1. Invoice
HQ Rental Software
  • Getting started
  • Authentication
  • Base URLs, regions and versioning
  • Errors
  • Responses and pagination
  • HQ concepts and glossary
  • Custom fields and item types
  • Dates, time zones and money
  • Filtering and incremental sync
  • Guide: build a booking engine on your website
  • Guide: connect an OTA or broker
  • Guide: sync your fleet and prices to a website
  • Guide: sync invoices and payments to accounting
  • Guide: sync customers with a CRM
  • Guide: take payments
  • Guide: bill tolls and fines
  • Rate limits and idempotency
  • Webhooks
  • Car Rental
    • Comments
      • List the comments of a record
      • Create a comment
      • Update a comment
      • Delete a comment
      • List the comments of a reservation
      • Add a comment to a reservation
      • Delete a reservation comment
    • Currencies
      • List currencies
    • Emails
      • List email templates
      • Send an email template for a record
      • Send the reservation confirmation email
      • Send the rental agreement email
      • List the email templates of a reservation
      • Send an email template for a reservation
      • Create a quote and email it
    • Addresses
      • List the addresses of a record
      • Create an address
      • Get an address
      • Update an address
      • Delete an address
    • Fields
      • List the fields of a record type
      • Get a field by its column
      • List the customer form fields (booking step 5)
    • Blocked Days
      • List blocked days
    • Customer Credits
      • List the credit transactions of a customer
      • Add credit to a customer
      • Update a credit transaction
      • Delete a credit transaction
    • Fines
      • List fines
      • Create a fine
      • Get a fine
      • Update a fine
      • Delete a fine
    • Packages
      • List package items
      • Get a package item
      • List packages
      • Get a package
    • Quotes
      • List quotes
      • Get a quote
    • Rate Types
      • List rate types
      • Create a rate type
      • Get a rate type
      • Delete a rate type
      • Update a rate type
    • Rates
      • List rates
      • Create a rate
      • Get a rate
      • Delete a rate
      • List rates (v2)
      • Update a rate
    • Reservation Attempts
      • List reservation attempts
      • List reservation attempts by email
    • Extensions
      • List the extensions of a reservation
      • Extend a rental
      • Delete an extension
    • External Charges
      • List the external charges of a reservation
      • Add an external charge to a reservation
      • Delete an external charge
    • Adjustments
      • List the adjustments of a reservation
      • Add an adjustment to a reservation
      • Delete an adjustment
    • Payments
      • List the payments of a reservation
      • Record a payment on a reservation
      • Update a payment
      • Release an offline security deposit
      • Refund an online security deposit
      • Charge the customer's saved card
    • Refunds
      • List the refunds of a reservation
      • Record a refund on a reservation
      • Update a refund
    • Reservations
      • Confirm a reservation
      • Cancel a reservation
      • Set a reservation to pending
      • Set a reservation to quote
      • Mark a reservation as no-show
      • Mark a reservation as ready for pick-up
      • Get the options for the dates step (booking step 1)
      • Validate dates and list available vehicle classes (booking step 2)
      • Change the vehicle class of a reservation
      • List additional charges for a vehicle class (booking step 3)
      • Price a vehicle class with selected charges (booking step 4)
      • Create or update the booking customer (booking step 6)
      • Create the reservation (booking step 8)
      • Update a reservation
      • List reservations
      • Get the rental agreement link
      • Mark the rental agreement as signed
      • Get a reservation
      • Assign a vehicle to a reservation
      • Detach the vehicle from a reservation
      • List the vehicles available for a reservation
      • List the free vehicle class upgrades of a reservation
      • Apply a free vehicle class upgrade
      • Upload the driver signature
      • Upload pick-up or return photos
      • Search availability and prices for all vehicle classes
      • List reservations (API v2)
    • Vehicle Replacements
      • List the vehicle replacements of a reservation
      • Replace the vehicle of a rental
      • Delete a vehicle replacement
    • Reservation Agents
      • List the users that can be assigned as agents
      • Assign the agents of a reservation
      • Assign the return agents of a reservation
    • Seasons
      • List seasons
      • Create a season
      • Get a season
      • Update a season
      • Delete a season
    • Security Deposits
      • List security deposit rules
      • Get a security deposit rule
    • Availability
      • List availability of vehicle classes
      • Get availability of a vehicle class
    • Driver Licenses
      • Read a driver license barcode
      • Save a driver license barcode to a reservation customer
      • Upload a driver license image for a reservation customer
  • Filters
    • List filter types and operators
  • Contacts
    • List contact categories
    • Get a contact category
    • List contacts of a category
    • Create a contact
    • Get a contact
    • Update a contact
    • Merge contacts
  • Fleets
    • Additional Charges
      • List additional charges
      • Get an additional charge
