Invoice System

Create professional invoices from time entries, track payments, and manage your billing.

Overview

The invoice system includes:

Create invoices manually or from time entries
Professional PDF generation
Email invoices to clients
Track payment status
Multiple currencies
Tax calculations

Creating Invoices

Manual Invoice

Navigate to Agency OS → Invoices
Click New Invoice
Select Client from dropdown
Enter invoice details:
- Invoice Number - Auto-generated or custom
- Issue Date - Today's date
- Due Date - Payment deadline
- Currency - USD, EUR, GBP, etc.
Add line items or import from time entries
Click Create Invoice

From Time Entries

The fastest way to bill clients:

Go to Agency OS → Invoices
Click Create from Time Entries
Select client
Choose unbilled time entries:
- Filter by project or date range
- Select individual entries or bulk select
- Preview total before creating
Invoice auto-populates with selected entries
Adjust details and Create Invoice

        POST /wp-json/agency-os-ai/v1/invoices
{
  "client_id": 15,
  "invoice_number": "INV-2026-0042",
  "issue_date": "2026-03-31",
  "due_date": "2026-04-15",
  "currency": "USD",
  "items": [
    {
      "description": "Website Design - 8 hours",
      "quantity": 8,
      "rate": 150,
      "time_entry_ids": [12, 15, 18]
    }
  ]
}
    

Invoice Fields

Field	Type	Description
invoice_number	string	Unique invoice identifier
client_id	integer	Bill to client
project_id	integer	Related project (optional)
issue_date	date	Invoice date
due_date	date	Payment due date
status	enum	draft, sent, paid, overdue, cancelled
subtotal	decimal	Before tax
tax_rate	decimal	Tax percentage
tax_amount	decimal	Calculated tax
total	decimal	Final amount due
paid_date	date	Date payment received

Invoice Statuses

Status	Description
draft	Not yet sent to client
sent	Emailed to client, awaiting payment
paid	Payment received in full
overdue	Past due date, payment not received
cancelled	Invoice cancelled

Line Items

Each invoice contains line items:

Field	Type	Description
description	string	Service description
quantity	decimal	Hours or units
rate	decimal	Price per unit
amount	decimal	quantity x rate
time_entry_ids	array	Linked time entries

Emailing Invoices

Send invoices directly to clients:

Open invoice
Click Send Invoice
Review email preview
Click Send

The email uses the invoice template configured in Agency OS → Email Templates.

Payment Tracking

Record payments received:

Open paid invoice
Click Mark as Paid
Enter payment date and method
Invoice status updates to "paid"

API Endpoints

GET /wp-json/agency-os-ai/v1/invoices

List invoices. Params: client_id, status, from_date, to_date

POST /wp-json/agency-os-ai/v1/invoices

Create new invoice.

POST /wp-json/agency-os-ai/v1/invoices/create-from-time-entries

Create invoice from selected time entries.

POST /wp-json/agency-os-ai/v1/invoices/{id}/send

Email invoice to client.