{ "x402Version": 2, "id": 13034, "slug": "13034", "resource": "https://chess402.vercel.app/api/masters", "description": "Masters opening explorer for a position. Returns top moves, win/draw/loss rates, and recent top master games from the Lichess masters database.", "type": "http", "accepts": [ { "scheme": "exact", "network": "eip155:8453", "payTo": "0xfbd46201267609ad3c66bd1b99b7f1cc80b1852f", "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913", "amount": "3000", "maxTimeoutSeconds": 300 } ], "outputSchema": { "bazaar": { "info": { "input": { "body": { "fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", "moves": 12, "play": "e2e4,e7e5", "topGames": 4 }, "bodyType": "json", "method": "POST", "type": "http" }, "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 }, "type": "json" } }, "schema": { "$schema": "https://json-schema.org/draft/2020-12/schema", "properties": { "input": { "additionalProperties": false, "properties": { "body": { "$schema": "https://json-schema.org/draft/2020-12/schema", "additionalProperties": false, "description": "Masters opening explorer request: FEN plus optional filters and play sequence.", "properties": { "fen": { "description": "Standard FEN position string, e.g. 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1'", "maxLength": 100, "minLength": 15, "type": "string" }, "moves": { "description": "Max number of top moves to return. Default 12.", "maximum": 50, "minimum": 1, "type": "integer" }, "play": { "description": "Comma-separated UCI move sequence to apply to the FEN before lookup (e.g. 'e2e4,e7e5').", "maxLength": 500, "type": "string" }, "since": { "description": "Include games from this year onward.", "maximum": 2100, "minimum": 1500, "type": "integer" }, "topGames": { "description": "Number of recent top games to include. Default 4.", "maximum": 15, "minimum": 0, "type": "integer" }, "until": { "description": "Include games up to this year.", "maximum": 2100, "minimum": 1500, "type": "integer" } }, "required": [ "fen" ], "type": "object" }, "bodyType": { "enum": [ "json", "form-data", "text" ], "type": "string" }, "method": { "enum": [ "POST", "PUT", "PATCH" ], "type": "string" }, "type": { "const": "http", "type": "string" } }, "required": [ "type", "method", "bodyType", "body" ], "type": "object" }, "output": { "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" } }, "required": [ "input" ], "type": "object" } } }, "tags": [ "bazaar" ], "sourceHost": "chess402.vercel.app", "lastUpdated": "2026-09-17T03:59:42.112Z", "quality": { "calls30d": 1, "uniquePayers30d": 1, "lastCalledAt": "2026-09-17T03:59:41.948Z" }, "liveness": {}, "verified": false, "featured": false, "provider": { "host": "chess402.vercel.app", "manifest_name": "chess402.vercel.app", "source": "cdp-mirror", "source_manifest_url": "https://api.cdp.coinbase.com/platform/v2/x402/discovery/resources", "submitted_at": "2026-09-18T22:00:31.484Z" } }