Invoices API

Name: Vantage PSA
Price: 49 USD
Author: Vantage

Invoices bill your clients for work performed. They can be created from time entries, fixed fees, retainer fees, or manual line items. Vantage handles PDF generation, email delivery, and payment tracking.

The Invoice Object

{
  "id": "inv_cuid123456",
  "invoice_number": "INV-2026-0042",
  "client_id": "cli_xxxxx",
  "contact_id": "con_xxxxx",
  "agreement_id": null,
  "status": "sent",
  "dates": {
    "invoice_date": "2026-01-25",
    "due_date": "2026-02-24",
    "sent_at": "2026-01-25T10:30:00Z",
    "viewed_at": "2026-01-25T14:15:00Z",
    "paid_date": null
  },
  "amounts": {
    "subtotal": 5000.00,
    "tax_rate": 0.0825,
    "tax_amount": 412.50,
    "total": 5412.50,
    "amount_paid": 0.00,
    "outstanding": 5412.50
  },
  "subject": "January 2026 Services",
  "notes": "Thank you for your business!",
  "internal_notes": "Rush project - expedited timeline",
  "po_number": "PO-12345",
  "payment": {
    "method": null,
    "reference": null
  },
  "pdf_url": "https://api.govantage.co/v1/invoices/inv_cuid123456/pdf",
  "reminders": {
    "last_reminder_at": null,
    "reminder_count": 0
  },
  "approval": {
    "required": false,
    "approved_at": null,
    "approved_by_id": null
  },
  "created_at": "2026-01-25T09:00:00Z",
  "updated_at": "2026-01-25T10:30:00Z"
}

Invoice Fields

Field	Type	Description
`id`	string	Unique identifier (prefix: `inv_`)
`invoice_number`	string	Auto-generated invoice number
`client_id`	string	Required. Associated client
`contact_id`	string	Billing contact
`agreement_id`	string	Retainer agreement (if applicable)
`status`	enum	Invoice status (see below)
`dates`	object	Important dates
`amounts`	object	Financial totals
`subject`	string	Invoice subject/title
`notes`	string	Notes visible to client
`internal_notes`	string	Internal notes (not on PDF)
`po_number`	string	Client’s purchase order number
`payment`	object	Payment details
`pdf_url`	string	URL to download PDF
`reminders`	object	Reminder tracking
`approval`	object	Approval workflow (if enabled)
`created_at`	datetime	When invoice was created
`updated_at`	datetime	When invoice was last updated

Invoice Status

Status	Description
`draft`	Not yet finalized
`pending_approval`	Awaiting internal approval
`approved`	Approved, ready to send
`sent`	Sent to client
`viewed`	Client has viewed
`partial`	Partially paid
`paid`	Fully paid
`overdue`	Past due date, unpaid
`void`	Cancelled/voided
`uncollectible`	Written off as bad debt

List Invoices

GET/v1/invoicesList all invoices

Returns a paginated list of invoices.

Query Parameters

Parameter	Type	Default	Description
`page`	integer	1	Page number
`per_page`	integer	20	Results per page (max: 100)
`client_id`	string		Filter by client
`status`	string		Filter by status (comma-separated)
`from`	date		Invoice date from
`to`	date		Invoice date to
`due_from`	date		Due date from
`due_to`	date		Due date to
`overdue`	boolean		Only overdue invoices
`search`	string		Search by number or subject
`sort`	string	`invoice_date`	Sort by: `invoice_date`, `due_date`, `total`, `status`
`order`	string	`desc`	Sort order: `asc`, `desc`

Request

curl "https://api.govantage.co/v1/invoices?status=sent,overdue&from=2026-01-01" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx"

Response

{
  "data": [
    {
      "id": "inv_cuid123456",
      "invoice_number": "INV-2026-0042",
      "client_id": "cli_xxxxx",
      "client_name": "Acme Corporation",
      "status": "sent",
      "dates": {
        "invoice_date": "2026-01-25",
        "due_date": "2026-02-24"
      },
      "amounts": {
        "total": 5412.50,
        "outstanding": 5412.50
      },
      "days_outstanding": 0
    }
  ],
  "pagination": {
    "page": 1,
    "per_page": 20,
    "total": 156,
    "total_pages": 8
  },
  "summary": {
    "total_invoiced": 125000.00,
    "total_outstanding": 45000.00,
    "total_overdue": 12500.00,
    "count_by_status": {
      "draft": 5,
      "sent": 12,
      "overdue": 3,
      "paid": 136
    }
  }
}

