> ## Documentation Index > Fetch the complete documentation index at: https://docs.heffl.com/llms.txt > Use this file to discover all available pages before exploring further. # Create a new invoice > Creates a new invoice with line items. Returns the invoice with calculated totals. ## OpenAPI ````yaml /openapi.json post /invoices openapi: 3.1.1 info: title: Heffl Public API (Legacy v1) version: 1.0.0 description: >- Legacy Heffl REST API v1. Maintained for existing integrations. For new projects, use API v2 at https://docs.heffl.com/api-v2/introduction. contact: name: Heffl Support url: https://heffl.com/support email: support@heffl.com servers: - url: https://api.heffl.com/api/v1 description: Production API Server security: - ApiKeyAuth: [] paths: /invoices: post: tags: - Invoices summary: Create a new invoice description: >- Creates a new invoice with line items. Returns the invoice with calculated totals. operationId: invoices.create requestBody: required: true content: application/json: schema: type: object properties: clientId: type: string description: Client public ID (required) date: type: string format: date-time x-native-type: date description: Invoice date dueDate: type: string format: date-time x-native-type: date description: Due date lineItems: type: array minItems: 1 items: type: object properties: name: type: string minLength: 1 description: Line item name productId: anyOf: - type: string - type: 'null' description: Product public ID (optional) quantity: type: number minimum: 0 default: 0 description: Quantity price: type: number minimum: 0 default: 0 description: Unit price description: anyOf: - type: string - type: 'null' description: Line item description taxRateId: anyOf: - type: string - type: 'null' description: Tax rate public ID discount: type: number minimum: 0 default: 0 description: Discount value discountType: enum: - fixed - percent default: fixed description: 'Discount type: fixed amount or percent' buyPrice: type: number minimum: 0 default: 0 description: Cost/buy price required: - name description: Invoice line items isInclusiveTax: type: boolean default: false description: Whether prices include tax status: enum: - DRAFT - SENT default: DRAFT description: Invoice status (DRAFT or SENT) contactId: anyOf: - type: string - type: 'null' description: Contact public ID subject: anyOf: - type: string - type: 'null' description: Invoice subject notes: anyOf: - type: string - type: 'null' description: Invoice notes salesPersonId: anyOf: - type: string - type: 'null' description: Sales person user public ID templateId: anyOf: - type: string - type: 'null' description: >- Document template public ID. If not provided, uses the team's default invoice template. tags: type: array items: type: number default: [] description: Tag IDs to associate with the invoice required: - clientId - date - dueDate - lineItems additionalProperties: {} responses: '200': description: OK content: application/json: schema: type: object properties: id: type: string description: Invoice public ID number: type: string description: Auto-generated invoice number date: type: string format: date-time x-native-type: date description: Invoice date dueDate: type: string format: date-time x-native-type: date description: Invoice due date status: type: string description: Invoice status clientId: anyOf: - type: string - type: 'null' description: Client public ID contactId: anyOf: - type: string - type: 'null' description: Contact public ID currency: type: string description: Currency code isInclusiveTax: type: boolean description: Whether prices include tax subject: anyOf: - type: string - type: 'null' description: Invoice subject notes: anyOf: - type: string - type: 'null' description: Invoice notes salesPersonId: anyOf: - type: number - type: 'null' description: Sales person user ID subTotal: type: number description: Subtotal before tax taxTotal: type: number description: Total tax amount discountTotal: type: number description: Total discount amount total: type: number description: Grand total pendingTotal: type: number description: Amount pending paidTotal: type: number description: Total amount paid lineItems: type: array items: type: object properties: name: type: string description: Line item name description: anyOf: - type: string - type: 'null' description: Line item description productId: anyOf: - type: number - type: 'null' description: Product ID quantity: type: number description: Quantity price: type: number description: Unit price tax: type: number description: Tax percentage discount: type: number description: Discount value discountType: enum: - fixed - percent description: Discount type buyPrice: type: number description: Cost/buy price viewType: enum: - LINE_ITEM - HEADING description: Line item type amount: type: number description: Line total after discount and tax taxAmount: type: number description: Tax amount for this line discountAmount: type: number description: Discount amount for this line required: - name - quantity - price - tax - discount - discountType - buyPrice - viewType - amount - taxAmount - discountAmount description: Invoice line items createdAt: type: string format: date-time x-native-type: date description: When the invoice was created customFields: anyOf: - type: object propertyNames: type: string additionalProperties: {} - type: 'null' description: Custom field values required: - id - number - date - dueDate - status - currency - isInclusiveTax - subTotal - taxTotal - discountTotal - total - pendingTotal - paidTotal - lineItems - createdAt components: securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: >- API key for authentication. Get yours at app.heffl.com/settings/developers ````