Lesson 5 — Your First Trade — A Swap You Can See, Prove, and Close

Swap, mirror, revoke — one loop you can trust

Ava doesn’t promise profit. She promises a loop.

“We’ll do this once,” she says, laying a sticky note beside your keyboard. “Small, visible, complete. You’ll open a door, you’ll see yourself in the mirror, and you’ll close the window you opened. That’s a trade.”

You already crossed the ferry and installed the door. Today you teach your hands a rhythm you can repeat at size without shaking.

Act I — The plan you can say out loud

You open your bookmarked dapp—the official page of a major DEX. No search. No ads. Plain page. Good.

“We start with ETH → USDC,” Ava says. “It spends ETH—no approval yet—and gives us a little USDC so we can show approvals on purpose next.”

She reads the sticky note with you:

• Amount: coffee-money (€5–€10)
• Slippage: 0.5%
• Network: Ethereum (ERC-20)
• Expect gas: a few euro — the toll

“Say it.” You do. The room gets simpler.

Connect wallet. Rabby shows a simulation; MetaMask/Trust expand details on click. You confirm.

Ava taps the explorer bookmark. “Let the chain speak.”

The transaction appears pending, then turns Success. You open it:

• From: your address
• To: DEX router
• Tokens: ETH out, USDC in

You copy the Txn Hash under today’s date. Nothing dramatic—just a receipt no one can quietly edit. Your shoulders drop a few millimeters.

“Good,” Ava says. “That was motion without a window. Now we’ll open one on purpose—and close it.”

Act II — Opening (then closing) a window

You now hold a little USDC. To spend an ERC-20, you must approve a contract to move it on your behalf. That approval is a window.

Back on the DEX, flip the direction: USDC → ETH, tiny size. The interface asks to Approve USDC.

“Read it,” Ava says. “Who gets what power?”

The prompt shows the spender (router/permit contract) and an amount. If the dapp offers approve exact or custom amount, you choose the tiny swap size—not unlimited. If only unlimited is offered, you whisper to the notebook: we’ll revoke right after.

Approve. On the explorer, a separate transaction appears (approve, Allowance > 0).
Swap. A second transaction follows—the actual trade.

You copy both hashes beneath the first—proof stacked in a neat column.

“Door opened, door used,” Ava says. “Now close it.”

Open your revoke tool (official page, from bookmarks). Connect. The list shows USDC → [DEX Router]. You click Revoke. Your wallet asks; you confirm. A small click in the UI, the entry blinks—then vanishes. On the explorer, one last transaction sets Allowance = 0.

Silence, like a window settling into its frame.

“That quiet you feel,” Ava says, “is posture.”

Desktop, phone, same loop

On desktop, Rabby’s simulation keeps you from blind-signing; MetaMask’s details expand when you ask.
On phone, Trust/Rabby Mobile confirm with Face/biometric; the explorer app sits one tap away. The mirror doesn’t care about screens—only history.

What almost went wrong (and why it didn’t)

A cheaper chain winked in the dropdown; you said E-R-C-20 out loud and ignored it.
The DEX defaulted to unlimited approval; you chose exact (or revoked immediately after).
The UI flashed “Completed” early; you waited for Success on the explorer before touching anything else.
A look-alike “Un1swap” tab lurked in search; your official bookmark kept you out.

Every time, the mirror and your notes kept you honest.

The feel of a finished loop

You look at the page: three lines of proof (swap 1, approve, swap 2) and a final revoke. The explorer tabs sit like receipts in a drawer. Nothing wobbles.

Your pulse stays level. You’re not guessing. You’re done.

Ava’s smile is small. “You didn’t chase. You executed. That’s the difference between clicking and trading.”

Anchors to carry

• Plan → Swap tiny → Mirror → Revoke → Breathe. (One loop, end to end.)
• Explorer is the receipt. Screenshots are decoration.
• Approvals are windows. Open exactly what you need; close them when you’re done.

Ava closes the notebook.

“You’ve done a full on-chain loop,” she says. “Next course, we take these calm hands into weather—and keep them steady.”