{"uid":"cap_tGJTQ26TiX-E781r1x_dz","slug":"wintergreen-x402-endpoint-migration-guide-api-key-to-x402-62abd5ae","name":"Wintergreen x402 Endpoint Migration Guide (API Key to x402)","description":"Payment-gated crypto trading intelligence for AI agents.\n    \n## Categories\n- **Hyperliquid Signals**: Real-time funding divergence, lead-lag correlation, liquidation clusters, session volume area levels\n- **Quant Methodology**: Backtesting walk-forward validation, strategy generation with kill battery (19 rules), risk management with Kelly sizing, regime detection, execution frameworks, agent orchestration\n- **Market Insights**: 22 crypto microstructure observations — funding, liquidation, orderbook, regime, flow, anomaly\n- **Power Markets**: ERCOT field guide, merit-order model, duck curve analysis\n- **Career Guides**: Firefighter oral board prep, medical coding, ATSA, contractor estimating\n- **Trust Scoring**: x402 endpoint verification, P2D badges\n\n## Payment\nAll paid endpoints return HTTP 402 with USDC on Base (eip155:8453). \nSign EIP-712 TransferWithAuthorization and retry with X-PAYMENT header.\nPayTo: 0xAe9834d71F1Bd989A0dc17593451af823E31CeeD","url":"https://x402.wintergreen.uk/api/v1/knowledge/endpoint-migration-apikey-to-x402","method":"GET","headers":{},"bodySchema":{"type":"object","properties":{"_file_slug":{"type":"string"},"_route_slug":{"type":"string"}}},"responseSchema":{},"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":"down","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_qZjl5bIk9dyLbIfPF8e5L","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":"Returns a payment-gated knowledge article explaining how to migrate from API-key authentication to the x402 micropayment protocol for AI agents.","exampleAgentPrompt":"Can you pull up the Wintergreen guide on migrating from API key authentication to x402 micropayments — I want to understand the step-by-step process for switching my API over to the EIP-712 payment flow?","exampleUseCases":[{"title":"Adopting x402 for a new API","prompt":"I'm building an API and want to drop API keys entirely in favor of x402 crypto micropayments — can you fetch the Wintergreen migration guide that walks through how to make that switch?"},{"title":"Explaining x402 auth to a dev team","prompt":"My team is used to API key auth and I need a clear explanation of how x402 works as a replacement — grab that Wintergreen endpoint migration guide so I can share it with them."},{"title":"Debugging x402 payment integration","prompt":"I'm getting 402 errors when trying to authenticate with x402 instead of my old API key — can you retrieve the Wintergreen migration guide to help me figure out what I'm missing in the EIP-712 flow?"}],"resultDescription":"A knowledge article (text/markdown or structured content) detailing the process of migrating an API from traditional API-key authentication to the x402 micropayment protocol, including EIP-712 TransferWithAuthorization signing, header conventions, and agent integration patterns. Returned after successful USDC payment of $1.50 on Base (eip155:8453).","failureModes":["HTTP 402 returned if payment header is missing or invalid — agent must sign EIP-712 and retry with X-PAYMENT header","Invalid file or route slug returns empty or error response due to unspecified response schema","Payment rejected if USDC balance insufficient on Base chain","Network or RPC errors on Base chain causing payment verification failure","Content unavailable if slug parameters do not match a known knowledge article"],"whenToPreferThis":"Choose this endpoint when an AI agent or developer needs authoritative guidance on transitioning from API-key-based authentication to the x402 micropayment standard. It is specifically useful when building agent-native APIs that monetize via per-call crypto micropayments rather than subscription keys, and when the developer wants protocol-level detail on EIP-712 signing and x402 header conventions.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T16:29:07.439Z","isFirstParty":false}