{"uid":"cap_7jPdRL_uUyiZhpBUfh523","slug":"coincap-market-cap-history-35ca7a71","name":"CoinCap Market Cap History","description":"CoinCap gives AI agents, apps, and developers real-time cryptocurrency market data.\n\nTwo ways to access:\n- **API key** — sign up at https://coincap.io and pass `Authorization: Bearer <key>` or `?apiKey=<key>`.\n- **Keyless x402** (agents) — the 10 `agentFriendly` endpoints accept per-call USDC payment on Base via the [x402 protocol](https://x402.gitbook.io/x402). No signup needed. See `/.well-known/x402.json` for the machine-readable payment catalog.","url":"https://rest.coincap.io/v3/agentFriendly/asset_mcap_history/%7Bslug%7D","method":"GET","headers":{},"bodySchema":{"type":"object","required":["slug"],"properties":{"slug":{"type":"string"}}},"responseSchema":{"type":"object"},"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_T8uNKz2MlMedeEdd2wrph","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 historical market capitalization data for a specific cryptocurrency asset by slug","exampleAgentPrompt":"Can you pull the historical market cap data for bitcoin from CoinCap so I can see how its market capitalization has changed over time?","exampleUseCases":[{"title":"Crypto market cap trend research","prompt":"Show me the full historical market cap series for ethereum so I can see how it grew from early days to now."},{"title":"Portfolio valuation context","prompt":"Pull the market cap history for solana from CoinCap — I want to understand its market size trajectory before deciding on my position."},{"title":"Comparative market analysis","prompt":"Get me the historical market cap data for cardano using its slug 'cardano' so I can compare it against other layer-1 blockchains."}],"resultDescription":"Returns a time-series dataset of market capitalization values for the specified cryptocurrency, including historical data points with timestamps and corresponding market cap figures in USD, allowing trend analysis over time.","failureModes":["Invalid or misspelled asset slug returns a 404 or empty dataset","Unknown slug not in CoinCap database returns an error","Missing or invalid API key / failed x402 payment returns 401 or 402","Rate limiting may occur if too many requests are made in quick succession","Network timeouts for slow connections"],"whenToPreferThis":"Use this endpoint when you need historical market capitalization data for a specific cryptocurrency identified by its CoinCap slug. Prefer this over price history endpoints when the analysis specifically concerns market cap (circulating supply × price) rather than raw price. It is ideal for trend analysis, valuation context, or comparing a coin's growth trajectory over time. The x402 per-call payment model makes it accessible without API key registration for one-off agent queries.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T06:48:44.053Z","isFirstParty":false}