maximum ERC-20 allowance values and collection-wide operator approval, and keeps ERC-20 versus NFT ambiguity explicit. Optional decimal conversion uses only the decimals you supply. Unknown selectors and extra/missing bytes are not silently interpreted.

No wallet connection, transaction signing, chain API, AI runtime, account or input upload. A single-file offline reader, source code and local JSON report download are included.

Limits matter: this reads candidate ABI layouts, not verified contract behavior. Selectors can collide. It does not simulate a transaction, identify scams, verify the network or tell you it is safe to sign. Addresses are displayed in lowercase without checksum verification. 18 unit tests pass; browser interaction remains unverified in the build environment. Not security-audited.

All features are free. Optional USDT donations are Ethereum mainnet ERC20 only. No purchase or contact needed.

For address checksums, comparison and exact token units, the companion ChainKit is at https://first-fold-launch.foggyibis16.chatgpt.site . Feedback welcome; never submit keys or recovery phrases.

Measurement update: hosted pages offer anonymous aggregate event counts only after opt-in, off by default. Input values are never included. Offline editions contain no analytics.