# API Reference

> Heatseeker heatmaps, Flowseeker options flow, Atlas price data and Tempest volatility as versioned HTTP APIs.

> **Beta.** The API and MCP server are open to members with API access. Check yours on the [Developer page](https://app.skylit.ai/developer).

The **Skylit Public API** gives you the data behind four Skylit modules. One API key and one credit balance work across all of them.

| API | What you get | Base URL | Reference |
|---|---|---|---|
| **Heatseeker** | Real-time options-Greeks (gamma / vanna) heatmaps per strike, live velocity, and Skylit's node classification (King, Gatekeeper, Pika, Barney, and more) | `https://api.skylit.ai` | [Heatseeker API](https://www.skylit.ai/docs/api-reference/heatmap/live-per-strike-heatmap-one-or-more-symbols) |
| **Flowseeker** | Options flow scored with Skylit's Flow Score, sweeps, flow tide and momentum, market-wide flow, dark-pool prints, and per-ticker and per-contract analytics | `https://api.skylit.ai` | [Flowseeker API](https://www.skylit.ai/docs/api-reference/flow/raw-flow-feed-for-a-ticker-flow-score-flowbonus-per-trade) |
| **Atlas** | OHLCV price bars and symbol search for charting | `https://atlas-api.skylit.ai` | [Atlas API](https://www.skylit.ai/docs/api-reference/history/ohlcv-price-bars-for-a-symbol-and-resolution) |
| **Tempest** | Skylit's volatility suite per symbol: implied volatility (SVX), term structure, expected-move cones, sigma moves, surface and skew, call/put premium tilt, event vol and VRP, the S&P volatility complex, a universe screener, daily history and a live stream | `https://api.skylit.ai` | [Tempest API](https://www.skylit.ai/docs/api-reference/tempest/every-tempest-module-per-symbol) |

### Heatseeker

- [Live heatmap](https://www.skylit.ai/docs/api-reference/heatmap/live-per-strike-heatmap-one-or-more-symbols): Current per-strike heatmap for one or more symbols, including live `velocityPct`.
- [Historical replay](https://www.skylit.ai/docs/api-reference/heatmap/replay-per-strike-heatmap-at-a-past-instant-one-or-more-symbols): The snapshot at or before any past instant, back to 2023-03-28.
- [Live stream (SSE)](https://www.skylit.ai/docs/api-reference/heatmap/live-sse-stream-up-to-10-symbols-per-connection): A Server-Sent Events feed of live heatmap updates, up to 10 symbols per connection.
- [Key levels](https://www.skylit.ai/docs/api-reference/heatmap/key-levels-classified-nodes-for-one-or-more-symbols): The strikes Skylit classifies as nodes, strongest first, with distance from spot.

### Flowseeker

- [Flow feed](https://www.skylit.ai/docs/api-reference/flow/raw-flow-feed-for-a-ticker-flow-score-flowbonus-per-trade): The latest options trades for a ticker, each with its Flow Score (-100 to +100) and FlowBonus.
- [Sweeps](https://www.skylit.ai/docs/api-reference/sweeps/aggregated-multi-exchange-sweep-activity): Multi-exchange sweeps grouped into logical orders, with venues, premium and Flow Score.
- [Market overview](https://www.skylit.ai/docs/api-reference/market/market-wide-flow-overview-for-the-current-trading-day): Market-wide flow for the current trading day, plus market tide and breadth.
- [Dark pool](https://www.skylit.ai/docs/api-reference/dark-pool/paginated-off-exchange-trf-prints): Off-exchange (TRF) prints and the largest dark-pool prints per ticker.

### Atlas

- [Price history](https://www.skylit.ai/docs/api-reference/history/ohlcv-price-bars-for-a-symbol-and-resolution): OHLCV bars for a symbol at any supported resolution.
- [Symbols](https://www.skylit.ai/docs/api-reference/symbols/resolve-a-symbol): Resolve and search the symbols Atlas serves.

### Tempest

- [Snapshot](https://www.skylit.ai/docs/api-reference/tempest/every-tempest-module-per-symbol): Every Tempest module for up to 10 symbols in one call.
- [Live stream (SSE)](https://www.skylit.ai/docs/api-reference/tempest/live-tempest-updates-server-sent-events): Tempest updates pushed as they are computed.
- [Expected-move cones](https://www.skylit.ai/docs/api-reference/tempest/expected-move-cones-per-symbol): Implied move ranges by horizon, per symbol.
- [Screener](https://www.skylit.ai/docs/api-reference/tempest/screen-the-whole-tempest-universe-radar): Screen the whole Tempest universe by volatility.

### For every API

- [Authentication](https://www.skylit.ai/docs/api-reference/authentication): Bearer API keys, credit metering, and rate limits.
- [Use it over MCP](https://www.skylit.ai/docs/mcp/overview): The endpoints are also MCP tools, so you can query them from Claude or Cursor in natural language, with the same key and credits.

