B20 Access Type
A pay-per-call API marketplace powered by x402 and Base Builder Codes. Every payment is attributed onchain via ERC-8021.
The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
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.
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",
"sample": {
"data": {
"isB20": true,
"symbol": "NADT",
"address": "0xb20000000000000000000186a08e781c38059eec",
"variant": "stablecoin",
"verdict": "open",
"checkedAt": "2026-09-11T08:08:00.447Z",
"scopesCount": 0
},
"note": "Preview of a real response — a paid call returns the full report (all signals, details & recommendation)."
},
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x973a31858f4d2125f48c880542da11a2796f12d6",
"amount": "30000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
}
],
"resource": {
"url": "https://402.com.tr/api/x402/b20-access-type",
"tags": [
"b20",
"base-token-standard",
"freeze",
"seize",
"token-safety",
"stablecoin",
"compliance",
"access",
"type",
"base",
"x402"
],
"mimeType": "application/json",
"description": "🆕 A B20 transfer policy is either a BLOCKLIST (allowed unless listed) or an ALLOWLIST (allowed ONLY if listed — a permissioned/whitelist token you can't even receive uninvited). b20-safety flags that a policy exists; this decodes its TYPE per scope (send/receive/execute/mint) — the difference between 'the issuer can block bad actors' and 'this is a permissioned RWA you can't hold uninvited'.",
"serviceName": "B20 Access Type"
},
"extensions": {
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"pathParams": {},
"queryParams": {
"address": "0xb20000000000000000000186a08e781c38059eec"
}
},
"output": {
"type": "json",
"example": {
"isB20": true,
"symbol": "NADT",
"address": "0xb20000000000000000000186a08e781c38059eec",
"variant": "stablecoin",
"verdict": "open",
"checkedAt": "2026-09-11T08:08:00.447Z",
"scopesCount": 0
}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method"
],
"properties": {
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"GET"
],
"type": "string"
},
"pathParams": {
"type": "object"
},
"queryParams": {
"type": "object",
"required": [
"address"
],
"properties": {
"address": {
"type": "string",
"description": "B20 token address"
}
}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
},
"routeTemplate": ":var1"
},
"builder-code": {
"info": {
"a": "bc_pa0gqlv1"
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"a": {
"type": "string",
"pattern": "^[a-z0-9_]{1,32}$",
"description": "App builder code"
},
"s": {
"type": "array",
"items": {
"type": "string",
"pattern": "^[a-z0-9_]{1,32}$"
},
"description": "Service builder codes"
},
"w": {
"type": "string",
"pattern": "^[a-z0-9_]{1,32}$",
"description": "Wallet builder code"
}
},
"additionalProperties": false
}
}
},
"x402Version": 2,
"alternatives": [
{
"url": "https://402.com.tr/api/x402/buy-credits?tier=0.25",
"then": "Send the returned token as the `x-credit-token` header on this and any paid call; each debits its price from the balance — no per-call signature.",
"gives": "≈8 calls at this service's price from one settlement; lowest-friction start.",
"action": "buy-credits",
"method": "POST",
"priceUsdc": "0.25",
"recommended": true
},
{
"url": "https://402.com.tr/api/x402/b20-access-type",
"gives": "Pay this exact call now over x402 — see the `accepts` array for scheme/amount/asset/payTo.",
"action": "pay-x402",
"method": "GET"
}
],
"prepaidCredits": "One x402 settlement on /api/x402/buy-credits?tier=0.25|1|5|20 mints a bearer credit token; send it as the x-credit-token header and later calls debit the balance — no wallet or signature per call after that first purchase."
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
Pay 0.03 USDC on Base to 0x973a…f12d6. The signed payment is good for 5 minutes.
- Paid to
- 0x973a…f12d6
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 30000 smallest units
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0x973a…f12d6
- Token contract
- 0x3c49…c3359
- Payment window
- 5 minutes
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x973a31858f4d2125f48c880542da11a2796f12d6",
"amount": "30000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
},
{
"asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x973a31858f4d2125f48c880542da11a2796f12d6",
"amount": "30000",
"scheme": "exact",
"network": "eip155:137",
"maxTimeoutSeconds": 300
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"pathParams": {},
"queryParams": {
"address": "0xb20000000000000000000186a08e781c38059eec"
}
},
"output": {
"type": "json",
"example": {
"isB20": true,
"symbol": "NADT",
"address": "0xb20000000000000000000186a08e781c38059eec",
"variant": "stablecoin",
"verdict": "open",
"checkedAt": "2026-09-11T03:00:46.855Z",
"scopesCount": 0
}
}
},
"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"
},
"queryParams": {
"type": "object",
"required": [
"address"
],
"properties": {
"address": {
"type": "string",
"description": "B20 token address"
}
}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
},
"builder-code": {
"info": {
"a": "bc_pa0gqlv1"
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"a": {
"type": "string",
"pattern": "^[a-z0-9_]{1,32}$",
"description": "App builder code"
},
"s": {
"type": "array",
"items": {
"type": "string",
"pattern": "^[a-z0-9_]{1,32}$"
},
"description": "Service builder codes"
},
"w": {
"type": "string",
"pattern": "^[a-z0-9_]{1,32}$",
"description": "Wallet builder code"
}
},
"additionalProperties": false
}
}
}Provenance
- Seen in the source catalog
- 2026-09-11 08:08Z
- Last indexed by Roundhouse
- 2026-09-24 08:10Z
- Last enriched (probe, favicon, geo)
- 2026-09-22 09:45Z
- 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. 30 snapshots so far. 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 Access Type 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%20Access%20Type' 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://402.com.tr/api/x402/b20-access-type, 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.