#stocks-etfs

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.

api.oanor.com/rvol-api

The volatility-coiling setups breakout traders hunt, computed live from Yahoo Finance daily OHLC — no key, nothing stored. Markets do not trend or chop at random: tight-range days cluster and precede expansion, and the classic edge — Toby Crabel's NR7 (the narrowest daily range of the last seven), the inside day (a bar wholly inside the prior one) and the outside day (a bar that engulfs it) — is that a coiled spring releases. This API measures the coil and the release. For each instrument it returns today's range as a percentile of its recent range (low = contracted/coiling, high = already expanded), whether today is an NR7, NR4, inside or outside day, the average daily range, and the historical frequency of each setup. Crucially it also returns the follow-through: after an NR7, how often the next day broke the NR7 day's high or low and how often its range expanded — the base rate that tells you whether the coil is worth trading. The asset endpoint returns one instrument's full range profile; the screener endpoint ranks the universe by contraction (most coiled, lowest current range percentile — the breakout candidates) or by realised range. This is the range-contraction / NR7 breakout-setup cut — distinct from the candlestick-pattern API (named reversal/continuation shapes, not range size), the volatility dashboard (level, not the coil), and the gap and price APIs. It is the squeeze before the move.

api.oanor.com/rangeexpansion-api

The overnight-gap behaviour day-traders actually trade, computed live from Yahoo Finance daily OHLC — no key, nothing stored. A gap is the jump between yesterday's close and today's open — the move that happens while the market is shut, on overnight news and futures drift. Traders live and die on two questions: how often does a name gap, and does the gap fill (price retraces to yesterday's close) or run (it keeps going). This API answers both with hard frequencies. For each instrument it returns how often it gaps up and down beyond a configurable threshold, the average size of up- and down-gaps, the gap-fill rate (the share of gaps where price traded back through the prior close intraday — for an up-gap, the day's low reaching the prior close), and the continuation rate (how often the day closes in the direction of the gap rather than fading it), plus the largest recent gaps. The asset endpoint returns one instrument's full gap profile with its biggest recent gaps; the screener endpoint ranks a universe of liquid stocks and ETFs by gappiness or gap-fill rate, surfacing the names that gap most and the ones whose gaps reliably fill. This is the opening-gap / overnight-jump microstructure cut — distinct from the price, candlestick-pattern, volatility and risk APIs in the catalogue. It is what happens between the close and the open.

api.oanor.com/gapstats-api