01 Start
Overview
Oopsend is the undo button for sends on Robinhood Chain. What it is, the problem it fixes, and the numbers that matter.
#The problem
On-chain transfers are final the moment they land. A wrong address, a wrong amount, a friend who never opens the wallet you sent to: the money is gone, or stuck in a place nobody controls. Wallets add warnings, but a transfer itself has never had a window where it can still be reversed.
#What Oopsend does
Oopsend turns a send into a claim link backed by an escrow contract.
- You lock ETH or any ERC-20 in the contract and get a link.
- You share the link by message, chat, tweet or QR code.
- The recipient opens it and claims to any wallet. Anyone can submit the claim for them, so the claim never has to come from the recipient's own wallet. Until the public relayer runs, the recipient or a friend submits it and pays a fraction of a cent of gas.
- Until the claim lands, you can undo and get 100% back. If nobody claims before the expiry, anyone can trigger the refund and it returns to you.
The window is the whole product. Before the claim the send is reversible. After the claim it is final, exactly like a normal transfer.
#The numbers
| Fee | 0.3%, only when a link is claimed. Locked into each link when it is created |
| Fee ceiling | 1%, hard-coded in the contract |
| Undo and expiry | free, you get 100% back (you only pay network gas) |
| Undo window | you choose, from 10 minutes to 90 days |
| Per-link cap | 2 ETH for ETH links, 1% of total supply for token links (the admin can change both for new links, and cannot touch open ones) |
| Chain | Robinhood Chain, id 4663 |
| Contract | Oopsend.sol at 0x7B530e91D9dc24C78Ca2eEE2B494E7dE1B680AC0, 6,101 bytes of runtime code, no proxy, no upgrade hook |
#Where funds can go
Funds leave an escrow in exactly three ways, and there is no fourth.
| Exit | Who triggers it | Where the money goes |
|---|---|---|
claim | anyone, with the link's signature | the recipient named in the signature (net), and the fee accrual |
undo | the sender only | back to the sender, in full |
expireRefund | anyone, after expiry | back to the sender, in full |
The admin can tune the fee (up to 1%), the caps, and pause new links. There is no admin withdrawal and pausing never blocks undo, refund or claim. Read Security and limits for what that does and does not protect against.
#$OOPS
Claim fees accrue inside the contract. Anyone can call sweepFees to move them to the public fee wallet, which buys back and burns $OOPS. The token launches on Pons with no presale and no team allocation. See Fees and token.
#Try it
The lab runs the same rules in your browser: create a link, undo it, claim it as a friend, then attack it as a stranger. Keys, signatures and revert selectors are real. The ledger is local, so nothing moves money.
#Where to go next
- How it works: every flow, step by step, with the state machine.
- Quickstart: create, undo and claim a link from a script.
- Contract reference: every function, event and error.
- Security and limits: the trust model, and what Oopsend cannot do.