SigLens

SigLens is a browser extension for EVM selector/signature workflows.

It helps you quickly move between raw calldata/selectors and human-readable signatures without leaving your explorer or dev flow.

What it does

• Lookup: 0xa9059cbb -> candidate function signatures (with provider fallback + cache)
• Hash: transfer(address,uint256) -> selector, event signature -> topic hash
• Interface Parser: Solidity function declarations -> canonical signatures + selectors
• Decode (best effort): calldata + selected candidate signature -> decoded argument table
• Explorer Enhancement: hover raw selectors on explorer pages to resolve likely signatures

Explorer support

Content script enhancements are currently enabled for:

• etherscan.io (+ common Etherscan-family explorers)
• blockscout.com

Use Settings to enable/disable explorer enhancement.

Important accuracy note

Selector lookup and calldata decode are best-effort based on public signature databases (Sourcify 4byte + 4byte.directory).

• Results are candidates, not guaranteed verified ABI truth.
• Selector collisions are possible and surfaced in UI.

Stack

• WXT
• React + TypeScript (strict)
• Zod validation
• Vitest tests

Project structure

• src/entrypoints/
  • background.ts shared orchestration + messaging
  • popup/ main UI
  • options/ settings UI
  • explorer-enhancer.content.ts explorer page augmentation
• src/features/ domain use-cases
• src/infrastructure/ API/storage/cache/messaging
• src/test/ unit tests

Local development

Requirements

• Node.js 20+
• pnpm 10+

Install

pnpm install

Run in dev mode

pnpm dev

Build extension

pnpm build

Load unpacked from:

• .output/chrome-mv3

Scripts

pnpm dev
pnpm build
pnpm zip
pnpm lint
pnpm typecheck
pnpm test

Current milestone status

• Milestone 0: bootstrap/skeleton ✅
• Milestone 1: local hashing ✅
• Milestone 2: selector lookup + provider fallback + cache ✅
• Milestone 3: interface parser ✅
• Milestone 4: history + settings ✅
• Milestone 5: calldata decode (best effort) ✅
• Milestone 6: explorer enhancement (Etherscan + Blockscout) ✅

Contributing

Issues and PRs are welcome.

When contributing:

• keep business logic out of React components
• keep APIs typed and validated
• run pnpm lint && pnpm typecheck && pnpm test before submitting

Security and privacy

• No account required
• No analytics included by default
• Lookup/history data stored locally in extension storage

Changelog

See CHANGELOG.md.