Create an Invoice

POST/v1/invoicesCreate a new invoice

Request Body

Field	Type	Required	Description
`client_id`	string	Yes	Client ID
`contact_id`	string	No	Billing contact ID
`agreement_id`	string	No	Retainer agreement ID
`invoice_date`	date	No	Invoice date (default: today)
`due_date`	date	No	Due date (default: invoice_date + payment_terms)
`subject`	string	No	Invoice subject
`notes`	string	No	Notes for client
`internal_notes`	string	No	Internal notes
`po_number`	string	No	PO number
`tax_rate`	decimal	No	Tax rate (e.g., 0.0825 for 8.25%)
`line_items`	array	No	Invoice line items

Line Item Object

Field	Type	Required	Description
`description`	string	Yes	Line item description
`quantity`	decimal	No	Quantity (default: 1)
`rate`	decimal	Yes	Unit rate
`amount`	decimal	No	Total (auto-calculated if not provided)
`time_entry_ids`	array	No	Time entries to include
`expense_ids`	array	No	Expenses to include

Request

curl -X POST "https://api.govantage.co/v1/invoices" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "client_id": "cli_xxxxx",
    "subject": "January 2026 Development Services",
    "invoice_date": "2026-01-31",
    "tax_rate": 0.0825,
    "line_items": [
      {
        "description": "Website Development - January 2026",
        "quantity": 32.5,
        "rate": 150.00
      },
      {
        "description": "Server Hosting (Monthly)",
        "quantity": 1,
        "rate": 250.00
      }
    ],
    "notes": "Thank you for your business!"
  }'

Response

{
  "data": {
    "id": "inv_cuid789012",
    "invoice_number": "INV-2026-0043",
    "client_id": "cli_xxxxx",
    "status": "draft",
    "dates": {
      "invoice_date": "2026-01-31",
      "due_date": "2026-03-02"
    },
    "amounts": {
      "subtotal": 5125.00,
      "tax_rate": 0.0825,
      "tax_amount": 422.81,
      "total": 5547.81,
      "amount_paid": 0.00,
      "outstanding": 5547.81
    },
    "line_items": [
      {
        "id": "line_xxxxx",
        "description": "Website Development - January 2026",
        "quantity": 32.5,
        "rate": 150.00,
        "amount": 4875.00
      },
      {
        "id": "line_yyyyy",
        "description": "Server Hosting (Monthly)",
        "quantity": 1,
        "rate": 250.00,
        "amount": 250.00
      }
    ],
    "created_at": "2026-01-25T10:30:00Z"
  }
}

Create from Unbilled Time

POST/v1/invoices/from-timeCreate invoice from unbilled time entries

Creates an invoice with line items automatically generated from unbilled time entries.

Request Body

Field	Type	Required	Description
`client_id`	string	Yes	Client ID
`from`	date	Yes	Time entries from date
`to`	date	Yes	Time entries to date
`project_id`	string	No	Filter to specific project
`group_by`	string	No	`none`, `project`, `ticket`, `user`, `date`
`include_expenses`	boolean	No	Include unbilled expenses

Request

curl -X POST "https://api.govantage.co/v1/invoices/from-time" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "client_id": "cli_xxxxx",
    "from": "2026-01-01",
    "to": "2026-01-31",
    "group_by": "project",
    "include_expenses": true
  }'

Response

{
  "data": {
    "id": "inv_cuid789012",
    "invoice_number": "INV-2026-0044",
    "amounts": {
      "subtotal": 8750.00,
      "total": 8750.00
    },
    "line_items": [
      {
        "description": "Website Redesign - Development Services",
        "quantity": 45.5,
        "rate": 150.00,
        "amount": 6825.00,
        "time_entry_count": 23
      },
      {
        "description": "Mobile App - Development Services",
        "quantity": 12.5,
        "rate": 150.00,
        "amount": 1875.00,
        "time_entry_count": 8
      },
      {
        "description": "Hosting fees (expense)",
        "quantity": 1,
        "rate": 50.00,
        "amount": 50.00,
        "expense_count": 1
      }
    ],
    "summary": {
      "time_entries_included": 31,
      "expenses_included": 1,
      "hours_billed": 58.0
    }
  }
}

Get an Invoice

GET/v1/invoices/:idRetrieve an invoice by ID

Path Parameters

Parameter	Description
`id`	The invoice ID

Query Parameters

Parameter	Type	Description
`include`	string	Comma-separated: `line_items`, `client`, `contact`, `time_entries`, `payments`

Request

curl "https://api.govantage.co/v1/invoices/inv_cuid123456?include=line_items,client" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx"

Update an Invoice

PUT/v1/invoices/:idUpdate an invoice

Only draft invoices can have amounts modified. Sent invoices can only update internal_notes and po_number.

