Send Crypto by Username or Claim Link: How It Works

Sending crypto by username or claim link replaces a 42-character address with something human-friendly. A username resolves to a wallet, while a claim link locks funds in a contract until the recipient collects them or the sender cancels. Both reduce typing errors, but neither can undo a mistake after a successful claim.

Why addresses cause trouble

A raw address is long, unreadable and unforgiving: one wrong character can send funds somewhere nobody controls, and there is no support desk. The Bitcoin.one whitepaper names unreadable addresses as one of its four obstacles. Usernames, QR codes and links are the app’s answer, alongside plain addresses for people who prefer them.

The four ways to send, as the paper describes them

Method	How it works	Main risk
@username	Resolves to a wallet in the app	Picking the wrong or lookalike name
Address	Paste a wallet address	Typos, wrong network
QR code	Scan the recipient’s code	Scanning a swapped or malicious code
Claim link	Funds locked against a one-time link key	Link leaks before claim

How claim links work

For BC1, the paper says the amount is locked in the PayRouter contract against a one-time link key. The recipient uses the link to collect it. Links expire after at most 90 days, and if no one claims, the sender can cancel and recover the funds. The PayRouter fee is 0, with a hard ceiling of 1% written into the contract.

This design handles a common problem: sending money to someone who does not have a wallet yet. They open the link, sign up (the app uses an email or Google login, as we describe in ERC-4337 smart wallets without a seed phrase), and collect.

Key takeaway: a claim link is a bearer instrument. Whoever holds it can claim, so share it only through a channel you trust and cancel it if it goes astray.

Security habits for links

1. Send the link privately, not in public channels.
2. Tell the recipient to claim promptly.
3. If the link may have leaked and is unclaimed, cancel it from the sending account.
4. Confirm receipt with the person through a separate channel.
5. Avoid large amounts until you have tested with a small one.

The “cancel and recover” feature protects against an unclaimed link, but not against one that someone else has already claimed.

Fees: what is and is not free

Per the paper, BC1 P2P sends and claim links cost nothing at the app level, BTC sends are a plain transfer, and the project’s home page says no app fee applies to sends while noting network gas can apply. The shop is where the 2% margin lives, as we describe in buying gift cards with crypto. One thing the project’s materials do not explain is how its economics work if sends remain free and shop margin is the main revenue source; that is a fair thing to watch over time.

Username risks

Usernames are convenient but create lookalike risk: names that differ by one letter, or that impersonate someone you know. Verify the exact spelling with the recipient. The paper does not describe a username dispute or recovery process, and we do not assume there is one.

Which network, which asset

Sending BTC and BC1 are different operations. The paper describes native BTC held as WBTC on BOB, withdrawable back to Bitcoin, and BC1 as a token with versions on Ethereum, BOB, Base and Solana. If you send to an external address, confirm that it expects the right asset on the right chain. Our Layer 2 explainer covers why wrapped and native assets differ.

Comparing with other options

Sending by address is universal but error-prone. Usernames and links are friendlier but depend on the app’s infrastructure. Exchanges often offer internal transfers by email, but that is custodial. Each choice trades convenience against control, and none is best for every case.

What to know about testnet and risk

The app runs on the BOB Sepolia testnet with test tokens today, so sending now is a rehearsal. The risk disclosure reminds users that transactions cannot be reversed and that third-party services can fail. Treat the app as early software until mainnet, which the paper targets for Q1 2027, a date that may change.

This is general education, not financial advice.

Step-by-step: sending to someone with no wallet

Here is the flow the paper describes, with the checks worth making at each step.

1. Choose BC1 or BTC and enter the amount. Start small the first time.
2. Choose “claim link” as the delivery method.
3. The app locks the BC1 in the PayRouter contract against a one-time link key.
4. Copy the link and send it privately.
5. The recipient opens it, signs up with email or Google, and collects.
6. If nobody claims, cancel within 90 days to recover the funds.

Two details matter. First, the link is the key, so treat it like cash in an envelope. Second, expiry is a maximum of 90 days, so the recipient should not wait.

What can go wrong, and what to do

Problem	Likely cause	What to do
Recipient cannot open link	Link truncated by a messaging app	Resend through another channel
Link claimed by the wrong person	Link leaked	Nothing can be reversed after a claim; use private channels
Funds not showing	Network delay or wrong chain	Check the transaction on the explorer
Wrong username	Typo or lookalike	Verify the exact name before sending

Because the app is on a test network today, none of this involves real value yet, which makes it a good time to practise. Try the whole flow with test tokens, including cancellation, so you know how it feels before mainnet. Details of the app are on the project’s app page.

Etiquette and safety for recipients

If someone sends you a link, check the source before clicking: scammers send fake “claim your tokens” links. Open links only from people you know and expect, and never connect a wallet that holds significant funds to an unfamiliar site. Remember the project’s own warning that transactions cannot be reversed.