> ## Documentation Index > Fetch the complete documentation index at: https://docs.kalshi.com/llms.txt > Use this file to discover all available pages before exploring further. # Decrease Order (V2) > Endpoint for decreasing the remaining count of an existing event-market order using the V2 request/response shape. Exactly one of `reduce_by` or `reduce_to` must be provided. ## OpenAPI ````yaml /openapi.yaml post /portfolio/events/orders/{order_id}/decrease openapi: 3.0.0 info: title: Kalshi Trade API Manual Endpoints version: 3.26.0 description: >- Manually defined OpenAPI spec for endpoints being migrated to spec-first approach servers: - url: https://external-api.kalshi.com/trade-api/v2 description: Production Trade API server - url: https://api.elections.kalshi.com/trade-api/v2 description: Production shared API server, also supported - url: https://external-api.demo.kalshi.co/trade-api/v2 description: Demo Trade API server - url: https://demo-api.kalshi.co/trade-api/v2 description: Demo shared API server, also supported security: [] tags: - name: api-keys description: API key management endpoints - name: orders description: Order management endpoints - name: order-groups description: Order group management endpoints - name: portfolio description: Portfolio and balance information endpoints - name: communications description: Request-for-quote (RFQ) endpoints - name: multivariate description: Multivariate event collection endpoints - name: exchange description: Exchange status and information endpoints - name: live-data description: Live data endpoints - name: markets description: Market data endpoints - name: milestone description: Milestone endpoints - name: search description: Search and filtering endpoints - name: incentive-programs description: Incentive program endpoints - name: fcm description: FCM member specific endpoints - name: events description: Event endpoints - name: structured-targets description: Structured targets endpoints paths: /portfolio/events/orders/{order_id}/decrease: post: tags: - orders summary: Decrease Order (V2) description: >- Endpoint for decreasing the remaining count of an existing event-market order using the V2 request/response shape. Exactly one of `reduce_by` or `reduce_to` must be provided. operationId: DecreaseOrderV2 parameters: - $ref: '#/components/parameters/OrderIdPath' - $ref: '#/components/parameters/SubaccountQueryDefaultPrimary' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/DecreaseOrderV2Request' responses: '200': description: Order decreased successfully content: application/json: schema: $ref: '#/components/schemas/DecreaseOrderV2Response' '400': $ref: '#/components/responses/BadRequestError' '401': $ref: '#/components/responses/UnauthorizedError' '404': $ref: '#/components/responses/NotFoundError' '500': $ref: '#/components/responses/InternalServerError' security: - kalshiAccessKey: [] kalshiAccessSignature: [] kalshiAccessTimestamp: [] components: parameters: OrderIdPath: name: order_id in: path required: true description: Order ID schema: type: string SubaccountQueryDefaultPrimary: name: subaccount in: query description: Subaccount number (0 for primary, 1-63 for subaccounts). Defaults to 0. schema: type: integer schemas: DecreaseOrderV2Request: type: object example: reduce_by: '2.00' exchange_index: 0 properties: reduce_by: $ref: '#/components/schemas/FixedPointCount' nullable: true description: >- String representation of the number of contracts to reduce by. Exactly one of `reduce_by` or `reduce_to` must be provided. reduce_to: $ref: '#/components/schemas/FixedPointCount' nullable: true description: >- String representation of the number of contracts to reduce to. Exactly one of `reduce_by` or `reduce_to` must be provided. exchange_index: allOf: - $ref: '#/components/schemas/ExchangeIndex' default: 0 x-go-type-skip-optional-pointer: true DecreaseOrderV2Response: type: object required: - order_id - remaining_count - ts_ms example: order_id: 3b23c1c7-f4ef-4f0d-8b9a-9e53c61f1a0d client_order_id: 8c35ecb3-328f-4f52-8c7c-0f4b9862f8d1 remaining_count: '8.00' ts_ms: 1715793680789 properties: order_id: type: string client_order_id: type: string remaining_count: $ref: '#/components/schemas/FixedPointCount' description: Number of contracts remaining after the decrease. ts_ms: type: integer format: int64 description: >- Matching engine timestamp at which the decrease was processed, as Unix epoch milliseconds. FixedPointCount: type: string description: >- Fixed-point contract count string (2 decimals, e.g., "10.00"; referred to as "fp" in field names). Requests accept 0-2 decimal places (e.g., "10", "10.0", "10.00"); responses always emit 2 decimals. Fractional contract values (e.g., "2.50") are supported; the minimum granularity is 0.01 contracts. example: '10.00' ExchangeIndex: type: integer description: >- Identifier for an exchange shard. Defaults to 0 if unspecified. Note: currently only 0 supported. example: 0 ErrorResponse: type: object properties: code: type: string description: Error code message: type: string description: Human-readable error message details: type: string description: Additional details about the error, if available service: type: string description: The name of the service that generated the error responses: BadRequestError: description: Bad request - invalid input content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' UnauthorizedError: description: Unauthorized - authentication required content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' NotFoundError: description: Resource not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' InternalServerError: description: Internal server error content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: kalshiAccessKey: type: apiKey in: header name: KALSHI-ACCESS-KEY description: Your API key ID kalshiAccessSignature: type: apiKey in: header name: KALSHI-ACCESS-SIGNATURE description: RSA-PSS signature of the request kalshiAccessTimestamp: type: apiKey in: header name: KALSHI-ACCESS-TIMESTAMP description: Request timestamp in milliseconds ````