> ## Documentation Index > Fetch the complete documentation index at: https://docs.backquant.com/llms.txt > Use this file to discover all available pages before exploring further. # ETF flows > Daily creations and redemptions for spot crypto ETFs, per fund and in total, with running cumulatives. Daily creations and redemptions for spot crypto ETFs: per fund, in total, and as running cumulatives. `region=us` (default) covers the US spot ETFs. `region=hk` covers the Hong Kong listings and exists for BTC only. ## Read the freshness field ETF flows publish on trading days, so the newest date is normally the previous business day, and three days old across a weekend is entirely normal. Every response reports `meta.extra.latest_date` and `meta.extra.days_since_latest`. **Alert on `days_since_latest`**, not on the absence of an error: this data is cached with a generous expiry so that a collection outage degrades to serving the last known values rather than failing, which means a stale response looks exactly like a fresh one unless you check. ```json theme={null} { "meta": { "extra": { "region": "us", "latest_date": "2026-08-21", "days_since_latest": 1 } } } ``` If no data is available at all the endpoint returns `404` rather than an empty series, because an empty series reads as "there were no flows", which is a different claim. ## See also ## OpenAPI ````yaml GET /etf/flows openapi: 3.1.0 info: title: BackQuant API v2 description: >- # BackQuant API v2 Options + gamma-exposure focused public API. Built on the same data the BackQuant Pro Terminal renders - pre-computed every 30s, served from cache. ## What's in v2 * **Discovery**: `/v2/symbols` (universe + per-symbol freshness + supported endpoint list), `/v2/expiries` (active expiry tokens with DTE), `/v2/status` (per-symbol-per-category health with thresholds + overall classification). * **GEX**: composable levels (HVL / call wall / put support / max-pain / expected move / gamma-flip zones), strike profile with typed expiry filter, expiry profile, strike × expiry heatmap with downsampling, greek time-heatmap with DTE/OI/IV filters, history (cursor-paginated), Postgres-backed stress history, **per-expiry max-pain with pain curve**. * **Options**: filtered options chain with two-layer projection (top-level `?fields=` and per-contract `?include=oi,iv,greeks,bid_ask,volume,gex`) plus moneyness filter (`?moneyness_min=0.9&moneyness_max=1.1`), expiry summary table, full IV suite (surface / term structure / 25Δ-10Δ skew / curves / **single-expiry smile** / IV-RV history / VRP), expected move, **Breeden-Litzenberger probability density and surface**, typed greek profiles (delta / theta / vanna / charm / vega), strike × time charm/vega surfaces, strike × expiry 3D greek surface, OI by expiry + history, put/call ratio (intraday or daily), 0DTE & weekly premium tide, dated-futures term structure. * **Liquidation**: heatmap + leverage-tiered distribution. * **Multi**: `/v2/multi/gex/levels` - bundled multi-symbol read across the universe in one round-trip, with the same `?include=` model as the single-symbol endpoint. ## Authentication Every v2 route (except `/v2/openapi.json`, `/v2/docs`, `/v2/redoc`, and `/v2/health`) requires the `X-API-Key` header. ``` X-API-Key: bq_live_your_api_key_here ``` **Get your API key at [backquant.com/api-access](https://backquant.com/api-access).** The same key works across v1 and v2 - if you already have a v1 key, no re-issuance is needed. ## Rate limits Two budgets, both derived from your subscription tier: a **monthly request allowance** per account, and a **per-minute burst** per key. Size your integration against the monthly figure - sustained polling at the burst rate exhausts the month early. | Plan | Monthly allowance | Burst | Sustained | |---------------------------|-------------------|----------|-------------| | Starter (Terminal Yearly) | 10,000 req/month | 10/min | ~333/day | | Standard (Crypto API) | 250,000 req/month | 60/min | ~8,300/day | | Pro (Terminal + API) | 1,000,000/month | 120/min | ~33,000/day | | Enterprise | custom | 600/min | custom | Headers `X-RateLimit-Limit / -Remaining / -Reset` (burst) and `X-Quota-Limit / -Used / -Remaining / -Period` (monthly) are included in every response; the rate-limit triple is echoed inside `meta.rate_limit` when populated by middleware. Exceeding either budget returns `429`. The live ladder is served at `GET /v2/meta` under `rate_limits`. ## Response envelope ```json { "success": true, "data": { ... }, "meta": { "version": "2.0", "timestamp": "2026-04-29T12:00:00.000Z", "request_id": "req_…", "symbol": "BTCUSDT", "spot_price": 67213.5, "computed_at": "2026-04-29T11:59:48.000Z", "freshness_seconds": 12.0, "source": ["deribit","bybit","okx","binance","derive","thalex","delta_india","delta"], "exchanges_filtered": ["deribit","bybit"] } } ``` ## Errors ```json { "success": false, "error": { "code": "NOT_FOUND", "message": "No data for BTCUSDT" }, "meta": { "version": "2.0", "timestamp": "..." } } ``` | Code | When | |-----------------------|------| | `UNAUTHORIZED` | Missing or invalid API key | | `FORBIDDEN` | Subscription doesn't allow API access | | `NOT_FOUND` | Symbol/expiry/etc. not present in cache | | `VALIDATION_ERROR` | Bad query parameters | | `RATE_LIMIT_EXCEEDED` | Per-tier limit hit | | `UPSTREAM_ERROR` | Cache or DB temporarily unreachable | | `INTERNAL_ERROR` | Anything else | version: '2.7' servers: [] security: [] tags: - name: Meta description: Unauthenticated metadata + endpoint catalog (planning your integration) - name: Discovery description: Symbol catalog, active expiries, and service status - name: GEX description: Gamma exposure analytics - name: Options description: Options chain, IV, greeks, probability, premium tide - name: Liquidation description: Liquidation heatmap and distribution - name: Multi description: Bundled multi-symbol endpoints (single round-trip across the universe) paths: /etf/flows: get: tags: - ETF summary: Spot ETF daily flows description: >- Daily creations and redemptions for spot crypto ETFs, per fund and in total, with running cumulatives. `region=us` (default) covers the US spot ETFs. `region=hk` covers the Hong Kong listings and is available for BTC only. Flows publish on trading days, so the newest date is normally the previous business day. Check `meta.extra.days_since_latest` before treating the last point as current. operationId: get_etf_flows_etf_flows_get parameters: - name: symbol in: query required: false schema: enum: - BTC - ETH - SOL - XRP type: string description: Underlying asset. default: BTC title: Symbol description: Underlying asset. - name: region in: query required: false schema: enum: - us - hk type: string description: Listing region. default: us title: Region description: Listing region. - name: X-API-Key in: header required: false schema: anyOf: - type: string - type: 'null' title: X-Api-Key responses: '200': description: Successful Response content: application/json: schema: {} '401': description: Invalid or missing API key content: application/json: example: success: false error: code: UNAUTHORIZED message: Invalid API key meta: version: '2.0' timestamp: '2026-04-29T12:00:00Z' '404': description: No data available for the requested resource content: application/json: example: success: false error: code: NOT_FOUND message: No data for BTCUSDT meta: version: '2.0' timestamp: '2026-04-29T12:00:00Z' '422': description: Validation error on query parameters content: application/json: example: success: false error: code: VALIDATION_ERROR message: Invalid request parameters details: errors: [] meta: version: '2.0' timestamp: '2026-04-29T12:00:00Z' '429': description: Rate limit exceeded content: application/json: example: success: false error: code: RATE_LIMIT_EXCEEDED message: Rate limit exceeded. Try again later. meta: version: '2.0' timestamp: '2026-04-29T12:00:00Z' security: - ApiKeyAuth: [] components: securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-Key description: Your BackQuant API key (same key as v1) ````