Best Options Flow API in 2026
If you want options flow data in your own code instead of a dashboard, the API matters more than the interface. Here is how the main options to choose between stack up.
Updated 2026-06-15 · 12 min read
Most market data APIs give you raw options trades and leave the hard part, turning prints into flow, to you. The Unusual Whales API is different: it exposes already-classified flow and unusual-activity endpoints, so you get sweeps, blocks, and alerts as data rather than building that pipeline yourself. If you would rather process raw OPRA prints from scratch, a feed like Polygon does that well. The choice comes down to how much of the flow logic you want to own.
- Raw options trade data is not the same as options flow. Flow is the classified, filtered view: sweeps, blocks, multi-leg, opening versus closing, unusual size relative to open interest.
- Some APIs hand you raw OPRA prints and expect you to build the classification. Others, like Unusual Whales, expose flow and flow-alert endpoints directly.
- The Unusual Whales API is GET-only with Bearer auth, has an OpenAPI spec, and returns JSON or Markdown.
- It also covers the data around flow, Greeks and GEX, dark pool prints, and chains, so you can enrich a flow signal without leaving the API.
- For real-time consumption, look at the streaming options: the API offers WebSocket channels and Kafka in addition to REST.
| Feature | Unusual Whales | Polygon.io | Raw OPRA feed |
|---|---|---|---|
| Pre-classified flow (sweep/block) | Yes | No (raw trades) | No (raw) |
| Unusual-activity / alert endpoints | Yes | No | No |
| Raw option trades | Yes | Yes | Yes |
| Greeks / GEX / IV endpoints | Yes | Partial | No |
| Dark pool in same API | Yes | No | No |
| Setup effort to get flow | Low | High (build it) | Very high |
| Streaming | WebSocket + Kafka | WebSocket | Direct feed |
Verified June 2026 from publicly available information. Confirm current features and pricing on each vendor's site.
1. Unusual Whales API
API from $150/mo ($125 annual); historical-data tiers from ~$249/moThis is our API. The reason to use it for flow specifically is that the classification is already done. Instead of ingesting every print and writing your own logic to detect sweeps and blocks, you call endpoints like /api/option-trades/flow-alerts and get the unusual activity as structured data. Around it sit the things you need to enrich a signal: Greeks, GEX, implied volatility, option chains, and dark pool prints, all in the same key. It is GET-only with Bearer auth, has an OpenAPI spec, and can return Markdown for LLM workflows. If you are building an agent rather than a classic bot, see our best market data API for AI agents guide.
- Pre-classified flow and unusual-activity endpoints, not just raw trades
- Greeks, GEX, IV, chains, and dark pool in the same API
- GET-only Bearer auth, OpenAPI spec, JSON or Markdown output
- WebSocket and Kafka streaming for real-time use
- Focused on U.S. equity options
- Historical depth and real-time access scale with the plan
2. Polygon.io
tiered plansPolygon gives you clean, reliable raw options trade and quote data with strong docs. If you want to own the flow logic, build your own sweep and block detection, and tune it exactly to your strategy, it is a solid foundation. The tradeoff is that the classification work is entirely on you, and there are no unusual-activity or dark pool endpoints. Compare directly on our Unusual Whales vs Polygon page.
- Clean raw options data
- Good documentation and SDKs
- No pre-classified flow or alerts
- You build all the flow logic yourself
Direct OPRA feed
Exchange fees ($$$)OPRA is the consolidated feed for U.S. options trades and quotes. It is the ultimate source, but it is a firehose with serious bandwidth, infrastructure, and exchange-fee requirements, and it gives you nothing pre-processed. It is the right answer for a firm building low-latency infrastructure and the wrong one for almost everyone else, who is better served by an API that has already done the ingestion.
- The raw, authoritative source
- Complete trade and quote data
- Heavy infrastructure and exchange fees
- Zero classification; you build everything
What is the difference between raw options data and options flow?
This is the distinction that decides which API you want. Raw options data is every trade and quote, as it prints. Options flow is the interpreted layer on top: which prints were sweeps, which were blocks, which opened a position versus closed one, and which were large relative to the existing open interest. For background on the concepts, see how to read options flow.
If an API only gives you raw trades, getting to flow means building a classification pipeline: detecting multi-exchange sweeps, grouping multi-leg orders, comparing size to open interest, and filtering out noise. That is real engineering, and keeping it accurate over time is ongoing work. An API that exposes flow directly hands you the output of that pipeline instead.
Should you build flow classification or use an API that has?
It depends on whether the classification is your edge or your overhead.
Build it yourself
If your strategy depends on a specific, proprietary definition of unusual, owning the logic on top of a raw feed like Polygon or OPRA gives you full control. You also take on the cost of building and maintaining it.
Use a flow API
If flow is an input to your strategy rather than the strategy itself, calling pre-classified endpoints is faster and less to maintain. You spend your time on the trading logic, not on rebuilding sweep detection. For most developers, this is the better trade.
What should you check before committing to a flow API?
- Is the flow pre-classified, or are you getting raw trades? This is the biggest single factor in your build effort.
- What surrounds it? Greeks, GEX, IV, chains, and dark pool data in the same API save you stitching together multiple vendors.
- How do you get real-time data? Check for WebSocket or streaming support, not just REST polling.
- Auth and docs. GET-only Bearer auth and a current OpenAPI spec make integration quick and keep an agent or codegen workflow simple.
- Historical depth and rate limits, matched to your plan and your use case.
Frequently asked questions
What is the best options flow API in 2026?+
For flow as ready-to-use data, the Unusual Whales API is the strongest option, because it exposes pre-classified flow and unusual-activity endpoints alongside Greeks, GEX, chains, and dark pool data. If you would rather process raw options trades and build your own classification, Polygon is a clean raw feed. A direct OPRA feed is only practical for firms with low-latency infrastructure.
Can I get options flow data through an API?+
Yes. The Unusual Whales API exposes options flow and unusual-activity endpoints, such as flow alerts, as structured data over GET requests with Bearer authentication. You can also retrieve raw option trades, Greeks, GEX, chains, and dark pool prints from the same API.
Do I have to build my own sweep and block detection?+
Not if you use an API that classifies flow for you. Raw feeds like Polygon or OPRA give you trades and leave the sweep, block, and multi-leg detection to you. The Unusual Whales API returns that classification already done, so you only build it yourself if you want a proprietary definition.
Does the options flow API support real-time data?+
Yes. In addition to REST endpoints, the Unusual Whales API offers WebSocket channels and Kafka streaming for real-time flow, alerts, prices, and halts, so a bot can react to activity as it happens rather than polling.
How much does an options flow API cost?+
It varies by provider and plan. The Unusual Whales API starts at $150 a month ($125 billed annually) as of June 2026, with higher historical-data tiers from around $249 a month. Raw feeds price separately, and a direct OPRA feed carries substantial exchange and infrastructure costs. Confirm current pricing on each provider's site.
Get options flow as data, not a pipeline
Read the API docs and grab a token to pull pre-classified flow, Greeks, and dark pool data straight into your code.