EVM Address Validator
Validate an EVM address: syntactic checks plus the EIP-55 checksum test (keccak-256 mixed-case). Returns the canonical checksummed form, flags addresses pasted with a broken checksum, and never guesses — an invalid checksum is an error, not a silent fix.
Worked examples
vitalik.eth address (checksummed)
GET /api/v1/crypto/address-validate?address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
Result: ✓ Valid EVM address — 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
All-lowercase (valid, not checksummed)
GET /api/v1/crypto/address-validate?address=0xd8da6bf26964af9d7eed9e03e53415d37aa96045
Result: ✓ Valid EVM address — 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045
Broken checksum
GET /api/v1/crypto/address-validate?address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96046
Result: ✗ Invalid EIP-55 checksum — should be 0xd8da6BF26964Af9d7EeD9E03e53415d37aa96046
Machine API (x402)
$0.002 / callThis tool is also a JSON API for AI agents. Requests without payment receive 402 Payment Required plus instructions; agents pay USDC on Base via the x402 protocol — no accounts, no API keys.
GET /api/v1/crypto/address-validate?address=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 HTTP/1.1
Host: agentstoolshub.com
→ 402 (payment required, instructions in headers)
→ 200 (after X-PAYMENT header; JSON body below)
{
"tool": "crypto/address-validate",
"input": {"address":"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"},
"result": { "value": 1, "answer": "✓ Valid EVM address — 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045" }
}Agent docs: /llms.txt · OpenAPI spec · integration guide
About this tool
Definitive EVM address validation: syntax check plus the EIP-55 checksum (keccak-256 of the lowercase hex, uppercasing matching nibbles). Uniform-case addresses are reported as such — valid but unchecksummed; mixed-case addresses must match the checksum exactly or the tool reports the correct canonical form.
EIP-55: keccak256(lowercase_hex40); uppercase the nibble if the corresponding hash nibble ≥ 8
Frequently asked questions
Why did a 'fine-looking' address fail?
Mixed-case addresses encode a checksum. One wrong character (or a typo that changes case) breaks the keccak-256 test — the failure is the feature that catches fat-finger errors.
Does this work for BTC or Solana addresses?
No — those use different encodings (Base58/Bech32 and ed25519 strings). This validator is for EVM chains: Ethereum, Base, Arbitrum, Optimism and every other EVM network (addresses are chain-agnostic).