Lesson 11 — Approvals and Revokes: Power You Lend and Take Back

Every open window is a promise. Every revoke is its return.

The explorer still shows your calm green checkmark from yesterday — proof that motion can end in order.
But Ava doesn’t move on.
She waits, pencil in hand, watching you notice the faint code line that still remembers your address.

“See that?” she says quietly. “The trade ended. But the permission didn’t.”
She flips to a clean page, two shapes already forming — You and Contract.
“This is the window we open next,” she says. “And the one we’ll learn to close.”

Act II — Opening (Then Closing) a Window

The first swap sits complete on your explorer — proof that motion can end in calm.
Ava doesn’t move to the next task.
She waits until you notice something quiet on the screen.

The balance changed, but something else didn’t: a line of code in the background still remembers you.

“That memory,” she says, “is an approval.
It’s the permission you gave the contract to move tokens on your behalf.
Every ERC-20 token works this way: it asks, ‘May I move this amount from you to somewhere else?’
And until you answer ‘no,’ the answer stays ‘yes.’”

She draws two shapes in your notebook — one labeled You, the other Contract.
Between them: an arrow.

“Approvals are what make DeFi possible,” she says.
“They’re not danger; they’re delegation.
But delegation without awareness becomes dependency.”

Understanding the Concept

“Most traders think they own their tokens,” Ava continues, “but on-chain, what they actually own is the right to approve who moves them.
That right is power — quiet, invisible power.
And power is safest when it’s explicit.”

She taps the table once.
“Every approval is a small act of trust wrapped in code.
It isn’t evil. It’s just leverage.
If you leave too many open, you’ve spread your leverage thin.”

You start to see the pattern: nothing in the chain truly vanishes.
Everything granted stays granted until you revoke it.

Opening One — Deliberately

You flip the swap direction on your DEX: USDC → ETH.
The interface pauses, asking for Approve USDC.

Ava doesn’t tell you to click.
She asks: “Who gets what power — and for how long?”

You check the spender address, the token, the amount.

“This contract,” she explains, “is a router — a piece of infrastructure that temporarily holds permission so it can exchange on your behalf.
But routers don’t forget.
Until you take the permission back, it stays theirs.”

She points to the field marked Unlimited Approval.
“Convenience always asks for infinity.
Discipline sets a boundary.”

You type a small amount, confirm, and watch the explorer.
A new transaction appears — Allowance > 0.

“Good,” Ava says.
“That’s the sound of trust expressed with context.
You opened a window on purpose — and you know its size.”

Why Windows Exist

She lets you look at the two transactions — the swap and the approval — and says:
“The blockchain can’t read intention.
It only reads permissions.
So we build these windows to say, for this task, I allow this action.
When the job’s done, we close the window ourselves.”

She leans back, thoughtful.
“Centralized systems hide this from you — their windows never close because they want you to forget they’re open.
Self-custody is different.
You’re the one who decides when the light comes in.”

Closing the Window

You open revoke.cash from your bookmarks.
The interface feels familiar — minimal, almost sterile.

“This,” Ava says, “is where you reclaim the power you lent out.”

You connect your wallet; the list appears.
Each line shows a contract you once trusted.
You find USDC → DEX Router, click Revoke, and confirm the small gas fee.

The explorer refreshes: Allowance = 0.

“That,” she says softly, “is sovereignty returning home.
Nothing dramatic, just code agreeing that you decide when it stops.”

Reflection

Ava turns your notebook around and writes two sentences in the margin:
Approvals make flow possible.
Revokes make ownership real.

“Every open door in crypto is a line of code that trusts you to remember it exists,” she says.
“You just practiced remembering.”

The room feels different — not silent like before, but balanced.
The explorer shows four neat proofs: Swap 1 – Approve – Swap 2 – Revoke.
The system holds its history; you hold the keys.

Ava watches you breathe once, slow and even.
“That’s the sound of control,” she says.
“Not resistance — alignment.
Now you know what power feels like when it listens.”

Mistakes That Didn’t Happen

Ava flips back a few pages and circles four words: cheap network, infinite approval, early click, fake page.
“These,” she says, “are the traps you already walked past without noticing.”

She closes the notebook halfway.
“Next, we’ll slow time down and study what almost went wrong — because prevention is proof too.”