HoneyBook Invoices API

openapi: 3.0.3
info:
  title: HoneyBook API (Modeled) Clients Invoices API
  description: HoneyBook does not publish a self-serve public developer API or a public API reference. This document models the logical resource surface implied by HoneyBook's product (clients/leads, projects, contracts, proposals, invoices, payments, scheduler sessions) and by the trigger/action events exposed through its Zapier integration (New Client, New Inquiry, Project Booked, Payment Received, Project Stage Changed). An internal API host, https://api.honeybook.com, is live behind Cloudflare and clearly backs HoneyBook's own web/mobile apps and its native integrations, but HoneyBook has never published endpoint documentation, a client registration/OAuth flow, or a field dictionary for outside developers. Third-party integration guides (e.g. Rollout) reference an OAuth 2.0 flow against api.honeybook.com and a `/v1/` base path, but are inconsistent with each other on the exact token endpoint and grant type, and are not independently verifiable - treat every path, parameter, and schema below as an honest, sourced-but-unverified model, not a confirmed reference. Confirm directly with HoneyBook before attempting integration.
  version: 1.0-modeled
  contact:
    name: HoneyBook
    url: https://www.honeybook.com
servers:
- url: https://api.honeybook.com/v1
  description: Modeled base path (unverified; not publicly documented by HoneyBook)
security:
- oauth2: []
tags:
- name: Invoices
  description: Invoices issued to clients within a project.
paths:
  /projects/{project_id}/invoices:
    parameters:
    - $ref: '#/components/parameters/ProjectId'
    get:
      operationId: listInvoices
      tags:
      - Invoices
      summary: List invoices for a project
      responses:
        '200':
          description: A list of invoices.
          content:
            application/json:
              schema:
                type: object
                properties:
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/Invoice'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
    post:
      operationId: createInvoice
      tags:
      - Invoices
      summary: Create an invoice for a project
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InvoiceInput'
      responses:
        '201':
          description: The created invoice.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Invoice'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
        '422':
          $ref: '#/components/responses/ValidationError'
  /invoices/{id}:
    parameters:
    - $ref: '#/components/parameters/Id'
    get:
      operationId: getInvoice
      tags:
      - Invoices
      summary: Retrieve an invoice
      responses:
        '200':
          description: The requested invoice.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Invoice'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
components:
  responses:
    Unauthorized:
      description: Missing or invalid access token.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: The requested resource was not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    ValidationError:
      description: The request payload failed validation.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  schemas:
    Invoice:
      allOf:
      - $ref: '#/components/schemas/InvoiceInput'
      - type: object
        properties:
          id:
            type: string
          project_id:
            type: string
          status:
            type: string
            enum:
            - draft
            - sent
            - paid
            - overdue
    InvoiceInput:
      type: object
      required:
      - amount_due
      properties:
        amount_due:
          type: number
        due_date:
          type: string
          format: date
        line_items:
          type: array
          items:
            type: object
            properties:
              description:
                type: string
              amount:
                type: number
    Error:
      type: object
      properties:
        error:
          type: object
          properties:
            code:
              type: string
            message:
              type: string
  parameters:
    Id:
      name: id
      in: path
      required: true
      description: The unique identifier of the resource.
      schema:
        type: string
    ProjectId:
      name: project_id
      in: path
      required: true
      description: The unique identifier of the parent project.
      schema:
        type: string
  securitySchemes:
    oauth2:
      type: oauth2
      description: Third-party integration guides reference OAuth 2.0 against api.honeybook.com, but are inconsistent on the exact token endpoint and grant type and are not independently verifiable. Modeled here as an authorization-code flow with refresh tokens, the most common pattern for a user-data platform of this kind; treat as unverified.
      flows:
        authorizationCode:
          authorizationUrl: https://api.honeybook.com/oauth/authorize
          tokenUrl: https://api.honeybook.com/oauth/token
          scopes:
            clients.read: Read clients and inquiries.
            clients.write: Create and update clients and inquiries.
            projects.read: Read projects and pipeline stage.
            projects.write: Create and update projects.
            contracts.read: Read contracts.
            contracts.write: Create contracts.
            proposals.read: Read proposals.
            proposals.write: Create proposals.
            invoices.read: Read invoices.
            invoices.write: Create invoices.
            payments.read: Read payments.
            scheduler.read: Read session types and bookings.
            scheduler.write: Create bookings.
            webhooks.write: Manage webhook subscriptions.
externalDocs:
  description: HoneyBook integrations and partnerships help center
  url: https://help.honeybook.com/en/collections/68941-integrations-and-partnerships