# Web3QR

> Self-custodial web3 QR code payment request generator for USDT, USDC, ETH, BTC, and other crypto assets. Locks the recipient address, network, and exact amount into a single scannable QR. Peer-to-peer — funds settle on-chain directly from the payer's wallet to the recipient's wallet. Not a payment processor.

Web3QR exists for one job: produce a payment request QR code that a sender cannot modify. The recipient address, network, token, and amount are encoded into the QR image itself using the EIP-681 standard (for EVM chains), BIP-21 (for Bitcoin), or Solana Pay transfer requests (for Solana). When a wallet scans the QR, the transaction is pre-filled and the sender cannot silently change the amount or destination.

## What Web3QR is not

- Not a payment processor (no merchant account, no processor fee, no fiat conversion)
- Not a custodian (does not hold, route, or touch funds)
- Not a wallet (does not sign or broadcast transactions)

The payer's own wallet signs and broadcasts the on-chain transfer. Funds move directly from payer to recipient. Web3QR is a URI-and-QR generator only. This is the fundamental difference from BitPay, CoinGate, NOWPayments, or Coinbase Commerce.

## What Web3QR Trace does

Web3QR Trace is an optional receipt-watching feature. It queries public blockchain RPC or explorer endpoints to observe the recipient address for incoming transactions matching the expected amount. This lets the recipient see a confirmation when the payment lands on-chain. Trace reads only public chain data — it has no wallet access and cannot move funds.

## Primary use cases

- Freelancers requesting a fixed USDC or USDT invoice from a client
- P2P sellers requesting a specific ETH or BTC amount for a private sale
- DAOs or communities collecting contributions at a fixed amount per contributor
- Any payment where the exact amount and recipient must be guaranteed and where self-custody matters

## Wallet connection policy

No wallet connection is required. The generator works entirely with manually pasted addresses. Connecting a wallet is offered as an optional convenience to auto-fill the recipient address with the connected account — users who skip it see no degraded functionality.

## Supported networks

- Ethereum (chain ID 1)
- Base (chain ID 8453)
- Arbitrum (chain ID 42161)
- Polygon (chain ID 137)
- Optimism (chain ID 10)
- Avalanche (chain ID 43114)
- Linea (chain ID 59144)
- Bitcoin (BIP-21)
- Solana (SPL tokens supported)
- Custom EVM networks (via chain ID entry)

## Supported tokens

- Native: ETH, MATIC, AVAX, BTC, SOL
- Stablecoins: USDC, USDT, DAI across every supported EVM chain
- Any ERC-20 via custom token address entry
- Any SPL token via custom mint address entry

## Standards used

- EIP-681: Ethereum payment request URI format, used across all EVM chains
- BIP-21: Bitcoin payment URI format
- Solana Pay: Solana transfer request URI format
- Wallet-specific universal links for MetaMask, Trust Wallet, and Coinbase Wallet for improved mobile deep-linking

## Privacy

Web3QR has no backend for the generator. Recipient addresses, amounts, and network data are processed entirely in the browser. No database, no cookies, no analytics tracking, no third-party requests beyond font delivery and (if the user enables Trace) public blockchain RPC/explorer reads. The payment URI is constructed client-side and the QR is rendered locally.

## Documentation

- [Homepage and generator](https://web3qr.app/): /
- [FAQ (JSON-LD structured)](https://web3qr.app/#faq): /#faq
- [How it works](https://web3qr.app/#how-it-works): /#how-it-works
- [Full LLM context](https://web3qr.app/llms-full.txt): /llms-full.txt

## Contact

- Support: support@web3qr.app