Lesson 03 · Unit 6 · Solana
The transfer fee trap
The transfer fee extension skims a percentage of every transfer of the token — every buy, sell, and wallet-to-wallet move. Honest projects use fractions of a percent. The trap version launches at a friendly number and quietly raises it, or starts at 99% and relies on nobody checking.
What survives selling $1,000 worth, by fee
$999
0.1% fee
$950
5% fee
$500
50% fee
$10
99% fee
The tax that woke up
A Token-2022 launch ran for two days with a 1% transfer fee — plausible, even sympathetic ('funds the treasury'). Volume built. Then the fee authority, still held by the dev, scheduled it to 95%. He paid that fee too — there is no exempt path — but he also held the withdraw authority, so every cent of it came straight back to him.
Every later sell forfeited 95% to the fee vault the dev controlled. The pool was never pulled, the mint never touched — the entire rug was one config change on a legitimate extension.
What to check
Two facts, both public: the current fee, and who holds the fee-config authority. A fee that CAN be changed is a promise, not a property — same pen-holding question as every authority in chapter 4.
Where this goes next
The scanner surfaces this as one of a handful of trap signals — they are worth seeing together.