# Crypto QR Generator & Developer Tools > Free, open, browser-only tools for crypto payments and blockchain developers: payment QR code generators (BIP-21, EIP-681, Solana Pay, BOLT11), address validators and converters, exact unit converters, Keccak-256 / ABI / bech32 / hex utilities, raw transaction decoders for Ethereum, Bitcoin, Solana and Tron, and testnet batch-transfer tools. No sign-up, no server-side processing, nothing you enter is uploaded. Every page is a single HTML document with the tool at the top followed by an explanation, a how-to and an FAQ. Pages exist in English (default) and in 中文, Русский, Español, 日本語, 한국어, Português under /zh/, /ru/, /es/, /ja/, /ko/, /pt/. ## Payment QR code generators - [Crypto Payment QR Code Generator](https://crypto.xvvxvv.online/): Free crypto QR code generator for Bitcoin, Ethereum, USDT, USDC, Solana Pay and Lightning. Add an amount and label, download PNG or SVG. Runs in your browser. - [Bitcoin QR Code Generator](https://crypto.xvvxvv.online/bitcoin-qr-code-generator): Generate a Bitcoin QR code from your BTC address with an optional amount and label (BIP-21). Works with every Bitcoin wallet. Free, runs in your browser. - [Ethereum QR Code Generator](https://crypto.xvvxvv.online/ethereum-qr-code-generator): Generate an Ethereum QR code for your 0x address with an optional ETH amount (EIP-681). Works with MetaMask, Trust Wallet and Rainbow. Free, in your browser. - [USDT TRC-20 QR Code Generator](https://crypto.xvvxvv.online/usdt-trc20-qr-code-generator): Generate a USDT TRC-20 (Tron) QR code so customers can scan and pay from TronLink, Trust Wallet or any exchange. Free, no sign-up, nothing is uploaded. - [USDT ERC-20 QR Code Generator](https://crypto.xvvxvv.online/usdt-erc20-qr-code-generator): Generate a USDT ERC-20 QR code with an optional amount. Encodes an EIP-681 transfer request for the Tether contract on Ethereum. Free, runs in your browser. - [Solana Pay QR Code Generator](https://crypto.xvvxvv.online/solana-pay-qr-code-generator): Generate a Solana Pay QR code for SOL, USDC or USDT with an amount, label and message. Works with Phantom, Solflare and Backpack. Free, runs in your browser. - [Lightning QR Code Generator](https://crypto.xvvxvv.online/lightning-invoice-qr-code): Turn a Lightning invoice (lnbc...), LNURL or Lightning address (name@domain) into a scannable QR code. Free, generated in your browser, nothing uploaded. ## Address validators and converters - [Crypto Wallet Address Validator](https://crypto.xvvxvv.online/crypto-address-validator): Free crypto address validator: paste any wallet address to detect the network, verify the checksum and see the address type. Batch mode, runs in your browser. - [Bitcoin Address Validator](https://crypto.xvvxvv.online/bitcoin-address-validator): Validate a Bitcoin address instantly: legacy, P2SH, SegWit bc1q and Taproot bc1p. Verifies the checksum and detects testnet addresses. Free, in your browser. - [Ethereum Address Checksum (EIP-55) Converter](https://crypto.xvvxvv.online/ethereum-address-checksum): Convert any Ethereum address to its EIP-55 checksummed form and verify an existing checksum. Works for all EVM chains. Free, batch mode, runs in your browser. - [Tron Address Converter: Base58 ↔ Hex ↔ 0x](https://crypto.xvvxvv.online/tron-address-converter): Convert Tron addresses between the Base58 T… form, the 41… hex used by TronGrid and contracts, and the 0x EVM form. Checksum verified. Free, in your browser. - [Solana Address Validator](https://crypto.xvvxvv.online/solana-address-validator): Validate a Solana wallet address: checks the Base58 format and 32-byte length, and whether the key is on the ed25519 curve or a PDA. Free, runs in your browser. - [USDT Address