> ## Documentation Index > Fetch the complete documentation index at: https://docs.skylit.ai/llms.txt > Use this file to discover all available pages before exploring further. # Key levels (classified nodes) for one or more symbols > The strikes Skylit classifies as nodes (king, gatekeeper, pika, barney, significant) for up to 10 symbols, strongest first, with each level's distance from spot. Same live source, filters and 5-second cache as `/v1/heatmap`; 1 credit per request. ## OpenAPI ````yaml /openapi.yaml get /v1/gex/levels openapi: 3.1.0 info: title: Skylit Public API version: 1.0.0 summary: Options-Greeks heatmaps as a public HTTP API. description: | Skylit exposes its real-time options-Greeks (gamma / vanna) heatmaps as a versioned public HTTP API, per strike, with the live velocity metric and Skylit's node classification (King / Gatekeeper / etc.). **Authentication.** Send your Skylit API key as a bearer token: Authorization: Bearer A request without an `Authorization` header gets `401`; an invalid, revoked or expired key gets `403`. **Credit metering.** Every chargeable request debits a fixed cost from your credit balance: | Endpoint | Cost | |-----------------|-----:| | `/v1/heatmap` | 1 | | `/v1/historical` | 5 | | `/v1/stream` | 1 per minute open | | `/v1/openapi.json` | 0 | New customers are seeded with 5,000 credits. Every chargeable response carries `X-Credits-Remaining: `. Out of credits → `402` `insufficient_credits`; an admin-suspended account → `403` `account_suspended`. Top up via your account console. **Rate limits.** A safety ceiling of 600 requests / minute is enforced by the Skylit gateway and surfaced via `X-RateLimit-Limit`, `X-RateLimit-Remaining`, and `X-RateLimit-Reset`. `429` includes `Retry-After`. This is a runaway-protection ceiling, not a quota — credit metering does the per-customer accounting. Live streams (`/v1/stream`) cost 1 credit to open plus 1 per minute connected, and close after one hour. **Resolution.** The heatmap is a 1-second time series. Endpoints return the single snapshot nearest the requested instant — poll `/v1/heatmap` every 60-90s for live, or query `/v1/historical` at any minute boundary for a 1-minute replay grid (no server-side downsampling needed). **Velocity is live-only.** The `velocityPct` field is present on `/v1/heatmap` (live) and absent on `/v1/historical` (replay). **Response shape.** Success → `{ "data": ..., "meta": { ... } }`; errors → `{ "error": { "code": "...", "message": "..." } }`. camelCase throughout. `data.symbols` is always an array (one element per requested symbol), so a single-symbol call and a multi-symbol "Trinity" call share one shape. servers: - url: https://api.skylit.ai description: Production security: - bearerApiKey: [] tags: - name: Heatmap - name: Meta paths: /v1/gex/levels: get: tags: - Heatmap summary: Key levels (classified nodes) for one or more symbols description: | The strikes Skylit classifies as nodes (king, gatekeeper, pika, barney, significant) for up to 10 symbols, strongest first, with each level's distance from spot. Same live source, filters and 5-second cache as `/v1/heatmap`; 1 credit per request. operationId: getLevels parameters: - $ref: '#/components/parameters/Symbols' - $ref: '#/components/parameters/Metric' - $ref: '#/components/parameters/MaxStrikes' - $ref: '#/components/parameters/MaxExpirations' - $ref: '#/components/parameters/Expirations' responses: '200': description: Levels per symbol. content: application/json: schema: type: object properties: data: type: object properties: symbols: type: array items: type: object properties: symbol: type: string asOf: type: string format: date-time spot: type: number previousClose: type: number kingNode: description: >- The strongest king node, or null when none is classified. nullable: true allOf: - $ref: '#/components/schemas/Level' levels: type: array items: $ref: '#/components/schemas/Level' meta: $ref: '#/components/schemas/Meta' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '402': $ref: '#/components/responses/PaymentRequired' '404': $ref: '#/components/responses/NotFound' components: parameters: Symbols: name: symbols in: query required: true description: | One ticker, or a comma-separated list for a single cross-asset call (e.g. `SPY` or `SPY,SPX,QQQ`). Each is returned as an element of `data.symbols`. schema: type: string example: SPY,SPX,QQQ Metric: name: metric in: query required: false description: Which Greek exposure to return per strike. schema: type: string enum: - gamma - vanna default: gamma MaxStrikes: name: maxStrikes in: query required: false description: Maximum number of strikes around spot to return. schema: type: integer default: 92 minimum: 1 maximum: 400 MaxExpirations: name: maxExpirations in: query required: false description: | How many of the nearest expirations to net into each strike's `value`. Ignored when `expirations` is set. schema: type: integer default: 5 minimum: 1 maximum: 60 Expirations: name: expirations in: query required: false description: | Net each strike over exactly these expirations (`YYYY-MM-DD`, comma-separated) — one for a single-expiration heatmap (`2026-05-22`) or several for a custom set (`2026-05-22,2026-06-19`). Supersedes `maxExpirations`, and reaches any expiration the snapshot has, not just the nearest ones. Requested dates the symbol does not have are ignored; the `expirations` array in the response lists what was actually used. If none of them match, the response is `404` with `code: expiration_not_found` and the available dates in the message. On `/v1/heatmap`, expirations that have already expired are not available (they are trimmed from the live snapshot) — replay them with `/v1/historical` instead. schema: type: string example: '2026-05-22' schemas: Level: type: object required: - strike - value - nodeType - distancePct properties: strike: type: number value: type: number description: Net exposure at this strike for the selected metric. nodeType: type: string enum: - king - gatekeeper - pika - barney - significant distancePct: type: number description: Percent distance from spot (negative = below). Meta: type: object required: - metric - resolution - mode - cached properties: metric: type: string enum: - gamma - vanna resolution: type: string example: 1m mode: type: string enum: - live - historical cached: type: boolean description: True if served from the in-process cache. Error: type: object required: - error properties: error: type: object required: - code - message properties: code: type: string description: Stable, machine-readable error code. example: no_data message: type: string description: Human-readable explanation. responses: BadRequest: description: Request validation failed. content: application/json: schema: $ref: '#/components/schemas/Error' Unauthorized: description: Missing or invalid API key. content: application/json: schema: $ref: '#/components/schemas/Error' PaymentRequired: description: Out of credits (`insufficient_credits`). content: application/json: schema: $ref: '#/components/schemas/Error' NotFound: description: | Unknown symbol, no data available, or none of the requested `expirations` exist for the symbol (`code: expiration_not_found`). content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: bearerApiKey: type: http scheme: bearer description: | Skylit API key in the `Authorization` header (`Authorization: Bearer `). ````