We're building the most comprehensive crypto data API we can, and it's still growing — there's always a coin, a field or an endpoint we haven't got to yet.
Please tell us about any data you think Crypto Data API should nail but doesn't. We're data nerds who love to geek out about market data, trading bots, AI agents, or how to make your trading stack work in general. Prefer a form? Send feedback.
— Sam and the CDA team
Join us on DiscordSpot bitcoin ETFs saw net inflows of $2.65B over 21 trading days in September 2026. The largest single-day inflow was +$999.0M on Monday, September 21, 2026, and the largest outflow was −$450.4M on Tuesday, September 15, 2026. 13 of the 21 days closed with net inflows and 8 with net outflows. By fund, IBIT led with net inflows of $1.81B, followed by FBTC ($682.2M); GBTC had the largest net outflows at $259.3M. August 2026 saw net inflows of $3.54B over 21 trading days, a month-over-month change of −$891.4M.
One row per settled US trade date, in USD millions. Each fund column is that fund's net creation (positive) or redemption (negative); the last column is the net total across every US spot bitcoin ETF. Link to a day with #YYYY-MM-DD, e.g. #2026-09-30.
Settled figures only: a day appears once every fund has reported. Sources: Farside Investors (primary, with the per-fund breakdown) and SoSoValue (backup, net total only).
Each fund's net flow summed over the 21 trading days with a per-fund breakdown, largest inflow first.
GET /api/v1/market-intelligence/etf/btc/flows returns the newest days settled trade dates (up to 1000), oldest first: each row has trade_date, flow_usd (the net total across every fund) and its source. days=43 reaches back to 2026-09-01; keep the rows whose trade_date starts with 2026-09.
curl -H "X-API-Key: cdk_live_yourkey" \ "https://cryptodataapi.com/api/v1/market-intelligence/etf/btc/flows?days=43"
The day still being reported comes back separately as in_progress and is never in flows. Swap btc for eth or sol.
Pro unlocks every coin on the quant surfaces — whale positioning, dealer gamma (GEX), short-horizon regime probabilities, L2 order-book depth and full-universe funding — on the same key you already hold.
AI agents: subscribe key-in-hand with no browser and no card —
POST /api/v1/payments/agent-subscribe
(x402 gasless USDC on Base, Ethereum or Solana; call it once for the 402 payment instructions, sign, call again).