> ## Documentation Index > Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt > Use this file to discover all available pages before exploring further. # Calculate Billing > Calculate billing charges for a given period. Evaluates all active billing packages matching the specified type and returns transaction payloads ready for Midaz. All-or-nothing — if any package fails, no results are returned. ## OpenAPI ````yaml /en/openapi/v3-current/fees-engine.yaml post /v1/billing/calculate openapi: 3.1.0 info: title: Fees Engine description: '' version: 3.2.0 servers: - url: https://fees.sandbox.lerian.net security: [] tags: - name: Fees Engine paths: /v1/billing/calculate: post: tags: - Billing Calculation API summary: Calculate Billing description: >- Calculate billing charges for a given period. Evaluates all active billing packages matching the specified type and returns transaction payloads ready for Midaz. All-or-nothing — if any package fails, no results are returned. parameters: - $ref: '#/components/parameters/XOrganizationId' - $ref: '#/components/parameters/Authorization' - $ref: '#/components/parameters/ContentType' requestBody: content: application/json: schema: $ref: '#/components/schemas/CalculateBillingRequest' examples: volumeMonthly: summary: Monthly volume billing value: ledgerId: ldg_01HZ... period: 2026-03 type: volume maintenanceWeekly: summary: Weekly maintenance billing value: ledgerId: ldg_01HZ... period: 2026-W13 type: maintenance bothTypes: summary: Calculate all billing types value: ledgerId: ldg_01HZ... period: 2026-03 responses: '200': description: Billing calculation results with transaction payloads. content: application/json: schema: $ref: '#/components/schemas/CalculateBillingResponse' '400': description: '' content: application/json: schema: $ref: '#/components/schemas/Error' examples: Error0019: $ref: '#/components/examples/Error0019' Error0020: $ref: '#/components/examples/Error0020' Error0041: $ref: '#/components/examples/Error0041' Error0053: $ref: '#/components/examples/Error0053' Error0063: $ref: '#/components/examples/Error0063' '404': description: '' content: application/json: schema: $ref: '#/components/schemas/Error' examples: Error0059: $ref: '#/components/examples/Error0059' Error0061: $ref: '#/components/examples/Error0061' '422': description: Unprocessable — calculation failed due to dependency or data issues. content: application/json: schema: $ref: '#/components/schemas/Error' examples: Error0060: $ref: '#/components/examples/Error0060' Error0062: $ref: '#/components/examples/Error0062' Error0068: $ref: '#/components/examples/Error0068' '500': description: '' content: application/json: schema: $ref: '#/components/schemas/Error' examples: Error0004: $ref: '#/components/examples/Error0004' security: [] components: parameters: XOrganizationId: name: X-Organization-Id in: header description: The unique identifier of the Organization associated with the request. required: true schema: type: string example: 019c96a0-0a98-7287-9a31-786e0809c769 Authorization: name: Authorization in: header description: >- The authorization token in the 'Bearer ' format. **Important:** This header is required if your environment has Access Manager enabled. For more information, refer to the [Access Manager](/en/access-manager) documentation. required: false schema: type: string ContentType: name: Content-Type in: header description: The type of media of the resource. Must be `application/json`. required: true schema: type: string example: application/json schemas: CalculateBillingRequest: type: object properties: ledgerId: type: string description: Unique identifier of the Ledger to calculate billing for. period: type: string description: >- Billing period. Supported formats: `YYYY-MM` (monthly), `YYYY-Www` (weekly, e.g. `2026-W13`), or `YYYY-MM-DD` (daily). type: type: string enum: - volume - maintenance description: >- Filter by billing type. When omitted, both volume and maintenance packages are calculated. required: - ledgerId - period CalculateBillingResponse: type: object properties: results: type: array description: One result per active billing package processed. items: type: object properties: billingPackageId: type: string description: ID of the billing package that generated this result. billingPackageLabel: type: string description: Label of the billing package. billingType: type: string enum: - volume - maintenance description: Type of the billing package. period: type: string description: Billing period used for this calculation. totalAccounts: type: integer description: Total number of accounts evaluated. totalCharged: type: integer description: Number of accounts that were charged. totalSkipped: type: integer description: Number of accounts skipped (e.g., free-quota exhausted). totalNetAmount: type: string description: Net amount charged after discounts. Decimal string. transactionPayload: type: object description: >- Transaction payload ready to be sent to Midaz via POST /transactions/json. Includes audit metadata (billingPackageId, billingPeriod, pricing details) in the metadata field. summary: type: object description: Consolidated totals across all results. properties: totalResults: type: integer description: Number of billing packages processed. totalVolume: type: integer description: Number of volume results. totalMaintenance: type: integer description: Number of maintenance results. totalNetAmount: type: string description: Total net amount across all results. Decimal string. Error: type: object properties: code: type: string description: A unique, stable identifier for the error. title: type: string description: A brief summary of the issue. message: type: string description: Detailed guidance for resolving the error. required: - code - title - message description: The response message error. examples: Error0019: summary: Invalid header parameter value: code: FEE-0019 title: Invalid header parameter message: >- One or more headers parameters are in an incorrect format. Please check the following parameters and ensure they meet the required format before trying again. Error0020: summary: Missing header value: code: FEE-0020 title: Missing header message: >- Headers parameters is required. Please check the following header parameters %v and ensure they are passing the values correctly. Error0041: summary: Unmarshalling error value: code: FEE-0041 title: Unmarshalling error message: 'Invalid value for field ''%s'': expected type ''%s'', but got ''%s''.' Error0053: summary: Invalid billing type value: code: FEE-0053 title: Invalid billing type message: The type field must be `volume` or `maintenance`. Error0063: summary: Invalid period format value: code: FEE-0063 title: Invalid period format message: >- The period field must follow the format YYYY-MM (monthly), YYYY-Www (weekly), or YYYY-MM-DD (daily). Error0059: summary: Target account not found value: code: FEE-0059 title: Target account not found message: >- One or more accounts referenced in accountTarget could not be found in Midaz. Error0061: summary: No active billing packages value: code: FEE-0061 title: No active billing packages message: No active billing packages were found for the given ledger and period. Error0060: summary: Billing calculation failed value: code: FEE-0060 title: Billing calculation failed message: >- An internal error occurred while calculating billing for the given period. Error0062: summary: Segment resolution failed value: code: FEE-0062 title: Segment resolution failed message: >- The system could not resolve the segment referenced in waivedAccounts. Verify the segment ID and Midaz connectivity. Error0068: summary: Midaz query failed value: code: FEE-0068 title: Midaz query failed message: The system could not query Midaz. Verify connectivity and permissions. Error0004: summary: Internal Server Error value: code: FEE-0004 title: Internal Server Error message: >- The server encountered an unexpected error. Please try again later or contact support. ````