Multi-Chain Wallet Address Validator

EIP-55 defines a checksum encoding for Ethereum addresses. The checksum capitalizes specific letters in the hex address based on the keccak256 hash of the lowercase address. For example, '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045' has specific uppercase letters. Validating the checksum detects typos. All-lowercase or all-uppercase addresses are valid but skip checksum validation.

All EVM chains (Ethereum, Polygon, Arbitrum, Base, Optimism, BNB Chain) use the same 20-byte hex address format (0x prefix). The same private key generates the same address on all EVM chains. However, assets are not transferable between chains without bridges. Always verify you're on the correct network before sending.

Bitcoin has three address formats: P2PKH (starts with '1', legacy), P2SH (starts with '3', script hash), and Bech32/SegWit (starts with 'bc1', native SegWit). Bech32 addresses are lowercase, have lower fees due to smaller transaction size, and have better error detection. P2PKH is oldest and most widely supported.

Solana addresses are 32-byte Ed25519 public keys encoded in base58. They're 32-44 characters long and do not have a checksum in the address itself — validity is determined by successful decode of base58 and 32-byte length. Solana addresses are case-sensitive (unlike Ethereum checksums, there's no mixed-case encoding).

For Ethereum: use ethers.js `ethers.utils.isAddress()` or viem `isAddress()`. For Bitcoin: use `bitcoinjs-lib` or `@scure/btc-signer`. For Solana: use `@solana/web3.js` `PublicKey` constructor (throws if invalid). Always validate on both client and server. Never trust user-supplied addresses for gas estimation without validation.