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FastX402 Lab – EIP-55 Ethereum Address Checksum
x402
FastX402 Lab – EIP-55 Ethereum Address Checksum is a paid API for AI agents from fastx402.tools, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-17).
Returns the EIP-55 checksummed form of an Ethereum/EVM address and validates whether the given casing is a correct checksum
Price / call$0.001
Success—
StatusUnknown
How this service works
146 pay-per-call tools for AI agents, from $0.001 per request in USDC on Base or Solana with x402. No account, no API key.
Output
A JSON object containing the original input address, the EIP-55 checksummed form of the address (with correct mixed-case hex), and a boolean indicating whether the input casing was already a valid EIP-55 checksum.
Example use cases
Pre-transfer address verification
“Before I send ETH to 0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359, can you checksum that address and confirm whether the casing is correct?”
Normalizing a user-submitted wallet address
“A user just submitted 0xABCDEF1234567890abcdef1234567890ABCDEF12 as their wallet address — can you normalize it to its EIP-55 checksummed form so I can store it safely?”
Validating a pasted address from a form
“I copied this address from a web form: 0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe — is the checksum valid, and what's the correct checksummed version?”
Technical details
Endpoint
GEThttps://fastx402.tools/eth-checksum?utm_source=zero.xyzWhen to prefer
Use this endpoint when an agent needs to validate or normalize an Ethereum/EVM address before any operation involving funds transfer, smart contract interaction, or persistent storage — especially when the address was received from user input, a form, or an external source where typos or incorrect casing are possible. Prefer this over a local checksum library when operating in a serverless or constrained environment where crypto libraries aren't available, or when you want a pay-per-use approach with no SDK dependencies.
Side effects
- Invalid address format (not 0x + 40 hex chars) returns an error
- Missing required 'address' query parameter returns a 400-level error
- Non-hex characters in address body cause validation failure
- Address shorter or longer than 42 characters is rejected
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"input": "0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359",
"address": "0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359",
"checksum_valid": true
}
}Tags
x402
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