What am I about to sign?
What am I about to sign? Pre-sign calldata decoder for Base: data=0x.. (selector+args) [&to=0x.. token/contract for symbol+decimals] or hash=0x.. (decode an existing tx). Resolves the 4-byte selector (builtin + openchain + 4byte, collision-checked by ABI round-trip), returns function signature, typed args, plain-English summary, risk none|low|medium|high, flags (unlimited_approval, unknown_spender, approve_all_nfts, offchain_permit, permit2_allowance, batched_calls, inner_approval,...
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
GET https://kr-x402-mvp.kgy5612.workers.dev/crypto/decode-calldata
| Category | Market data |
|---|---|
| Provider host | kr-x402-mvp.kgy5612.workers.dev |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 1 from 1 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-10-31 | valid payment request | 402 | $0.002 | 28 ms |
Example input (from the provider)
{
"method": "GET",
"queryParams": {
"data": "0x095ea7b3000000000000000000000000000000000022d473030f116ddee9f6b43ac78ba3ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
"to": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
},
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"additionalProperties": false,
"properties": {
"data": {
"description": "Calldata hex (selector + ABI args). Required unless hash given",
"examples": [
"0x095ea7b3000000000000000000000000000000000022d473030f116ddee9f6b43ac78ba3ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
],
"pattern": "^0x[0-9a-fA-F]{8,}$",
"type": "string"
},
"hash": {
"description": "Optional Base tx hash: decode its input instead of data",
"pattern": "^0x[0-9a-fA-F]{64}$",
"type": "string"
},
"to": {
"description": "Optional target contract (token) for symbol/decimals + label",
"pattern": "^0x[0-9a-fA-F]{40}$",
"type": "string"
}
},
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}