Kertivo Check: payment verify
Payment verification for x402: verify a USDC transaction on Base — did this payment really settle, and did it pay the right address the right amount? Send a tx hash (or x402 authorization): confirmations, real-USDC transfer check, expectedPayTo/expectedAmount match, fake-USDC and lookalike-address warnings, who funded the payer (external, self_funded, unknown), plain-English summary and a receipt. Body {txHash|authorization, expectedPayTo?, expectedAmount?}. Free demo: POST /demo.
OtherLiveeip155:8453Exactvia cdp
Payment-verificationx402BaseUsdcSettlement
Calls · 30d
3
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 14 snapshots so far.
$2.66
Verified settled volume
92 settlements proven x402 by their on-chain EIP-3009 marker.
$0.010
Listed price
As published in the catalog. Always read the live 402 before paying.
3
Calls · 30d
Upstream's own call count for this endpoint, not ours.
2
Unique payers · 30d
Last called 2026-10-16 22:41Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x509E55c4F898B43C856Fb0E51048B1b7bFBC9eDEThe wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"error": "Payment required. Free fixture demo: POST /demo — same shape as paid /check on a fixed real Base USDC tx ($0). This route is $0.01 USDC, charged only on HTTP 200.",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x509E55c4F898B43C856Fb0E51048B1b7bFBC9eDE",
"amount": "10000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
],
"resource": {
"url": "https://kertivo.com/check",
"tags": [
"payment-verification",
"x402",
"base",
"usdc",
"settlement"
],
"mimeType": "application/json",
"description": "Payment verification for x402: verify a USDC transaction on Base — did this payment really settle, and did it pay the right address the right amount? Send a tx hash (or x402 authorization): confirmations, real-USDC transfer check, expectedPayTo/expectedAmount match, fake-USDC and lookalike-address warnings, who funded the payer (external, self_funded, unknown), plain-English summary and a receipt. Body {txHash|authorization, expectedPayTo?, expectedAmount?}. Free demo: POST /demo.",
"serviceName": "Kertivo Check: payment verify"
},
"extensions": {
"bazaar": {
"info": {
"input": {
"body": {
"txHash": "0xc37cbdfa44230f05129348d5160254abf354791d79de68228b201ba09de143c1",
"expectedPayTo": "0x509E55c4F898B43C856Fb0E51048B1b7bFBC9eDE",
"expectedAmount": "1"
},
"type": "http",
"method": "POST",
"bodyType": "json"
},
"output": {
"type": "json",
"example": {
"mode": "live_paid",
"block": 52409752,
"found": true,
"match": {
"ok": true,
"payToMatch": true,
"amountMatch": true
},
"funding": {
"verdict": "external",
"scannedBlocks": {
"to": 52409752,
"from": 52360000,
"complete": false,
"stoppedEarly": "enough recent funding found"
}
},
"payment": {
"to": "0x509e55c4f898b43c856fb0e51048b1b7bfbc9ede",
"from": "0xfc1e390266f3b29179b5d63a7937a689d1e5279a",
"amount": "1"
},
"receipt": {
"reason": null,
"verdict": "external",
"rpcCalls": 9,
"priceCharged": "0.01 USDC",
"blocksScanned": {
"to": 52409752,
"from": 52360000,
"complete": false
}
},
"summary": "1 USDC from 0xfc1e… to 0x509e… at block 52409752. Matches expected payment. Payer was funded externally.",
"warnings": [],
"confirmed": true,
"confirmations": 1200
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"bodyType",
"body"
],
"properties": {
"body": {
"type": "object",
"properties": {
"token": {
"type": "string",
"description": "Optional (aliases asset, currency): \"USDC\" or the Base USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (apexfaucet-style). Any other token is a 400 unsupported_token, not charged. Responses always echo token \"USDC\"."
