Contract Diff
Compare two verified contracts across every source file.
Reads public data
Paste two contract addresses to compare. A match is about the source — not clearance to use either contract.
About contract diff
Fork a well-known contract, change three lines, and it will look entirely legitimate to anyone who does not read it closely. This compares two verified contracts across every source file the explorer returns — not just the entry file — and says whether they are the same code, with comments and whitespace ignored. A match is about the source, not clearance to use either contract. The comparison that answers something is an unfamiliar contract against the original it claims to be, or a new implementation against the version already audited.
Common questions
Why compare two verified contracts?
Upgrades, forks and same-token-on-another-chain claims are where silent differences hide. Diffing every source file shows what changed — or that nothing did — without trusting a marketing screenshot.
Do both contracts need to be verified?
Yes for a source-level diff. Without verification there is no author-published text to compare; bytecode-only comparison is a different problem and is not what this page claims to solve.
Does a clean diff mean an upgrade is safe?
No. Identical source can still be administered by a key that can rug; different source can be a harmless bugfix. The diff is evidence about code changes, not about who controls the proxy admin.