Validator and Network Checker](https://crypto.xvvxvv.online/usdt-address-validator): Check a USDT address and find out which network it belongs to: ERC-20 (0x), TRC-20 (T…) or Solana. Verifies the checksum before you send. Free, in-browser. - [Bitcoin Cash Address Converter: CashAddr ↔ Legacy](https://crypto.xvvxvv.online/bitcoin-cash-address-converter): Convert Bitcoin Cash addresses between CashAddr (bitcoincash:q…) and legacy 1…/3… format. Checksum verified, hash160 and type shown. Free, in your browser. - [Cosmos Address Converter: Bech32 Prefix Changer](https://crypto.xvvxvv.online/cosmos-address-converter): Convert a Cosmos bech32 address to any other chain prefix: cosmos1, osmo1, juno1, celestia1, inj1, dydx1 and more. Verifies the checksum and shows the 0x bytes. - [Polkadot SS58 Address Converter: Public Key ↔ Any Prefix](https://crypto.xvvxvv.online/polkadot-ss58-address-converter): Decode a Polkadot, Kusama or Substrate SS58 address to its 32-byte public key, verify the BLAKE2b checksum and re-encode it for 17 network prefixes. Free. - [TON Address Converter: Raw ↔ Bounceable ↔ Non-Bounceable](https://crypto.xvvxvv.online/ton-address-converter): Convert TON addresses between raw 0:hex and user-friendly EQ…/UQ… forms, verify the CRC16 checksum and see testnet variants. Bounceable vs non-bounceable. ## Unit converters - [Ethereum Unit Converter: Wei ↔ Gwei ↔ Ether](https://crypto.xvvxvv.online/ethereum-unit-converter): Convert between wei, gwei, ether and every Ethereum unit instantly. Exact big-integer arithmetic with no floating-point rounding. Free, runs in your browser. - [Gwei to ETH Converter and Gas Fee Calculator](https://crypto.xvvxvv.online/gwei-to-eth-converter): Convert gwei to ETH and wei, and calculate an Ethereum gas fee from gas price and gas limit with an optional USD estimate. Exact, free, in your browser. - [Satoshi to Bitcoin Converter](https://crypto.xvvxvv.online/satoshi-to-bitcoin-converter): Convert satoshis to BTC and back, plus bits (μBTC) and millibitcoin. Exact 8-decimal arithmetic with no rounding. Free, instant, runs in your browser. - [Lamports to SOL Converter](https://crypto.xvvxvv.online/lamports-to-sol-converter): Convert lamports to SOL and SOL to lamports instantly. 1 SOL = 1,000,000,000 lamports. Exact integer arithmetic, no rounding, runs in your browser. - [Sun to TRX Converter](https://crypto.xvvxvv.online/sun-to-trx-converter): Convert sun to TRX and TRX to sun instantly. Tron's smallest unit explained, with energy and bandwidth fee examples. Exact, no rounding, free, in your browser. - [Token Decimals Converter](https://crypto.xvvxvv.online/token-decimals-converter): Convert raw token integers from contracts and APIs into human-readable amounts using the token's decimals, and back. USDT, USDC, WBTC presets. Free, in-browser. ## Developer tools - [Keccak-256 Hash Calculator](https://crypto.xvvxvv.online/keccak256-hash): Compute Keccak-256 (the Ethereum hash), SHA3-256 and SHA-256 of any text or hex bytes, plus the 4-byte function selector. Free, in your browser, no upload. - [Function Selector & Event Topic Calculator](https://crypto.xvvxvv.online/function-selector): Compute the 4-byte function selector and event topic hash from a Solidity signature, or look up a selector like 0xa9059cbb. Free, batch mode, in your browser. - [Ethereum ABI Encoder / Decoder](https://crypto.xvvxvv.online/abi-encoder-decoder): Encode Solidity arguments into calldata or decode calldata back into values from a function signature. Arrays, tuples, bytes and strings. Free, in your browser. - [Bech32 / Bech32m Encoder and Decoder](https://crypto.xvvxvv.online/bech32-encoder-decoder): Decode any bech32 or bech32m string (bc1 SegWit, Taproot, LNURL, npub) into