Unit 2 · Level 1 · Reading transactions
Review: name that transaction
You can now identify the four big species in the wild: plain transfers (empty input data), approvals (spending permissions, watch for unlimited ones), swaps (router call, token flows in the logs), and NFT mints, burns, and sales (watch the zero address and the payment leg). Time for a spot-check safari.
Free to play. No ads, no token, no account needed to start.
What you get asked
Name that transaction from one clue
One glance at the To, the method, and the logs, and you've classified most transactions before reading a single number.
You find an old unlimited approval to a dapp you stopped using in 2023. What's the risk of leaving it?
Approvals never expire on their own, and history is full of old contracts getting exploited years later. Revoke what you don't use.
To see what a swap actually delivered, read the transaction's ___, not its Value field.
The Transfer events in the logs are the ground truth of every token that moved: in, out, and every hop between.
An influencer claims their NFT 'just sold for 50 ETH'. How would a chain reader verify it?
And check who the buyer was: a 'record sale' to the seller's own second wallet is wash trading, not a sale.
What's the common thread across everything in this unit?
'Don't trust, verify' stops being a slogan once you can do it yourself. You now can: swaps, approvals, mints and all. 🐜
The rest of this unit
Transfers, approvals, swaps, mints: learn what each really looks like.