Request

curl -X PUT "https://api.govantage.co/v1/invoices/inv_cuid123456" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "January 2026 Services - Updated",
    "notes": "Payment via ACH preferred"
  }'

Send an Invoice

POST/v1/invoices/:id/sendSend an invoice to the client

Sends the invoice via email and changes status to sent.

Request Body

Field	Type	Required	Description
`to`	array	No	Email addresses (defaults to billing contact)
`cc`	array	No	CC email addresses
`bcc`	array	No	BCC email addresses
`message`	string	No	Custom email message
`attach_pdf`	boolean	No	Attach PDF (default: true)

Request

curl -X POST "https://api.govantage.co/v1/invoices/inv_cuid123456/send" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "to": ["billing@acme.com"],
    "cc": ["john@acme.com"],
    "message": "Please find attached your invoice for January services."
  }'

Response

{
  "data": {
    "id": "inv_cuid123456",
    "status": "sent",
    "dates": {
      "sent_at": "2026-01-25T10:30:00Z"
    },
    "email_sent_to": ["billing@acme.com"]
  }
}

Record Payment

POST/v1/invoices/:id/paymentsRecord a payment

Request Body

Field	Type	Required	Description
`amount`	decimal	Yes	Payment amount
`date`	date	No	Payment date (default: today)
`method`	string	No	`credit_card`, `ach`, `check`, `wire`, `other`
`reference`	string	No	Payment reference/check number
`notes`	string	No	Payment notes

Request

curl -X POST "https://api.govantage.co/v1/invoices/inv_cuid123456/payments" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 5412.50,
    "date": "2026-02-15",
    "method": "ach",
    "reference": "ACH-789456"
  }'

Response

{
  "data": {
    "id": "inv_cuid123456",
    "status": "paid",
    "amounts": {
      "total": 5412.50,
      "amount_paid": 5412.50,
      "outstanding": 0.00
    },
    "payment": {
      "method": "ach",
      "reference": "ACH-789456"
    },
    "dates": {
      "paid_date": "2026-02-15"
    }
  }
}

Download PDF

GET/v1/invoices/:id/pdfDownload invoice PDF

Returns the invoice as a PDF file.

curl "https://api.govantage.co/v1/invoices/inv_cuid123456/pdf" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -o invoice.pdf

Send Reminder

POST/v1/invoices/:id/remindSend payment reminder

Sends a payment reminder email for overdue invoices.

curl -X POST "https://api.govantage.co/v1/invoices/inv_cuid123456/remind" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "message": "Friendly reminder that your invoice is now overdue."
  }'

Void an Invoice

POST/v1/invoices/:id/voidVoid an invoice

Voids the invoice and releases any associated time entries back to unbilled status.

Voiding an invoice with recorded payments is not allowed. Refund payments first.

curl -X POST "https://api.govantage.co/v1/invoices/inv_cuid123456/void" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "reason": "Duplicate invoice created in error"
  }'

Duplicate Invoice

POST/v1/invoices/:id/duplicateCreate a copy of an invoice

Creates a new draft invoice with the same line items.

curl -X POST "https://api.govantage.co/v1/invoices/inv_cuid123456/duplicate" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx"

Line Items

Add Line Item

POST/v1/invoices/:id/line-itemsAdd a line item

curl -X POST "https://api.govantage.co/v1/invoices/inv_cuid123456/line-items" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "description": "Additional development work",
    "quantity": 5,
    "rate": 150.00
  }'

Update Line Item

PUT/v1/invoices/:id/line-items/:line_idUpdate a line item

Delete Line Item

DELETE/v1/invoices/:id/line-items/:line_idRemove a line item

Aging Report

GET/v1/invoices/agingGet accounts receivable aging

curl "https://api.govantage.co/v1/invoices/aging" \
  -H "Authorization: Bearer vnt_sk_live_xxxxx"

Response

{
  "data": {
    "as_of": "2026-01-25",
    "total_outstanding": 85000.00,
    "buckets": {
      "current": 25000.00,
      "1_30_days": 35000.00,
      "31_60_days": 15000.00,
      "61_90_days": 5000.00,
      "over_90_days": 5000.00
    },
    "by_client": [
      {
        "client_id": "cli_xxxxx",
        "client_name": "Acme Corporation",
        "total": 15000.00,
        "current": 10000.00,
        "1_30_days": 5000.00
      }
    ]
  }
}

Webhooks

Subscribe to invoice events:

Event	Description
`invoice.created`	New invoice created
`invoice.sent`	Invoice sent to client
`invoice.viewed`	Client viewed invoice
`invoice.paid`	Invoice fully paid
`invoice.partial_payment`	Partial payment received
`invoice.overdue`	Invoice became overdue
`invoice.voided`	Invoice voided

Next Steps

Clients API - Manage client billing settings
Time Entries API - Log billable time
Agreements API - Manage retainers