},
"txHash": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{64}$",
"description": "Base mainnet transaction hash"
},
"minAmount": {
"type": [
"string",
"number"
],
"description": "Optional floor (aliases min_amount, min): payment must be at least this many USDC; unlike expectedAmount it is not exact"
},
"authorization": {
"type": "object",
"required": [
"from",
"nonce"
],
"properties": {
"from": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$"
},
"nonce": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{64}$"
},
"validAfter": {
"type": [
"string",
"integer"
]
},
"validBefore": {
"type": [
"string",
"integer"
],
"description": "unix seconds"
}
},
"description": "Optional EIP-3009 authorization (x402 exact payload) to check when there is no tx or the tx is not found"
},
"expectedPayTo": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$",
"description": "Expected recipient (full-address, case-insensitive compare)"
},
"expectedPayer": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$",
"description": "Optional expected payer (aliases from, payer): the USDC Transfer's from must equal it"
},
"selfAddresses": {
"type": "array",
"items": {
"type": "string"
},
"maxItems": 10,
"description": "Optional: other addresses you control; funding from them counts as self_funded"
},
"expectedAmount": {
"type": [
"string",
"number"
],
"description": "Expected USDC amount, decimal (e.g. \"0.01\")"
}
},
"description": "Provide txHash, or authorization (EIP-3009) when you have no tx hash, or both."
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object",
"required": [
"found",
"summary",
"mode",
"receipt"
],
"properties": {
"mode": {
"enum": [
"live_paid",
"demo"
],
"type": "string"
},
"block": {
"type": [
"integer",
"null"
]
},
"found": {
"type": "boolean"
},
"match": {
"type": [
"object",
"null"
],
"properties": {
"ok": {
"type": "boolean"
},
"payToMatch": {
"type": [
"boolean",
"null"
]
},
"payerMatch": {
"type": [
"boolean",
"null"
],
"description": "only when expectedPayer given"
},
"amountMatch": {
"type": [
"boolean",
"null"
]
},
"minAmountMatch": {
"type": [
"boolean",
"null"
],
"description": "only when minAmount given"
}
}
},
"status": {
"type": [
"string",
"null"
]
},
"funding": {
"type": [
"object",
"null"
],
"properties": {
"reason": {
"enum": [
"no_inbound_in_window",
"scan_incomplete"
],
"type": "string",
"description": "Only present when verdict=unknown"
},
"verdict": {
"enum": [
"external",
"self_funded",
"unknown"
],
"type": "string"
},
"topFunders": {
"type": "array"
},
"scannedBlocks": {
"type": "object",
"properties": {
"to": {
"type": "integer"
},
"from": {
"type": "integer"
},
"complete": {
"type": "boolean"
}
}
},
"payeeFundedPayer": {
"type": "boolean"
}
}
},
"payment": {
"type": [
"object",
"null"
],
"properties": {
"to": {
"type": "string"
},
"from": {
"type": "string"
},
"amount": {
"type": "string"
}
}
},
"receipt": {
"type": "object",
"required": [
"blocksScanned",
"rpcCalls",
"priceCharged",
"verdict",
"reason"
],
"properties": {
"reason": {
"enum": [
"no_inbound_in_window",
"scan_incomplete",
null
],
"type": [
"string",
"null"
]
},
"verdict": {
"enum": [
"external",
"self_funded",
"unknown",
null
],
"type": [
"string",
"null"
]
},
"rpcCalls": {
"type": "integer"
},
"priceCharged": {
"type": "string",
"description": "'0.01 USDC' on /check, '0' on /demo"
},
"blocksScanned": {
"type": [
"object",
"null"
],
"properties": {
"to": {
"type": "integer"
},
"from": {
"type": "integer"
},
"complete": {
"type": "boolean"
}
}
}
}
},
"summary": {
"type": "string"
},
"warnings": {
"type": "array",
"items": {
"type": "object",
"properties": {
"code": {
"enum": [
"fake_token",
"lookalike_address",
"tx_reverted",
"no_usdc_transfer",
"zero_value_transfer",
"bridged_usdbc"
],
"type": "string"
},
"message": {
"type": "string"
}
}
}
},
"confirmed": {
"type": "boolean"
},
"timestamp": {
"type": [
"string",
"null"
]
},
"settlement": {
"type": "object",
"properties": {
"note": {
"type": "string",
"description": "For settled: delivery/response by the seller cannot be verified on-chain"
},
"reason": {
"enum": [
"confirmed_onchain",
"pending_confirmation",
"authorization_used",
"tx_not_found",
"tx_reverted",
"no_usdc_transfer",
"zero_value_transfer",
"authorization_unused",
"authorization_unused_or_expired",
"authorization_unused_pending"
],
"type": "string"
},
"verdict": {
"enum": [
"settled",
"not_settled"
],
"type": "string"
}
},
"description": "Added field: did the payment settle on-chain?"
