B20 Check
Legitimacy check for B20 tokens on Base. Verifies whether an address is a factory-native B20, detects copycats and known-asset imposters (homoglyph-aware), reports live issuer powers (mint, burn, pause, freeze, seize, admin) and issuer activity, and returns a danger/caution/ok verdict as an EIP-712-signed attestation an agent can independently verify.
OtherLiveeip155:8453Exactvia cdp
B20BaseToken-verificationSecurityAttestation
Activity
—
Nothing indexed for this service or its provider yet. Not a claim that it is unused — only that we hold no record.
$0.08
Verified settled volume
8 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.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-07-11 12:49Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x26B57af5022250F01497F3e19dd537d01d124BA1The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
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 0x26B5…24BA1. The signed payment is good for 5 minutes.
- Paid to
- 0x26B5…24BA1
- 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": "0x26B57af5022250F01497F3e19dd537d01d124BA1",
"amount": "10000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"pathParams": {
"address": "0xb2000000000000000000001fd821494127f35af0"
},
"queryParams": {}
},
"output": {
"type": "json",
"example": {
"flags": [
{
"code": "VIA_LAUNCHER",
"detail": "Created through an intermediary launcher contract, not a direct factory call.",
"severity": "info"
}
],
"isB20": true,
"address": "0xb200000000000000000000f52267Ce6274432c30",
"network": "mainnet",
"variant": "asset",
"verdict": "ok",
"creation": {
"block": 48380900,
"params": {
"name": "Example Token",
"symbol": "EXTKN",
"variant": "asset",
"currency": null,
"decimals": 18
},
"txHash": "0x9a67ce…",
"creator": null,
"launcher": "0x77132d…",
"txOrigin": "0x52c8ff…",
"timestamp": 1783491000,
"viaLauncher": true
},
"attestation": {
"domain": {
"name": "B20 Check Attestation",
"chainId": 8453,
"version": "1",
"verifyingContract": "0xb200000000000000000000f52267Ce6274432c30"
},
"signed": true,
"signer": "0x1388d1e3751512955A53C7c2795Eaf8a3B029e6A",
"issuedAt": 1783670000,
"expiresAt": 1783670600,
"signature": "0x8f2a…",
"pinnedBlock": 48443612,
"attestationId": "0x3e7197…"
},
"issuerPowers": {
"canBurn": false,
"canMint": false,
"canPause": false,
"canSeize": false,
"canFreeze": false,
"supplyCap": "1000000000000000000000000000",
"adminActive": false,
"supplyCapKnown": true,
"freezeConfigured": false,
"transferRestrictions": false
},
"issuerActivity": {
"burns": 0,
"memos": 0,
"mints": 1,
"pauses": 0,
"freezes": 0,
"seizures": 0,
"roleChanges": 0,
"lastActionBlock": 48380900
}
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method"
],
"properties": {
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"pathParams": {
"type": "object",
"required": [
"address"
],
"properties": {
"address": {
"type": "string",
"pattern": "^0x[0-9a-fA-F]{40}$",
"description": "EVM address of the token to verify (B20 addresses start with 0xb20…; any address is accepted)."
}
},
"additionalProperties": false
},
"queryParams": {
"type": "object",
"properties": {}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object",
"title": "VerifyResult",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"example": {
"flags": [
{
"code": "VIA_LAUNCHER",
"detail": "Created through an intermediary launcher contract, not a direct factory call.",
"severity": "info"
}
],
"isB20": true,
"address": "0xb200000000000000000000f52267Ce6274432c30",
"network": "mainnet",
"variant": "asset",
"verdict": "ok",
"creation": {
"block": 48380900,
"params": {
"name": "Example Token",
"symbol": "EXTKN",
"variant": "asset",
"currency": null,
"decimals": 18
},
"txHash": "0x9a67ce…",
"creator": null,
"launcher": "0x77132d…",
"txOrigin": "0x52c8ff…",
"timestamp": 1783491000,
"viaLauncher": true
},
"attestation": {
"domain": {
"name": "B20 Check Attestation",
"chainId": 8453,
"version": "1",
"verifyingContract": "0xb200000000000000000000f52267Ce6274432c30"
},
"signed": true,
"signer": "0x1388d1e3751512955A53C7c2795Eaf8a3B029e6A",
"issuedAt": 1783670000,
"expiresAt": 1783670600,
"signature": "0x8f2a…",
"pinnedBlock": 48443612,
"attestationId": "0x3e7197…"
},
"issuerPowers": {
"canBurn": false,
"canMint": false,
"canPause": false,
"canSeize": false,
"canFreeze": false,
"supplyCap": "1000000000000000000000000000",
"adminActive": false,
"supplyCapKnown": true,
"freezeConfigured": false,
"transferRestrictions": false
},
"issuerActivity": {
"burns": 0,
"memos": 0,
"mints": 1,
"pauses": 0,
"freezes": 0,
"seizures": 0,
"roleChanges": 0,
"lastActionBlock": 48380900
}
},
"required": [
"address",
"network",
"isB20",
"verdict",
"flags",
"attestation"
],
"properties": {
"flags": {
"type": "array",
"items": {
"type": "object",
"properties": {
"code": {
"type": "string"
},
"detail": {
"type": "string"
},
"severity": {
"enum": [
"info",
"low",
"medium",
"high"
],
"type": "string"
}
}
},
"description": "Risk flags."
},
"isB20": {
"type": "boolean",
"description": "True only for a factory-native B20 token."
},
"address": {
"type": "string",
"description": "Checksummed EVM address inspected."
},
"network": {
"enum": [
"mainnet",
"sepolia"
],
"type": "string"
},
"variant": {
"enum": [
"asset",
"stablecoin",
null
],
"type": [
"string",
"null"
]
},
"verdict": {
"enum": [
"ok",
"caution",
"danger"
],
"type": "string"
},
"creation": {
"type": [
"object",
"null"
],
"description": "Creation tx/block/creator and decoded create params (null if not a native B20)."
},
"attestation": {
"type": "object",
"properties": {
"domain": {
"type": "object"
},
"signed": {
"type": "boolean"
},
"signer": {
"type": [
"string",
"null"
]
},
"issuedAt": {
"type": "integer"
},
"expiresAt": {
"type": "integer"
},
"signature": {
"type": [
"string",
"null"
]
},
"pinnedBlock": {
"type": "integer"
},
"attestationId": {
"type": "string"
}
},
"description": "EIP-712 attestation. attestationId is a deterministic content id (always present, but NOT an integrity proof on its own); integrity requires signed=true and recovering signer from signature."
},
"issuerPowers": {
"type": [
"object",
"null"
],
"description": "Current issuer capabilities: canMint, canBurn, canPause, canFreeze, canSeize, adminActive, supplyCap, transferRestrictions."
},
"issuerActivity": {
"type": [
"object",
"null"
],
"description": "Observed on-chain issuer actions: mints, burns, freezes, seizures, pauses, memos, roleChanges, lastActionBlock."
}
},
"description": "Signed B20 legitimacy attestation for a single address on Base."
}
}
}
}
},
"routeTemplate": "/v1/verify/:address"
}
}Provenance
- Seen in the source catalog
- 2026-07-11 12:49Z
- Last indexed by Roundhouse
- 2026-08-04 03:20Z
- Last enriched (probe, favicon, geo)
- 2026-09-20 16:45Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 400
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
Nothing indexed for this service or its provider yet. Not a claim that it is unused — only that we hold no record. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service B20 Check 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=B20%20Check' 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://b20check.com/v1/verify/:address, 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. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402, or use an organization key from https://roundhouseai.io/dashboard/team. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.