Alphanume vs FlashAlpha: IV/RV Screening, GEX, and Why Their Numbers Disagree

Alphanume and FlashAlpha both sell the gap between implied and realized volatility through an API. Pull AAPL from each on the same day and the 30-day spread differs by about half a point, and a shorter window can flip its sign. Neither feed is wrong. They are built for different jobs.

TL;DR

• Alphanume ranks IV against HV across liquid US equities once a day. Pro is $349 a month or $1,999 a year for one user, with REST, hosted MCP and 28 other datasets.
• FlashAlpha reads IV, several RV windows and gamma exposure for one symbol during the session. Growth is $299 a month with 2,500 requests a day.
• Pick Alphanume for a whole-market daily screen with settled rows. Pick FlashAlpha when the volatility reading needs dealer positioning beside it.

Disclosure: published by FlashAlpha. Alphanume's product, documentation and pricing pages were checked on November 11, 2026.

Which one to choose

Choose Alphanume if:

• You want every liquid US equity ranked by IV/HV on the same day, in one request.
• You need settled daily rows for a backtest, with a flag that separates provisional from final values.
• You also want its other datasets: short locates, dilution, buybacks and earnings move history. Pro includes all 29.
• You prefer the lower annual commitment: $1,999 a year.

Choose FlashAlpha if:

• Your next step after an IV/RV reading is a gamma exposure check: net GEX, gamma flip, call and put walls.
• You want several realized-volatility windows for one symbol, with skew and term structure in the same response.
• You trade indexes, ETFs or CME futures options as well as single stocks.
• You prefer the lower monthly bill, or want to start on a free key for limited GEX.

What Alphanume offers

Alphanume LLC sells research datasets through one subscription. Its site describes them as "proprietary datasets for overlooked market behavior". The 29 datasets cover short locates, dilution and financing events, buybacks, earnings move history, an S&P 500 risk regime, an SPX 0DTE strike band and three volatility series: IV/HV Premium, IV/HV Rank and vol of vol.

The IV/HV Premium dataset. GET /v1/iv-hv-premium returns one row per ticker per trading day: the IV of the at-the-money call in the listed expiry closest to 30 calendar days, realized volatility over the last 30 trading days of closes, the spread, the ratio, and cross-sectional ranks and z-scores.

Timing. Today's row is provisional and refreshes about every 30 minutes from 09:30 to 16:00 ET. It settles around 16:30 ET. only_final=true returns settled rows only. The universe is liquid US equities on a point-in-time basis; Alphanume does not publish a ticker count or history start date.

Access. https://api.alphanume.com/v1, key in an X-API-Key header or api_key parameter. The hosted MCP server at mcp.alphanume.com accepts OAuth or the same key. GET /v1/iv-rank places each name's IV and HV in its own trailing 252-observation range.

We found no gamma exposure, dealer positioning, option chain or Greeks dataset in Alphanume's public catalog.

How FlashAlpha covers the same job

IV/RV on Growth. GET /v1/volatility/{symbol} returns atm_iv, a realized_vol ladder (rv_5d to rv_60d) and iv_rv_spreads (vrp_5d to vrp_30d) with an assessment such as thin_premium or negative_spread. The same response carries per-expiry skew, term structure state, GEX by days to expiry, dealer hedging scenarios, and a historical_context block with percentiles and z-scores against the symbol's own history.

Dealer positioning. GET /v1/exposure/gex/{symbol} returns net_gex, gamma_flip and a per-strike breakdown. GET /v1/exposure/levels/{symbol} returns the flip, call wall and put wall. Full-chain GEX needs Growth. Free keys get 5 requests a day and single-expiry GEX on stocks, without the volatility endpoint.

Access. REST at lab.flashalpha.com with an X-Api-Key header, SDKs including Python, and an MCP server with 78 tools that follow each endpoint's plan gate. Standard plans cover personal and single-team internal use.

Alpha ($1,499/month) adds GET /v1/vrp/{symbol}, with put-wing and call-wing VRP, variance-space VRP, a GEX-conditioned harvest score, and historical replay from January 2017 where covered.

Where FlashAlpha is weaker. The volatility endpoint takes one symbol per request, and the screener covers a plan-limited symbol list. For a whole-universe IV/HV rank in one call, Alphanume is the direct tool.

Side by side

Neither standard plan permits redistribution.

Why the two IV/RV numbers will not match

Both vendors subtract realized from implied volatility. Five choices make the results differ for the same stock on the same day.

1. Which option supplies the IV. Alphanume uses one at-the-money call in the listed expiry nearest 30 calendar days and returns exp_date, days_to_exp and atm_strike. FlashAlpha's atm_iv also comes from a listed expiry. Neither is an interpolated constant-maturity IV30, so different expiries give different IVs.

2. The realized window. Alphanume uses 30 trading days of close-to-close returns. FlashAlpha returns 5, 10, 20, 30 and 60-session figures from log returns, sample standard deviation, annualized with √252. The closest match is rv_30d. The window can change the sign: with 30% IV, 22% 20-session RV and 35% 5-session RV, the 20-session spread is +8 points and the 5-session spread is -5.

