{"uid":"cap_2cQCpajV_YBozVyUPZHbH","slug":"sitecheck-api-prediction-market-build-buy-transaction-8c8e6c60","name":"SiteCheck API – Prediction Market Build Buy Transaction","description":"Build an unsigned Panta buy transaction (Solana v0, base64, plus the raw instructions) for your own wallet to sign and broadcast. SiteCheck never signs, holds keys or custodies funds. Then report the signature to POST /api/markets/report (free).","url":"https://api.sitecheck-api.workers.dev/api/markets/build-buy?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"id":{"type":"string","description":"Panta market id (the market's event address, base58), from GET /api/markets"},"side":{"type":"string","description":"yes or no"},"wallet":{"type":"string","description":"The buyer's Solana wallet (base58). It pays and signs; SiteCheck never does."},"amountUsdc":{"type":"string","description":"USDC to spend, as a decimal string, e.g. \"5.00\""},"maxSlippageBps":{"type":"integer","description":"1-5000, default 100 (1%)"}}},"responseSchema":{"type":"json","example":{"order":{"feeUsdc":"0.10","orderId":"ord_...","quoteId":"qt_...","expectedShares":"15.80"},"disclaimer":"Information only, not financial advice.","transaction":{"data":"AQAAAA...","format":"solana-v0","signed":false,"encoding":"base64","feePayer":"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM"},"instructions":[{"data":"<base64>","accounts":[],"programId":"..."}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_w5hnalwbdvISkQCGVMOnr","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Builds an unsigned Solana transaction to buy YES or NO shares in a Panta prediction market for a given USDC amount","exampleAgentPrompt":"Build me an unsigned Solana buy transaction to purchase YES shares in Panta market 'AbCdEfGhIjKlMnOpQrStUvWxYz12345678' using 5.00 USDC from my wallet 9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM, with a max slippage of 1%.","exampleUseCases":[{"title":"Betting YES on an election outcome","prompt":"I want to buy YES shares on the Panta market for the 2024 Senate race — market ID is 'SenateRace2024Base58Id' — spend 10.00 USDC from my wallet 9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM and keep slippage under 2%."},{"title":"Taking the NO side on a sports event","prompt":"Build me a transaction to buy NO shares in Panta market 'NBAFinals2024EventBase58' using 25.00 USDC from wallet 9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM — I'm okay with up to 1.5% slippage."},{"title":"Agent auto-trading on a crypto price market","prompt":"Automatically prepare an unsigned Solana buy transaction for YES shares in Panta market 'BTCabove100kBase58Id' spending 3.50 USDC from wallet 9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM, max slippage 50 basis points, so I can sign and broadcast it myself."}],"resultDescription":"Returns an unsigned base64-encoded Solana v0 transaction ready for the buyer to sign and broadcast, along with order metadata (orderId, quoteId, expectedShares, feeUsdc) and raw Solana program instructions. A disclaimer notes the data is informational only, not financial advice.","failureModes":["Invalid or unknown Panta market ID returns an error","Invalid Solana wallet address (not valid base58) causes rejection","Slippage exceeds maxSlippageBps threshold resulting in order failure","Insufficient USDC amount below minimum trade size","x402 payment failure if USDC payment on Base/Solana is not completed","Malformed amountUsdc string (e.g. non-decimal) causes parse error"],"whenToPreferThis":"Use this endpoint when an AI agent needs to programmatically prepare a buy order for a Panta prediction market on Solana without requiring a prior API key or signup. It is the right choice when you have a market ID from the /api/markets listing, know the side (yes/no) and USDC amount, and need to hand an unsigned transaction back to the user or another signing agent. Prefer this over manually constructing Solana transactions or using exchange-specific APIs when working within the Panta/SiteCheck ecosystem.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-11-01T06:35:41.846Z","isFirstParty":false,"canonicalSlug":"sitecheck-api-prediction-market-build-buy-transaction-8c8e6c60"}