CH
Developer Tool · x402 · early usage
Masters opening explorer for a position
Masters opening explorer for a position. Returns top moves, win/draw/loss rates, and recent top master games from the Lichess masters database.
by chess402.vercel.app · discovered, not yet claimed by its owner · updated 2026-10-06
30d calls2
30d payers2
MethodPOST
Outputjson
Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.
What it does
Masters opening explorer for a position. Returns top moves, win/draw/loss rates, and recent top master games from the Lichess masters database.
Tags: bazaar
Call contract
- Method
- POST
- Input
- json
- Output
- json
- Last paid call
- 2026-10-06
Input example from Bazaar metadata
{
"fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
"moves": 12,
"play": "e2e4,e7e5",
"topGames": 4
}Output example
{
"black": 198217,
"draws": 311203,
"moves": [
{
"averageRating": 2434,
"black": 64210,
"draws": 98421,
"game": null,
"opening": {
"eco": "C42",
"name": "Russian Game"
},
"san": "Nf3",
"uci": "g1f3",
"white": 152340
}
],
"opening": {
"eco": "C20",
"name": "King's Pawn Game"
},
"topGames": [
{
"black": {
"name": "Carlsen, M.",
"rating": 2882
},
"id": "Sxov6E94",
"month": "2019-08",
"uci": "g1f3",
"white": {
"name": "Caruana, F.",
"rating": 2818
},
"winner": "white",
"year": 2019
}
],
"white": 482141
}Use with an agent
- Discover. Agents find this listing with
GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP toolsearch_resources, or/discovery/resources. - Inspect. Fetch
/resources/55092.jsonfor the price and payment options. - Pay. Call
GET https://chess402.vercel.app/api/masters. The provider answers402with its payment requirements. An x402 client signs one of the options below and retries withPAYMENT-SIGNATURE. - Execute. The provider returns
200with the data. Agent Bazaar is not in the request path and never sees your payment.
For humans
You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.
Pricing & payment
- Price
- $0.003 / request
- Protocol
- x402 v2
- Auth
- No account or API key. Pay per request.
- Networks
- Base
- Demand
- 2 calls · 2 unique payers in 30d (public x402 Bazaar data)
x402 payment requirements
| Scheme | Network | Asset | Amount | Pay to | Timeout |
|---|---|---|---|---|---|
| exact | Base eip155:8453 | USDC | $0.003 | 0xfbd46201267609ad3c66bd1b99b7f1cc80b1852f | 300s |
accepts[] (raw JSON)
[
{
"scheme": "exact",
"network": "eip155:8453",
"payTo": "0xfbd46201267609ad3c66bd1b99b7f1cc80b1852f",
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"amount": "3000",
"amountUsd": 0.003,
"maxTimeoutSeconds": 300
}
]Schemas
Output schema (JSON Schema)
{
"properties": {
"example": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"additionalProperties": {},
"description": "Masters database aggregate stats for the position.",
"properties": {
"black": {
"description": "Total black wins at this position.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
},
"draws": {
"description": "Total draws at this position.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
},
"moves": {
"description": "Top moves ordered by frequency.",
"items": {
"additionalProperties": {},
"properties": {
"averageRating": {
"description": "Average rating of players who played this move.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
},
"black": {
"description": "Games won by black from this move.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
},
"draws": {
"description": "Drawn games from this move.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
},
"game": {
"anyOf": [
{
"additionalProperties": {},
"properties": {
"black": {
"additionalProperties": false,
"description": "Black player.",
"properties": {
"name": {
"description": "Player name.",
"type": "string"
},
"rating": {
"description": "Player rating.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"name",
"rating"
],
"type": "object"
},
"id": {
"description": "Lichess game id.",
"type": "string"
},
"month": {
"description": "Month string (YYYY-MM).",
"type": "string"
},
"uci": {
"description": "UCI move played in this game.",
"type": "string"
},
"white": {
"additionalProperties": false,
"description": "White player.",
"properties": {
"name": {
"description": "Player name.",
"type": "string"
},
"rating": {
"description": "Player rating.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"name",
"rating"
],
"type": "object"
},
"winner": {
"anyOf": [
{
"enum": [
"white",
"black"
],
"type": "string"
},
{
"type": "null"
}
],
"description": "Winner, or null for a draw."