## Base URLs

```bash
https://api.skylit.ai        # Heatseeker, Flowseeker and Tempest
https://atlas-api.skylit.ai  # Atlas
```

One base URL, `https://api.skylit.ai`, serves both Heatseeker and Flowseeker, so
an agent needs one host and one key for both. `https://flow-api.skylit.ai` is a
permanent alias for Flowseeker: same API, keys, limits and credits. Existing
integrations can keep using it.

The OpenAPI specs are served live by each API. Send your key with the request
(the Heatseeker spec needs none). Copies that need no key are at
`https://www.skylit.ai/docs/openapi.yaml`, `https://www.skylit.ai/docs/flowseeker-openapi.yaml`
and `https://www.skylit.ai/docs/atlas-openapi.yaml`.

| API | Spec |
| --- | --- |
| Heatseeker and Tempest (`/v1/vol/*`) | `https://api.skylit.ai/v1/openapi.json` |
| Flowseeker | `https://api.skylit.ai/v1/flow/openapi.json` |
| Atlas | `https://atlas-api.skylit.ai/v1/openapi.json` |

Building an agent? Read [Rate limits and retries](https://www.skylit.ai/docs/api-reference/rate-limits-and-retries)
and [Errors](https://www.skylit.ai/docs/api-reference/errors) before your first run.

## Quickstart

### 1. Get an API key

Generate a key on the [Developer page](https://app.skylit.ai/developer). New accounts
start with the credits their plan includes ([Plans and credits](https://www.skylit.ai/docs/api-reference/plans-and-credits)). New here? Follow
[Getting started for agentic traders](https://www.skylit.ai/docs/api-reference/getting-started).

### 2. Fetch a live heatmap

Pull the current per-strike gamma heatmap for SPY:

```bash cURL
curl "https://api.skylit.ai/v1/heatmap?symbols=SPY&metric=gamma" \
  -H "Authorization: Bearer YOUR_API_KEY"
```

```python Python
import requests

r = requests.get(
    "https://api.skylit.ai/v1/heatmap",
    params={"symbols": "SPY", "metric": "gamma"},
    headers={"Authorization": "Bearer YOUR_API_KEY"},
)
print(r.json()["data"]["symbols"][0]["strikes"][:3])
```

```javascript Node
const res = await fetch(
  "https://api.skylit.ai/v1/heatmap?symbols=SPY&metric=gamma",
  { headers: { Authorization: "Bearer YOUR_API_KEY" } },
);
const { data } = await res.json();
console.log(data.symbols[0].strikes.slice(0, 3));
```

### 3. Go cross-asset

Comma-separate symbols for a single **Trinity** call — `symbols=SPXW,SPY,QQQ` — and
each comes back as an element of `data.symbols`.

> **Warning:** For the S&P 500, request `SPXW`, not `SPX`. Index options are served per option root:
> `SPXW` holds every daily and weekly expiration (0DTE included) and is the board Trinity
> shows in the app, while `SPX` holds only the AM-settled monthlies, so its levels look
> very different. The same split applies to `NDXP` / `NDX` and `RUTW` / `RUT`.

### 4. Try Flowseeker and Atlas

The same key works on the other APIs:

```bash
# Latest scored options flow for SPY (1 credit)
curl "https://api.skylit.ai/v1/flow/SPY" \
  -H "Authorization: Bearer YOUR_API_KEY"

# SPY 1-minute price bars from Atlas (1 credit); from/to are Unix seconds
curl "https://atlas-api.skylit.ai/v1/history?symbol=SPY&resolution=1&from=1790602200&to=1790625600" \
  -H "Authorization: Bearer YOUR_API_KEY"
```

## How responses look

Every success returns a `data` / `meta` envelope; errors return an `error` object. Fields are camelCase.

```json
{
  "data": {
    "symbols": [
      {
        "symbol": "SPY",
        "asOf": "2026-05-22T14:31:00Z",
        "spot": 591.23,
        "strikes": [
          { "strike": 590, "value": 1894300.4, "nodeType": "king", "velocityPct": 12.4 },
          { "strike": 595, "value": 642100.2, "nodeType": "gatekeeper", "velocityPct": -3.1 }
        ]
      }
    ]
  },
  "meta": { "metric": "gamma", "resolution": "1m", "mode": "live", "cached": false }
}
```

- **Node types** (king · gatekeeper · pika · barney · significant · normal): Each strike carries Skylit's node classification — the same vocabulary used throughout [Patternpedia](https://www.skylit.ai/docs/patternpedia/pattern-the-whipsaw).
- **velocityPct** (live only): Present on `/v1/heatmap`; omitted on `/v1/historical` (velocity is a live metric).
- **Credits** (metered per request): `/v1/heatmap` costs 1 per call (one symbol or ten), `/v1/historical` costs 5, `/v1/stream` costs 1 per symbol to open plus 1 per symbol per minute. Each endpoint's price is on its reference page. Every response carries `X-Credits-Remaining`. See [Authentication](https://www.skylit.ai/docs/api-reference/authentication).