},
"attestation": {
"type": "object",
"description": "Signed response (EIP-191 by the key at /.well-known/attestation, not a wallet) over sha256 of this body minus attestation; present when signing is enabled"
},
"authorization": {
"type": "object",
"description": "Present when authorization was given: {from, nonce, used, chainTime, validBefore, expired}"
},
"confirmations": {
"type": "integer"
},
"ignoredFields": {
"type": "array",
"items": {
"type": "string"
},
"description": "Request fields Kertivo Check did not use (they did not affect the answer); only present when there were any"
},
"usdcTransfers": {
"type": "array",
"items": {
"type": "object",
"properties": {
"to": {
"type": "string"
},
"from": {
"type": "string"
},
"amount": {
"type": "string"
}
}
}
}
}
}
}
}
}
}
}
},
"x402Version": 2
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.01USDC≈ $0.01 USD
on Base · exact scheme
Pay 0.01 USDC on Base to 0x509E…C9eDE. The signed payment is good for 5 minutes.
- Paid to
- 0x509E…C9eDE
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 10000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x509E55c4F898B43C856Fb0E51048B1b7bFBC9eDE",
"amount": "10000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"body": {
"txHash": "0xc37cbdfa44230f05129348d5160254abf354791d79de68228b201ba09de143c1",
"expectedPayTo": "0x509E55c4F898B43C856Fb0E51048B1b7bFBC9eDE",
"expectedAmount": "1"
},
"type": "http",
"method": "POST",
"bodyType": "json"
},
"output": {
"type": "json",
"example": {
"mode": "live_paid",
"block": 52409752,
"found": true,
"match": {
"ok": true,
"payToMatch": true,
"amountMatch": true
},
"funding": {
"verdict": "external",
"scannedBlocks": {
"to": 52409752,
"from": 52360000,
"complete": false,
"stoppedEarly": "enough recent funding found"
}
},
"payment": {
"to": "0x509e55c4f898b43c856fb0e51048b1b7bfbc9ede",
"from": "0xfc1e390266f3b29179b5d63a7937a689d1e5279a",
"amount": "1"
},
"receipt": {
"reason": null,
"verdict": "external",
"rpcCalls": 9,
"priceCharged": "0.01 USDC",
"blocksScanned": {
"to": 52409752,
"from": 52360000,
"complete": false
}
},
"summary": "1 USDC from 0xfc1e… to 0x509e… at block 52409752. Matches expected payment. Payer was funded externally.",
"warnings": [],
"confirmed": true,
"confirmations": 1200
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"bodyType",
"body"
],
"properties": {
"body": {
"type": "object",
"properties": {
"token": {
"type": "string",
"description": "Optional (aliases asset, currency): \"USDC\" or the Base USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (apexfaucet-style). Any other token is a 400 unsupported_token, not charged. Responses always echo token \"USDC\"."
},
"txHash": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{64}$",
"description": "Base mainnet transaction hash"
},
"minAmount": {
"type": [
"string",
"number"
],
"description": "Optional floor (aliases min_amount, min): payment must be at least this many USDC; unlike expectedAmount it is not exact"
},
"authorization": {
"type": "object",
"required": [
"from",
"nonce"
],
"properties": {
"from": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$"
},
"nonce": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{64}$"
},
"validAfter": {
"type": [
"string",
"integer"
]
},
"validBefore": {
"type": [
"string",
"integer"
],
"description": "unix seconds"
}
},
"description": "Optional EIP-3009 authorization (x402 exact payload) to check when there is no tx or the tx is not found"
},
"expectedPayTo": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$",
"description": "Expected recipient (full-address, case-insensitive compare)"
},
"expectedPayer": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$",
"description": "Optional expected payer (aliases from, payer): the USDC Transfer's from must equal it"
},
"selfAddresses": {
"type": "array",
"items": {
"type": "string"
},
"maxItems": 10,
"description": "Optional: other addresses you control; funding from them counts as self_funded"
},
"expectedAmount": {
"type": [
"string",
"number"
],
"description": "Expected USDC amount, decimal (e.g. \"0.01\")"
}
},
"description": "Provide txHash, or authorization (EIP-3009) when you have no tx hash, or both."