3. Units. Alphanume returns annualized decimals (0.1795 is 17.95%), so its spreads need multiplying by 100. FlashAlpha returns percent, and spreads are already in volatility points.

4. What a rank means. Alphanume's iv_hv_ratio_ranked (0 to 1) compares a name with every other name that day. A 0.9 says richer than 90% of the universe, not high for that stock. FlashAlpha's historical_context compares a symbol with its own past.

5. When the value was known. An Alphanume row with is_final = 0 can change before the close, so backtests should use settled rows. FlashAlpha's live response is a reading at its as_of time; Alpha's historical host recomputes from archived inputs at a requested timestamp. See the historical methodology and VRP formulas.

A positive spread on either product is a description, not a trade signal. Neither includes bid-ask costs or assignment.

Worked example: AAPL in both APIs

Task: check whether AAPL's options are rich against realized volatility, then look at dealer positioning.

Alphanume. One request. The values follow the example in Alphanume's documentation.

curl "https://api.alphanume.com/v1/iv-hv-premium?ticker=AAPL&date=2026-06-12&only_final=true" \ -H "X-API-Key: alp_YOUR_KEY" 

{ "count": 1, "data": [ { "date": "2026-06-12", "ticker": "AAPL", "iv": 0.1795, "hv": 0.2333, "iv_hv_spread": -0.0538, "iv_hv_ratio": 0.769, "iv_hv_ratio_ranked": 0.31, "exp_date": "2026-07-17", "days_to_exp": 31, "atm_strike": 290, "spot": 291.36, "is_final": 1 } ] } 

IV 17.95% against 30-session HV 23.33% gives -5.38 volatility points. A rank of 0.31 means about 69% of the universe looked richer that day. The row has no skew, shorter window or positioning.

FlashAlpha. Two requests on Growth. Values are illustrative and trimmed; field names match the docs.

curl -H "X-Api-Key: YOUR_API_KEY" \ "https://lab.flashalpha.com/v1/volatility/AAPL" 

{ "symbol": "AAPL", "underlying_price": 291.36, "as_of": "2026-06-12T19:31:04Z", "atm_iv": 18.4, "realized_vol": { "rv_5d": 14.9, "rv_10d": 19.6, "rv_20d": 22.1, "rv_30d": 23.3, "rv_60d": 21.0 }, "iv_rv_spreads": { "vrp_5d": 3.5, "vrp_10d": -1.2, "vrp_20d": -3.7, "vrp_30d": -4.9, "assessment": "negative_spread" } } 

curl -H "X-Api-Key: YOUR_API_KEY" \ "https://lab.flashalpha.com/v1/exposure/gex/AAPL" 

{ "symbol": "AAPL", "underlying_price": 291.36, "gamma_flip": 287.5, "gamma_flip_status": "available", "net_gex": 412000000, "net_gex_label": "positive" } 

The 30-session spread is negative, matching Alphanume. The 5-session spread is positive because the last week was quieter than the month. Net GEX is positive with spot above the flip, usually read as dealers damping moves. That is context, not a forecast.

To compare the feeds in one notebook, convert units first:

alphanume_spread_pts = row["iv_hv_spread"] * 100 # -5.38 flashalpha_spread_pts = vol["iv_rv_spreads"]["vrp_30d"] # -4.9 gap = flashalpha_spread_pts - alphanume_spread_pts # ~0.5 

The half-point gap comes from the IV expiry and the return formula, not an error in either feed.

Who should pick which

• Backtesting a cross-sectional short-volatility sort: Alphanume. Settled daily rows with ready-made ranks are the input that study needs.
• Trading index or ETF options: FlashAlpha. IV/HV Premium covers equities, and the daily questions are gamma levels and RV windows on SPX, SPY or QQQ.
• Building watchlist alerts: FlashAlpha Growth. One key reads IV/RV, GEX and levels per symbol during the session.
• A solo quant wanting many event datasets on one bill: Alphanume Pro, annual.
• A small team sharing one subscription: FlashAlpha. Alphanume Pro is one named user.

Using both

The products sit at different steps. Alphanume narrows the market to a shortlist each day, for example min_ratio_rank=0.9 on settled rows. FlashAlpha then reads each name during the session: RV ladder, skew, net GEX and flip. Twenty names at two requests each is 40 requests, well inside Growth's quota.

To move IV/RV fields from Alphanume to FlashAlpha:

Going the other way, Alphanume replaces a loop of per-symbol vrp_30d calls with one whole-market request, at the cost of shorter windows, skew and GEX.

Sources

This comparison does not measure feed reliability or trading performance. The FlashAlpha responses above are illustrative.

• Alphanume: catalog, IV/HV Premium methodology, IV/HV Rank, API reference and MCP, pricing.
• FlashAlpha: volatility, GEX, levels, VRP, historical VRP, methodology, terms.

Related: 69 GEX and VRP APIs compared · Best VRP APIs. FlashAlpha plans are on the pricing page.