> ## Documentation Index > Fetch the complete documentation index at: https://docs.gammaflip.io/llms.txt > Use this file to discover all available pages before exploring further. # What history exists > Per exchange and symbol: first and last capture, number of sessions and the date range of the daily files. **Free**: not counted against the quota. Cached for up to an hour. ## OpenAPI ````yaml /openapi.yaml get /history/coverage openapi: 3.1.0 info: title: GammaFlip GEX API version: 1.0.0 description: > Programmatic access to Gamma Exposure (GEX) data for crypto options (Bybit, Deribit, OKX, Derive) and US options (the `tradfi` exchange). API access is a plan entitlement (`api_access`). The trial includes it (50 requests/day); other plans with API access get 500 requests/day. Only `/gex/...`, `/levels/...` and the `/history/...` query endpoints count against the quota; `/exchanges`, `/coins`, `/expirations/...`, `/me` and `/history/coverage` are free. History file downloads use a separate daily bucket of file credits (trial 20, other plans 200). A `429` carries no `Retry-After` header: use `X-RateLimit-Reset`, `X-History-Files-Reset` or `/me`. All GEX values are USD per 1% move of the underlying. Field definitions: https://docs.gammaflip.io/data-dictionary contact: name: GammaFlip Support email: admin@gammaflip.io url: https://gammaflip.io servers: - url: https://api.gammaflip.io/api/v1 description: Production security: - ApiKeyAuth: [] paths: /history/coverage: get: tags: - History summary: What history exists description: > Per exchange and symbol: first and last capture, number of sessions and the date range of the daily files. **Free**: not counted against the quota. Cached for up to an hour. operationId: getHistoryCoverage responses: '200': description: Coverage content: application/json: schema: type: object required: - data - meta properties: data: type: array items: $ref: '#/components/schemas/HistoryCoverageRow' meta: type: object properties: timestamp: type: string format: date-time '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' components: schemas: HistoryCoverageRow: type: object properties: exchange: type: string example: tradfi symbol: type: string example: QQQ first_ts: type: string format: date-time example: '2026-05-04T13:30:00Z' last_ts: type: string format: date-time example: '2026-10-06T09:45:00Z' sessions: type: integer example: 109 files_first_date: type: - string - 'null' format: date example: '2026-05-04' files_last_date: type: - string - 'null' format: date example: '2026-10-05' Error: type: object description: > Standard error body. `error` is a stable slug safe to branch on; `message` is human-readable prose that may change and must not be parsed. Errors are never wrapped in the data/meta envelope used by successful responses. Some errors add hint fields. required: - error - message properties: error: type: string enum: - unauthorized - subscription_required - market_not_in_plan - rate_limit_exceeded - invalid_exchange - invalid_pair - invalid_expiration - invalid_param - no_data - unsupported_coin - market_unavailable - history_not_available - range_too_large - no_snapshot - no_file - files_unavailable - history_files_limit_exceeded - method_not_allowed example: invalid_exchange message: type: string example: Exchange 'kraken' is not available. current_tier: type: string description: With `subscription_required` and `market_not_in_plan`. example: trial valid_exchanges: type: array items: type: string description: With `invalid_exchange`, `invalid_pair` and `history_not_available`. example: - deribit - bybit - okx - derive - combined nearest_expirations: type: array items: type: string description: >- With `invalid_expiration`; up to five ISO dates closest to the request (the earliest five if the value is not a date). example: - '2026-10-17' - '2026-10-19' valid_values: type: array items: type: string description: >- With `invalid_param` for `view`, `granularity`, `file` and `compare`. example: - full - levels max_value: type: number description: With `invalid_param` for `range_pct`. example: 50 max_window_days: type: integer description: With `range_too_large`. example: 31 nearest_timestamps: type: array items: type: string format: date-time description: With `no_snapshot`; up to three capture times closest to `at`. example: - '2026-10-05T20:15:00Z' - '2026-10-05T13:45:00Z' market: type: string description: With `market_not_in_plan`; the market the requested coin belongs to. enum: - crypto - tradfi example: tradfi markets_in_plan: type: array items: type: string description: With `market_not_in_plan`. supported_crypto: type: array items: type: string description: >- With `unsupported_coin`; crypto coins listed by at least one exchange. example: - BTC - ETH - HYPE - SOL - XRP supported_tradfi: type: array items: type: string description: With `unsupported_coin`; US tickers we track. example: - QQQ - SPX - SPY rate_limit: allOf: - $ref: '#/components/schemas/RateLimit' description: >- With `rate_limit_exceeded` and `history_files_limit_exceeded`; mirrors the X-RateLimit-* headers. RateLimit: type: object properties: limit: type: integer example: 500 remaining: type: integer example: 487 reset: type: string format: date-time example: '2026-04-15T00:00:00+00:00' responses: Unauthorized: description: > Missing or invalid credential, or a credential that does not resolve to a user. Both return `unauthorized`. content: application/json: schema: $ref: '#/components/schemas/Error' Forbidden: description: > `subscription_required` (the plan has no API access) or `market_not_in_plan` (the plan does not include the coin's market). content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: ApiKeyAuth: type: apiKey in: header name: X-API-Key description: | API key prefixed with `gex_sk_`. Create one in your [account dashboard](https://gammaflip.io/account). ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.