> ## Documentation Index > Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt > Use this file to discover all available pages before exploring further. # Retrieve calendars by identifier. > Use this operation to obtain holiday and business-day calendars needed for date calculations. Each supplied identifier is passed to the market-data lookup and all available calendars are returned. The request is read-only and does not create missing calendars. ## OpenAPI ````yaml /risk-and-pricing/atoti-risk-services/apis-endpoints/openapi/openapi.mintlify.json post /api/MarketData/GetCalendars openapi: 3.0.4 info: title: Derivitec Api 1.0 version: '1.0' servers: - url: https://api.riskportal.activeviam.com security: - oauth2: [] - apikey: [] tags: - name: AdminUser - name: AtotiReport - name: AtotiSession - name: BloombergOAuth - name: Bond - name: BondYieldCurvePage - name: BookAccess - name: Books - name: Commodity - name: Counterparties - name: Currencies - name: Equity - name: EquityDividend - name: EquityPage - name: FeatureFlag - name: Fx - name: FxPage - name: GroupAccess - name: Home - name: LegacyPosition - name: MarketData - name: MarketDataProvider - name: MarketDataProviderAccess - name: Meta - name: Notification - name: Organisation - name: PnLReport - name: PortfolioAccess - name: Portfolios - name: Position - name: PositionFilter - name: PricingEnvironment - name: PricingEnvironmentAccess - name: RateAsset - name: RateAssetPage - name: Report - name: ReportDefinition - name: ReportHistoryLauncherQuery - name: ReportLauncher - name: ReportQuery - name: ReportQueryViewUser - name: ReportRestriction - name: ReportView - name: RiskReport - name: Tradable - name: TradeBooking - name: User - name: VarReport - name: VarReportQuery - name: YieldCurvePage paths: /api/MarketData/GetCalendars: post: tags: - MarketData summary: Retrieve calendars by identifier. description: >- Use this operation to obtain holiday and business-day calendars needed for date calculations. Each supplied identifier is passed to the market-data lookup and all available calendars are returned. The request is read-only and does not create missing calendars. operationId: GetCalendars requestBody: description: >- The query payload containing a non-empty `Identifiers` collection of calendar names or identifiers recognised by the market-data service. content: application/json-patch+json: schema: $ref: '#/components/schemas/ApiGetCalendarsRequest' application/json: schema: $ref: '#/components/schemas/ApiGetCalendarsRequest' text/json: schema: $ref: '#/components/schemas/ApiGetCalendarsRequest' application/*+json: schema: $ref: '#/components/schemas/ApiGetCalendarsRequest' responses: '200': description: >- Returns all calendars found for the requested identifiers and any lookup errors. content: application/json: schema: $ref: '#/components/schemas/ApiGetCalendarsResponse' '400': description: BadRequest '401': description: Unauthorized '403': description: Forbidden security: - oauth2: [] - apikey: [] components: schemas: ApiGetCalendarsRequest: required: - $type type: object properties: identifiers: type: array items: type: string description: Calendar identifiers to retrieve. nullable: true $type: type: string enum: - >- Derivitec.Web.Core.MarketData.ApiGetCalendarsRequest, Derivitec.Web.Core additionalProperties: false description: Queries business-day calendars by calendar identifier. ApiGetCalendarsResponse: required: - $type type: object properties: is_success: type: boolean description: >- Whether the operation completed successfully. The default is `true`; error outcomes set it to `false`. example: true error_messages: type: array items: type: string description: >- Messages explaining operation-level failures. The collection is empty by default. nullable: true calendars: type: array items: $ref: '#/components/schemas/Calendar' description: Business-day calendars returned for the requested identifiers. nullable: true $type: type: string enum: - >- Derivitec.Web.Core.MarketData.ApiGetCalendarsResponse, Derivitec.Web.Core additionalProperties: false description: Returns the selected business-day calendars. Calendar: description: Named business-day calendar with holiday dates and weekend treatment. discriminator: propertyName: $type mapping: Derivitec.Web.Core.StaticData.Calendar, Derivitec.Web.Core: '#/components/schemas/CalendarMintlifyShape' Derivitec.Web.Core.StaticData.CalendarIntersection, Derivitec.Web.Core: '#/components/schemas/CalendarIntersection' Derivitec.Web.Core.StaticData.CalendarUnion, Derivitec.Web.Core: '#/components/schemas/CalendarUnion' oneOf: - $ref: '#/components/schemas/CalendarMintlifyShape' - $ref: '#/components/schemas/CalendarIntersection' - $ref: '#/components/schemas/CalendarUnion' CalendarMintlifyShape: required: - $type type: object properties: holidays: type: array items: type: string format: date-time description: Dates treated as holidays by the calendar. nullable: true include_weekends: type: boolean description: >- Whether weekend dates are included in the calendar's non-business-day set. name: type: string description: Name of the business-day calendar. nullable: true $type: type: string enum: - Derivitec.Web.Core.StaticData.Calendar, Derivitec.Web.Core additionalProperties: false description: Named business-day calendar with holiday dates and weekend treatment. CalendarIntersection: required: - $type type: object properties: holidays: type: array items: type: string format: date-time description: Dates treated as holidays by the calendar. nullable: true include_weekends: type: boolean description: >- Whether weekend dates are included in the calendar's non-business-day set. name: type: string description: Name of the business-day calendar. nullable: true calendars: type: array items: $ref: '#/components/schemas/Calendar' description: Gets or sets the list of underlying calendars in the intersection. nullable: true $type: type: string enum: - >- Derivitec.Web.Core.StaticData.CalendarIntersection, Derivitec.Web.Core additionalProperties: false description: The calendar intersection. CalendarUnion: required: - $type type: object properties: holidays: type: array items: type: string format: date-time description: Dates treated as holidays by the calendar. nullable: true include_weekends: type: boolean description: >- Whether weekend dates are included in the calendar's non-business-day set. name: type: string description: Name of the business-day calendar. nullable: true calendars: type: array items: $ref: '#/components/schemas/Calendar' description: Gets or sets the list of underlying calendars in the union. nullable: true $type: type: string enum: - Derivitec.Web.Core.StaticData.CalendarUnion, Derivitec.Web.Core additionalProperties: false description: The calendar union. securitySchemes: oauth2: type: oauth2 description: >- OAuth2 access-token requested from AWS Cognito and provided as a Auth Bearer header flows: implicit: authorizationUrl: https://auth.riskportal.derivitec.com/oauth2/authorize scopes: {} apikey: type: apiKey description: API-Key requested via the site and provided as a header name: x-api-key in: header ````