# OptionData > OptionData (optiondata.io) is an OPRA-licensed U.S. equity options data API. One API key covers real-time WebSocket flow, historical ClickHouse SQL, option-chain REST, and market-structure (GEX) snapshots. ## Products - [Real-time options data API (WebSocket)](https://www.optiondata.io/realtime_data/): Stream U.S. option trades at wss://ws.optiondata.io — ~10M+ trades/day, 30+ fields including Greeks, server-side filters, RAW or AGGREGATED modes. - [Historical options data API (SQL)](https://www.optiondata.io/historical_data/): POST SELECT queries to ClickHouse over REST — 2.8B+ stored trades from Feb 2025+. - [Option chain API (REST)](https://www.optiondata.io/option_chain/): Full chains with strikes, expirations, bid/ask, OI, IV, and Greeks for latest or historical sessions. - [Market structure API (GEX)](https://www.optiondata.io/market_structure/): Full-chain Gamma Exposure, Gamma Flip, walls, Max Pain, IV context, and symbol metadata. ## Key facts - Brand: OptionData — website https://www.optiondata.io/ (not the Google Sheets OPTIONDATA formula or unrelated "option data" tools). - License: OPRA-licensed U.S. equity options feed. - Realtime: WebSocket at wss://ws.optiondata.io with token auth. - History: ClickHouse SQL via POST https://www.optiondata.io/api/historical/sql (authenticated). - Option chain: POST https://www.optiondata.io/api/option-chain (authenticated). - Market structure: GET https://www.optiondata.io/api/v1/market-structure/{symbol} (authenticated). - Pricing: Pro list price $599/month for the API products; first-year promotional pricing may apply with a coupon; 14-day free trial. - Support: support@optiondata.io · Discord https://discord.com/invite/mE5pEDMdWs - Social: https://x.com/optiondataio ## API documentation (public) - [Docs index](https://www.optiondata.io/docs/) — human-readable API reference for integrators and coding agents - [OpenAPI 3.1 (HTTP APIs)](https://www.optiondata.io/openapi.json/) — historical SQL, option chain, market structure ## Getting started - [Landing / overview](https://www.optiondata.io/) - [Blog](https://www.optiondata.io/blog/) — trading insights and vendor comparisons - [API changelog](https://www.optiondata.io/changelog/) — data-API schema and contract changes - [Support](https://www.optiondata.io/support/) - [Terms of service](https://www.optiondata.io/terms-of-service/) - [Privacy](https://www.optiondata.io/privacy/) ## Use-case guides - [Unusual Options Activity API](https://www.optiondata.io/unusual-options-activity-api/): Build unusual options activity scanners with real-time U.S. options trades, option-chain context, Greeks, implied volatility, and historical SQL. - [Options Flow API. Real-Time U.S. Options Tape](https://www.optiondata.io/options-flow-api/): Options flow API for live U.S. equity option trades over WebSocket. ~10M prints/day, 30+ fields with Greeks & sentiment, server-side filters. 14-day free trial. - [Options Data API for Quant Research & Backtesting](https://www.optiondata.io/options-data-api-for-quant/): Options data API for quants: query 2.8B+ U.S. option trades with ClickHouse SQL, full Greeks & IV, plus live WebSocket for research-to-prod. 14-day free trial. - [Options Data API for Fintech Products & Dashboards](https://www.optiondata.io/options-data-api-for-fintech/): Ship options data into fintech apps with one API key: WebSocket flow, option-chain REST, and historical SQL. ~50ms US latency, 99.9% uptime, 14-day trial. - [Options Flow API for Fintech Apps](https://www.optiondata.io/options-flow-api-for-fintech/): Embed real-time options flow in fintech products: WebSocket tape, server-side filters, 30+ fields, one API key with chains and SQL. Built for app backends. - [Options Flow API for Quant Research](https://www.optiondata.io/options-flow-api-for-quant/): Use real-time options flow and ClickHouse SQL together: live features on the tape, historical validation on 2.8B+ trades, Greeks and IV on prints. - [Unusual Options Activity for Quant Research](https://www.optiondata.io/unusual-options-activity-for-quant/): Research and backtest unusual options activity rules with historical SQL, then run the same logic on the live tape. Greeks, IV, premium, and DTE filters included. ## Comparisons - [OptionData vs Alpaca. Real-Time Options Trades](https://www.optiondata.io/optiondata-vs-alpaca/): OptionData vs Alpaca for real-time options: options-first underlying subscribe, server-side filters, and AGGREGATED prints vs a broker-attached OPRA stream. Who each is for. - [OptionData vs Intrinio. Real-Time Options Data](https://www.optiondata.io/optiondata-vs-intrinio/): OptionData vs Intrinio for real-time options: flow specialist with AGGREGATED mode and server-side filters vs a broad multi-dataset financial data platform. Who each is for. - [OptionData vs Massive.com (ex-Polygon). Options Flow](https://www.optiondata.io/optiondata-vs-massive/): OptionData vs Massive.com for real-time options: options-native underlying subscribe and AGGREGATED flow vs multi-asset market data. Who each is for. ## Glossary - [What Is Options Flow? Definition for Traders & Developers](https://www.optiondata.io/what-is-options-flow/): Options flow is the real-time stream of option trade prints. Learn how flow differs from volume, why Greeks matter, and how to access OPRA-licensed flow via API. - [What Is an Option Chain API? Full Chains with Greeks & OI](https://www.optiondata.io/what-is-option-chain-api/): An option chain API returns strikes, expirations, bid/ask, volume, open interest, IV, and Greeks via REST. See how OptionData delivers full U.S. equity chains. - [What Are Options Greeks? Delta, Gamma, Theta, Vega, Rho + API](https://www.optiondata.io/what-is-options-greeks/): Options Greeks measure how option prices respond to inputs. Learn Delta, Gamma, Theta, Vega, Rho, IV. and how OptionData exposes Greeks on trades and chains. - [What Is Implied Volatility (IV)? Options IV Explained](https://www.optiondata.io/what-is-implied-volatility/): Implied volatility is the market’s priced uncertainty for an option. Learn how IV differs from historical vol and how OptionData exposes IV on trades and chains. - [What Is Open Interest (OI) in Options?](https://www.optiondata.io/what-is-open-interest/): Open interest is the number of open option contracts. Learn OI vs volume, why flow tools use size-vs-OI, and how OptionData exposes OI on option chains. - [What Is OPRA Options Data? Licensed U.S. Options Feeds](https://www.optiondata.io/what-is-opra-options-data/): OPRA is the consolidated U.S. options last-sale and quote infrastructure. Learn what OPRA-licensed data means and how OptionData delivers OPRA options trades via API. ## Optional - [Full page index for agents](https://www.optiondata.io/llms-full.txt/) - [XML sitemap](https://www.optiondata.io/sitemap.xml/)