its parts, or encode a witness program. BIP-173 and BIP-350. Free, in your browser. - [Hex ↔ Decimal Converter for Big Numbers](https://crypto.xvvxvv.online/hex-to-decimal-converter): Convert hex to decimal and back for numbers of any size, with binary, bytes32 padding and int256 two's complement for EVM work. Free, runs in your browser. - [Crypto Signature Verifier](https://crypto.xvvxvv.online/signature-verifier): Verify crypto signatures in your browser: recover the Ethereum signer of personal_sign or EIP-712 typed data, check Solana ed25519 and Bitcoin signed messages. - [Ethereum Event Log Decoder](https://crypto.xvvxvv.online/event-log-decoder): Decode Ethereum event logs in your browser: paste a log, receipt or topics and data to get the event name and parameters. ERC-20, ERC-721, Uniswap, custom ABI. ## Raw transaction decoders - [Raw Transaction Decoder](https://crypto.xvvxvv.online/transaction-decoder): Paste a raw signed or unsigned transaction and see from, to, value, fee, nonce, calldata and signatures. EVM, Bitcoin, Solana and Tron. Free, in your browser. - [Ethereum Raw Transaction Decoder](https://crypto.xvvxvv.online/ethereum-transaction-decoder): Decode a raw Ethereum transaction (RLP hex): recover the sender, see to, value, nonce, gas, EIP-1559 fees, chain ID and calldata. Types 0–4. Free, in-browser. - [Bitcoin Raw Transaction Decoder](https://crypto.xvvxvv.online/bitcoin-transaction-decoder): Decode a raw Bitcoin transaction or PSBT in your browser: txid, inputs and outputs with addresses and amounts, script types, size, vsize, weight and RBF. Free. - [Solana Transaction Decoder](https://crypto.xvvxvv.online/solana-transaction-decoder): Decode a serialized Solana transaction (base64, base58 or hex): fee payer, signatures, accounts and every instruction, with Token and System calls named. Free. - [Tron Transaction Decoder](https://crypto.xvvxvv.online/tron-transaction-decoder): Decode a Tron transaction from raw_data_hex, signed hex or TronGrid JSON: txID, recovered signer, fee limit, TRX and TRC-20 transfers. Free, in your browser. ## Batch transfer (testnets only) - [Batch Transfer / Multisend (Testnets)](https://crypto.xvvxvv.online/batch-transfer): Send ETH, ERC-20, SOL, SPL, TRX or TRC-20 tokens to many addresses in a few signed transactions. Non-custodial, free, runs in your browser. Testnets only. - [EVM Batch Transfer (Sepolia and other testnets)](https://crypto.xvvxvv.online/evm-batch-transfer): Multisend for Ethereum testnets: send ETH or any ERC-20 token to hundreds of addresses in one transaction with MetaMask. Sepolia and more. Non-custodial, free. - [Solana Batch Transfer (devnet)](https://crypto.xvvxvv.online/solana-batch-transfer): Airdrop or multisend on Solana devnet: send SOL, SPL or Token-2022 tokens to many addresses with Phantom, Solflare or Backpack. Non-custodial, free, no server. - [Tron Batch Transfer (Nile / Shasta testnets)](https://crypto.xvvxvv.online/tron-batch-transfer): Multisend for Tron testnets: send TRX or any TRC-20 token to hundreds of addresses per transaction with TronLink on Nile or Shasta. Non-custodial, free. ## Site - [About this site](https://crypto.xvvxvv.online/about): Why this free crypto QR code generator and developer toolbox exists, how it works entirely in your browser, and who builds and maintains it. - [Privacy policy](https://crypto.xvvxvv.online/privacy): Privacy policy: addresses, transactions and data you enter are processed in your browser and never uploaded. Details on server logs, cookies and advertising. - [Contact](https://crypto.xvvxvv.online/contact): Report a bug, suggest a feature, request another chain or ask about mainnet batch transfers. Email the developer of this free crypto toolbox.