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object",
"required": [
"found",
"summary",
"mode",
"receipt"
],
"properties": {
"mode": {
"enum": [
"live_paid",
"demo"
],
"type": "string"
},
"block": {
"type": [
"integer",
"null"
]
},
"found": {
"type": "boolean"
},
"match": {
"type": [
"object",
"null"
],
"properties": {
"ok": {
"type": "boolean"
},
"payToMatch": {
"type": [
"boolean",
"null"
]
},
"payerMatch": {
"type": [
"boolean",
"null"
],
"description": "only when expectedPayer given"
},
"amountMatch": {
"type": [
"boolean",
"null"
]
},
"minAmountMatch": {
"type": [
"boolean",
"null"
],
"description": "only when minAmount given"
}
}
},
"status": {
"type": [
"string",
"null"
]
},
"funding": {
"type": [
"object",
"null"
],
"properties": {
"reason": {
"enum": [
"no_inbound_in_window",
"scan_incomplete"
],
"type": "string",
"description": "Only present when verdict=unknown"
},
"verdict": {
"enum": [
"external",
"self_funded",
"unknown"
],
"type": "string"
},
"topFunders": {
"type": "array"
},
"scannedBlocks": {
"type": "object",
"properties": {
"to": {
"type": "integer"
},
"from": {
"type": "integer"
},
"complete": {
"type": "boolean"
}
}
},
"payeeFundedPayer": {
"type": "boolean"
}
}
},
"payment": {
"type": [
"object",
"null"
],
"properties": {
"to": {
"type": "string"
},
"from": {
"type": "string"
},
"amount": {
"type": "string"
}
}
},
"receipt": {
"type": "object",
"required": [
"blocksScanned",
"rpcCalls",
"priceCharged",
"verdict",
"reason"
],
"properties": {
"reason": {
"enum": [
"no_inbound_in_window",
"scan_incomplete",
null
],
"type": [
"string",
"null"
]
},
"verdict": {
"enum": [
"external",
"self_funded",
"unknown",
null
],
"type": [
"string",
"null"
]
},
"rpcCalls": {
"type": "integer"
},
"priceCharged": {
"type": "string",
"description": "'0.01 USDC' on /check, '0' on /demo"
},
"blocksScanned": {
"type": [
"object",
"null"
],
"properties": {
"to": {
"type": "integer"
},
"from": {
"type": "integer"
},
"complete": {
"type": "boolean"
}
}
}
}
},
"summary": {
"type": "string"
},
"warnings": {
"type": "array",
"items": {
"type": "object",
"properties": {
"code": {
"enum": [
"fake_token",
"lookalike_address",
"tx_reverted",
"no_usdc_transfer",
"zero_value_transfer",
"bridged_usdbc",
"amount_looks_atomic"
],
"type": "string"
},
"message": {
"type": "string"
}
}
}
},
"confirmed": {
"type": "boolean"
},
"timestamp": {
"type": [
"string",
"null"
]
},
"settlement": {
"type": "object",
"properties": {
"note": {
"type": "string",
"description": "For settled: delivery/response by the seller cannot be verified on-chain"
},
"reason": {
"enum": [
"confirmed_onchain",
"pending_confirmation",
"authorization_used",
"tx_not_found",
"tx_reverted",
"no_usdc_transfer",
"zero_value_transfer",
"authorization_unused",
"authorization_unused_or_expired",
"authorization_unused_pending"
],
"type": "string"
},
"verdict": {
"enum": [
"settled",
"not_settled"
],
"type": "string"
}
},
"description": "Added field: did the payment settle on-chain?"
},
"attestation": {
"type": "object",
"description": "Signed response (EIP-191 by the key at /.well-known/attestation, not a wallet) over sha256 of this body minus attestation; present when signing is enabled"
},
"authorization": {
"type": "object",
"description": "Present when authorization was given: {from, nonce, used, chainTime, validBefore, expired}"
},
"confirmations": {
"type": "integer"
},
"ignoredFields": {
"type": "array",
"items": {
"type": "string"
},
"description": "Request fields Kertivo Check did not use (they did not affect the answer); only present when there were any"
},
"usdcTransfers": {
"type": "array",
"items": {
"type": "object",
"properties": {
"to": {
"type": "string"
},
"from": {
"type": "string"
},
"amount": {
"type": "string"
}
}
}
}
}
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-10-16 22:41Z
- Last indexed by Roundhouse
- 2026-10-26 14:50Z
- Last enriched (probe, favicon, geo)
- 2026-10-16 17:16Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 14 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
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Using Roundhouse, look up the x402 service Kertivo Check: payment verify and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Kertivo%20Check%3A%20payment%20verify' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://kertivo.com/check, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.