},
"year": {
"description": "Year the game was played.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"uci",
"id",
"winner",
"white",
"black",
"year"
],
"type": "object"
},
{
"type": "null"
}
],
"description": "Representative game for this move, if available."
},
"opening": {
"anyOf": [
{
"additionalProperties": {},
"properties": {
"eco": {
"description": "ECO opening code.",
"type": "string"
},
"name": {
"description": "Opening name.",
"type": "string"
}
},
"required": [
"eco",
"name"
],
"type": "object"
},
{
"type": "null"
}
],
"description": "ECO opening classification for this move, when recognized."
},
"san": {
"description": "SAN move string.",
"type": "string"
},
"uci": {
"description": "UCI move string.",
"type": "string"
},
"white": {
"description": "Games won by white from this move.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"uci",
"san",
"white",
"draws",
"black"
],
"type": "object"
},
"type": "array"
},
"opening": {
"anyOf": [
{
"additionalProperties": {},
"properties": {
"eco": {
"description": "ECO opening code.",
"type": "string"
},
"name": {
"description": "Opening name.",
"type": "string"
}
},
"required": [
"eco",
"name"
],
"type": "object"
},
{
"type": "null"
}
],
"description": "ECO opening classification for the position, when recognized."
},
"topGames": {
"description": "Recent top master games at this position.",
"items": {
"additionalProperties": {},
"properties": {
"black": {
"additionalProperties": false,
"description": "Black player.",
"properties": {
"name": {
"description": "Player name.",
"type": "string"
},
"rating": {
"description": "Player rating.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"name",
"rating"
],
"type": "object"
},
"id": {
"description": "Lichess game id.",
"type": "string"
},
"month": {
"description": "Month string (YYYY-MM).",
"type": "string"
},
"uci": {
"description": "UCI move played in this game.",
"type": "string"
},
"white": {
"additionalProperties": false,
"description": "White player.",
"properties": {
"name": {
"description": "Player name.",
"type": "string"
},
"rating": {
"description": "Player rating.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"name",
"rating"
],
"type": "object"
},
"winner": {
"anyOf": [
{
"enum": [
"white",
"black"
],
"type": "string"
},
{
"type": "null"
}
],
"description": "Winner, or null for a draw."
},
"year": {
"description": "Year the game was played.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"uci",
"id",
"winner",
"white",
"black",
"year"
],
"type": "object"
},
"type": "array"
},
"white": {
"description": "Total white wins at this position.",
"maximum": 9007199254740991,
"minimum": -9007199254740991,
"type": "integer"
}
},
"required": [
"white",
"draws",
"black",
"moves"
],
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}Example shape — generated from the schema, not a captured live response
{
"example": {
"black": 0,
"draws": 0,
"moves": [
{
"averageRating": 0,
"black": 0,
"draws": 0,
"game": null,
"opening": null,
"san": "string",
"uci": "string",
"white": 0
}
],
"opening": null,
"topGames": [
{
"black": {
"name": "string",
"rating": 0
},
"id": "string",
"month": "string",
"uci": "string",
"white": {
"name": "string",
"rating": 0
},
"winner": null,
"year": 0
}
],
"white": 0
},
"type": "string"
}Examples
curl
curl "https://chess402.vercel.app/api/masters"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paidJavaScript
const res = await fetch("https://chess402.vercel.app/api/masters");
if (res.status === 402) {
const { accepts } = await res.json();
// pay one of accepts[] via an x402 client, then retry with the payment header
}Python
import httpx
res = httpx.get("https://chess402.vercel.app/api/masters")
if res.status_code == 402:
accepts = res.json()["accepts"]
# pay one of accepts[] via an x402 client, then retry with the payment headerDetails
- Provider
- chess402.vercel.app
- Endpoint
- https://chess402.vercel.app/api/masters
- Machine-readable
/resources/55092.json