# Relative Volume (RVOL) API > Which markets are trading on abnormal volume right now — the first scan a day-trader runs to find what is "in play" — computed live from Yahoo Finance daily volume, no key, nothing stored. Price tells you where a market is; volume tells you whether anyone cares. A stock drifting on half its normal volume is noise; the same stock on three times its average is a market reacting to something — earnings, news, a breakout — and that is where the opportunity and the risk live. Relative volume (RVOL) is today's volume divided by its recent average: 1.0 is a normal day, 2.0 is double, and anything above signals unusual participation. For each instrument this API returns today's volume, its 20- and 50-day average volume, the RVOL against each, where today's volume sits as a percentile of the window, the dollar (notional) volume for liquidity, and whether volume is trending up or down. The asset endpoint returns one instrument's full volume profile; the screener endpoint ranks the universe by RVOL, putting the names trading on the most unusual volume — the ones in play — at the top. This is the relative-volume / unusual-activity cut — distinct from the bring-your-own-series volume-indicator tools (OBV, MFI), the crypto volume-by-price profile, the order-flow tape and the price APIs. It is the volume that is out of the ordinary. ## Authentication All requests require your oanor API key in the `x-oanor-key` header. Get one at https://www.oanor.com/developer/keys. ```bash curl -H "x-oanor-key: oanor_live_…" "https://api.oanor.com/rvol-api/..." ``` ## Pricing - **Free** (Free) — 695 calls/Mo, 2 req/s - **Starter** ($12/Mo) — 15,800 calls/Mo, 6 req/s - **Pro** ($35/Mo) — 84,500 calls/Mo, 16 req/s - **Mega** ($78/Mo) — 482,000 calls/Mo, 40 req/s ## Endpoints ### Screener #### `GET /v1/screener` — Rank the universe by RVOL, volume percentile or dollar volume **Parameters:** - `metric` (query, optional, string) — rvol, volume_percentile or dollar_volume Example: `rvol` - `window` (query, optional, string) — Lookback in trading days (60-500) Example: `90` - `class` (query, optional, string) — index, sector, commodity, bond, stock, crypto or all Example: `all` **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/rvol-api/v1/screener?metric=rvol&window=90&class=all" ``` **Response:** ```json { "data": { "note": "Ranked by rvol over window_days of daily volume. RVOL is today's volume divided by the prior 20- (or 50-) day average: 1.0 normal, 2.0 double, 3.0+ extreme. volume_percentile places today's volume in the window. dollar_volume is volume x close. Read fresh per call, nothing cached.", "class": "all", "count": 22, "metric": "rvol", "source": "Yahoo Finance", "results": [ { "name": "Gold ETF", "rank": 1, "read": "elevated volume", "class": "commodity", "symbol": "GLD", "rvol_20": 1.87, "rvol_50": 1.77, "available": true, "volume_trend": "falling", "dollar_volume": 4852372452, "volume_percentile": 73.3 }, { "name": "Crude Oil ETF", "rank": 2, "read": "elevated volume", "class": "commodity", "symbol": "USO", "rvol_20": 1.7, "rvol_50": 0.74, "available": true, "volume_trend": "falling", "dollar_volume": 1557528956, "volume_percentile": 48.9 }, { "name": "S&P 500 ETF", "rank": 3, "read": "elevated volume", "class": "index", "symb …(truncated, see openapi.json for full schema) ``` ### Asset #### `GET /v1/asset` — Full volume profile of one instrument **Parameters:** - `symbol` (query, required, string) — Universe symbol Example: `NVDA` - `window` (query, optional, string) — Lookback in trading days (60-500) Example: `90` **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/rvol-api/v1/asset?symbol=NVDA&window=90" ``` **Response:** ```json { "data": { "name": "Nvidia", "note": "RVOL = today's volume / prior 20-day average volume (rvol_50 uses the 50-day). volume_percentile is where today's volume ranks in the window. dollar_volume = today's volume x close (notional liquidity). Read fresh per call, nothing cached.", "class": "stock", "reads": { "rvol": "normal volume", "trend": "20-day volume above 50-day — participation building" }, "source": "Yahoo Finance", "symbol": "NVDA", "rvol_20": 0.88, "rvol_50": 0.97, "window_days": 90, "observations": 90, "today_volume": 157872000, "volume_trend": "rising", "avg_volume_20": 179067235, "avg_volume_50": 162349018, "dollar_volume": 32343235869, "volume_percentile": 32.2, "avg_dollar_volume_20": 38870693608 }, "meta": { "timestamp": "2026-06-12T10:34:40.445Z", "request_id": "e9ac8f65-2c49-4591-a876-7ea65cdc5d58" }, "status": "ok", "message": "Asset volume profile retrieved successfully", "success": true } ``` ### Universe #### `GET /v1/universe` — The volume-bearing universe and its classes **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/rvol-api/v1/universe" ``` **Response:** ```json { "data": { "note": "The volume-bearing universe the screener ranks — ETFs, large-cap stocks and crypto (FX has no exchange volume). Pass class= to a screener call to rank within one class.", "count": 22, "assets": [ { "name": "S&P 500 ETF", "class": "index", "symbol": "SPY" }, { "name": "Nasdaq 100 ETF", "class": "index", "symbol": "QQQ" }, { "name": "Russell 2000 ETF", "class": "index", "symbol": "IWM" }, { "name": "Dow Jones ETF", "class": "index", "symbol": "DIA" }, { "name": "Technology Sector", "class": "sector", "symbol": "XLK" }, { "name": "Financials Sector", "class": "sector", "symbol": "XLF" }, { "name": "Energy Sector", "class": "sector", "symbol": "XLE" }, { "name": "Gold ETF", "class": "commodity", "symbol": "GLD" }, { "name": "Silver ETF", "class": "commodity", "symbol": "SLV" }, { …(truncated, see openapi.json for full schema) ``` ### Meta #### `GET /v1/meta` — Service metadata **Example:** ```bash curl -H "x-oanor-key: $KEY" \ "https://api.oanor.com/rvol-api/v1/meta" ``` **Response:** ```json { "data": { "note": "metric is rvol (default), volume_percentile or dollar_volume. window is 60-500 trading days (default 90). class filters to index/sector/commodity/bond/stock/crypto (default all). RVOL = today's volume / prior 20-day average. FX is excluded (no exchange volume). Read fresh per call, nothing cached.", "source": "Yahoo Finance daily volume, live", "classes": [ "index", "sector", "commodity", "bond", "stock", "crypto" ], "metrics": [ "rvol", "volume_percentile", "dollar_volume" ], "service": "rvol-api", "endpoints": { "GET /v1/meta": "This document.", "GET /v1/asset": "Full volume profile of one instrument (symbol=NVDA, window=90).", "GET /v1/screener": "Rank the universe by RVOL, volume percentile or dollar volume (metric=rvol, window=90, class=all).", "GET /v1/universe": "The volume-bearing universe and its classes." }, "description": "Relative volume (RVOL) & unusual activity — which markets are trading on abnormal volume right now, live from Yahoo Finance daily volume (no key, nothing stored). RVOL is today's volume over its recent average: 1.0 normal, 2.0 double, 3.0+ extreme. For each instrument it returns today's volume, the 20/50-day average, the RVOL against each, the volume percentile, the dollar volume and whet …(truncated, see openapi.json for full schema) ``` --- Marketplace page: https://www.oanor.com/api/rvol-api OpenAPI spec: https://www.oanor.com/api/rvol-api/openapi.json