Options Snapshot API — FMV, Greeks, IV & OI

The core cvforge dataset is a live snapshot of every listed U.S. option contract — sourced from Massive’s options snapshot feed, ingested continuously, and refreshed in the serving database about once a minute. Each contract carries supported contract terms, Massive fair market value (FMV), Greeks, implied volatility, open interest, session aggregates, and the underlying’s price.

Pricing boundary: cvforge does not provide option bid/ask quotes, quote sizes, midpoint, NBBO, or last-trade data. fair_market_value is the only current per-contract valuation field. It is a proprietary estimate, not an executable quote, and must not be presented as one.

The /chains endpoint returns the full chain for one underlying, grouped by expiration and strike with calls and puts side by side — the natural shape for IV surfaces, Greeks ladders, skew charts, open-interest walls, and payoff tools. To filter across underlyings instead, use the screener; for free-form aggregation, use SQL.

Coverage

• Every optionable U.S. stock and ETF (the universe refreshes daily against the snapshot feed).
• Index options via the I: prefix: I:SPX, I:VIX, I:NDX, I:RUT, I:XSP.
• Open interest updates once daily after the close; FMV, Greeks, IV, and session data update with the snapshot.

Calling it

In an app built in cvforge (see the cvApi reference):

const data = await cvApi.chain('SPY');
// or pick exactly the fields you need:
const iv = await cvApi.chain('SPY', ['expiration_date', 'strike_price', 'contract_type', 'implied_volatility']);

Over REST — a GET with comma-separated params, or a POST with a JSON body:

curl -H "Authorization: Bearer cv_live_..." \
  "https://tap.convexvalue.com/api/data/chains/SPY?params=expiration_date,strike_price,contract_type,implied_volatility,delta,fair_market_value"

POST /api/data/chains
{ "symbol": "SPY", "params": ["expiration_date", "strike_price", "contract_type", "implied_volatility"] }

From a coding agent, the MCP tool is get_chain — see the MCP reference.

Request rules

• symbol: 1–24 characters, auto-uppercased; letters, digits, and . - / :.
• params: 1–32 supported field names from the table below (duplicates are dropped). Omitting fields in cvApi.chain() selects the supported default set.
• Responses include an x-cv-cache: hit|miss header; the GET form also sets Cache-Control: private, max-age=15, so browsers can re-render cheaply while staying fresh.

Response shape

Contracts are grouped by expiration, then strike. Each strike row is a compact triple: [strike, callValues, putValues], where the value arrays follow the order of your requested params (either side can be null if that contract doesn’t exist).

The values below illustrate the compact response shape; they are not a captured market response.

{
  "symbol": "SPY",
  "params": ["implied_volatility", "delta", "fair_market_value"],
  "chain": [
    {
      "expiration": "2026-07-17",
      "strikes": [
        [640.0, [0.22, 0.71, 18.42], [0.24, -0.29, 5.11]],
        [645.0, [0.21, 0.64, 14.96], [0.23, -0.36, 6.57]]
      ]
    }
  ],
  "contract_count": 12488,
  "elapsed_ms": 41
}

All 31 supported fields

Fields marked default are what you get when you don’t specify fields: contract_type, expiration_date, strike_price, implied_volatility, open_interest, delta, gamma, theta, vega, day_volume, underlying_price.

Identity

Contract terms

Pricing & valuation

Greeks

Day (session OHLCV)

Underlying

Metadata

Errors & limits

• 400 — unknown field name, empty/too-long params, or invalid symbol.
• 401 — missing or revoked API key.
• 429 — your plan’s hourly request limit is exhausted; it resets on the hour.