> ## 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 premium > Premium or discount of each spot ETF's market price to its net asset value. Premium or discount of each fund's market price to its net asset value. Available for BTC and ETH. As with [flows](/api/v2/etf/flows), check `meta.extra.days_since_latest` before treating the last point as current. ## OpenAPI ````yaml GET /etf/premium 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/premium: get: tags: - ETF summary: Spot ETF premium or discount to NAV description: >- Premium or discount of each fund's market price to its net asset value. Available for BTC and ETH. operationId: get_etf_premium_etf_premium_get parameters: - name: symbol in: query required: false schema: enum: - BTC - ETH type: string description: Underlying asset. default: BTC title: Symbol description: Underlying asset. - 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) ````