    • Features
      • List features
      • Get a feature
    • Locations
      • List locations
    • Blocked Periods
      • List the blocked periods of a vehicle
      • Create a blocked period
      • Update a blocked period
      • Delete a blocked period
    • Branches
      • List vehicle makes
      • Get a vehicle make
      • List branches
    • Damages
      • List the damages of a vehicle
      • Create a vehicle damage
      • Get a vehicle damage
      • Update a vehicle damage
    • Vehicles
      • Models
        • List vehicle models
        • Get a vehicle model
      • Types
        • List vehicle types
        • Get a vehicle type
      • List the maintenance status of a vehicle
      • List vehicles
      • Get a vehicle
      • Update a vehicle
      • List vehicles for toll matching
    • Relocations
      • Create a relocation
      • Delete a relocation
      • List the relocations of a vehicle
    • Telematics
      • List the OBD readings of a vehicle
      • List OBD readings of all vehicles since a reading ID
      • List the telematics alerts of a vehicle
      • List the trips of a vehicle
      • List vehicle alert types
    • Maintenance
      • List repair orders
      • Create a repair order line
      • Update a repair order line
      • Delete a repair order line
      • Get a repair order
      • List maintenance types
    • Vehicle Classes
      • List vehicle classes
      • Get a vehicle class
  • Payment Gateways
    • List saved credit cards of a customer
    • Delete a saved credit card
    • List payment methods
    • Get a payment method
    • Get a payment button
    • Get a payment transaction by UUID
    • Create a payment transaction
    • Refund a payment transaction
    • Re-check a payment transaction
    • List payment transactions
  • Sheets
    • List sheet items
    • Create a sheet item
    • Get a sheet item
    • Update a sheet item
    • List sheets
    • Get a sheet
  • Files
    • List files of a record
    • Upload a file
    • Delete a file
  • Inventory
    • List inventory categories
    • Get an inventory category
    • Shows a list of inventory items
    • Finds inventory item by id
    • Finds inventory price by id
    • shows a list of inventory purchase order
    • Create purchase order
    • Finds purchase order by id
    • Returns report of purchase order
    • Cancels purchase order by id
    • Finds inventory stock by id
  • Invoice
    • List invoices available as e-invoices
      GET
    • Download e-invoices
      GET
    • Create invoice item
      POST
    • List invoice payments
      GET
    • Create an invoice payment
      POST
    • Get an invoice payment
      GET
    • Update an invoice payment
      PUT
    • Spread a payment over a contact's open invoices
      POST
    • List invoices
      GET
    • Create an invoice
      POST
    • Get an invoice
      GET
    • Email an invoice
      GET
    • Void an invoice
      POST
    • Download an invoice PDF
      GET
  • Audit Logs
    • Lists the audit log entries
  • Countries
    • List countries
  • Taxes
    • List taxes
    • Get a tax
  • Users
    • List users
  • Products
    • Categories
      • List product categories
      • Create a product category
      • Update a product category
      • Delete a product category
    • List products
    • Create a product
    • Update a product
    • Delete a product
  • Schemas
    • RequestBodies
    • Money
    • SaveRepairOrderLine
    • ErrorBusinessRule
    • SaveBlockedPeriod
    • ErrorValidation
    • SaveVehicleDamage
    • ErrorNotFound
    • ErrorUnauthorized
    • ReservationSummary
    • ReservationTotal
    • AvailableVehicleClass
    • AdditionalCharge
    • ReservationOverview
    • ReservationPayment
    • FleetsPageInfo
    • FleetsEmptySuccess
    • VehicleDamage
    • BillingAmount
    • InvoiceLine
    • ReservationRefund
    • CustomField
    • Comment
    • PaginationFields
    • Country
    • CustomFieldAddress
    • FilterDescriptor
    • Tax
    • VehicleClassAvailability
    • CustomerCreditTransaction
    • DriverLicenseData
    • DriverLicenseResult
    • Fine
    • FineInput
    • PackageItem
    • Package
    • Quote
    • RateType
    • RateTypeWrite
    • RatePriceInterval
    • RateRecord
    • RateWrite
    • ReservationAttempt
    • ReservationExtension
    • ReservationAdjustment
    • ReservationStatusResult
    • VehicleReplacement
    • ReservationRecord
    • ReservationListItem
    • ReservationListPage
    • ReservationDetail
    • ReservationOverviewWithVehicles
    • Season
    • SeasonWrite
    • SecurityDepositRule
    • OtaVehicleClassAvailability
    • RateV2
    • ReservationDriverV2
    • ReservationListItemV2
    • ContactCategory
    • Contact
    • ContactInput
    • AttachedFile
    • FleetAdditionalCharge
    • Branch
    • VehicleFeature
    • Location
    • VehicleMaintenanceStatus
    • RepairOrder
    • ObdReading
    • VehicleAlert
    • VehicleTrip
    • BlockedPeriod
    • VehicleMake
    • VehicleClassImage
    • VehicleClassFeature
    • VehicleClass
    • VehicleRelocation
    • VehicleType
    • Vehicle
    • InventoryCategory
    • InvoicePayment
    • Invoice
    • InvoiceDetail
    • SavedCreditCard
    • PaymentGatewaySummary
    • PaymentMethod
    • PaymentTransaction
    • ProductCategory
    • Product
    • SheetItem
    • SheetItemInput
    • Sheet
  1. Invoice

Spread a payment over a contact's open invoices

POST
/invoices/invoices/attach-payment
Records one payment from a contact and spreads it over that contact's unpaid invoices (status draft, sent or partial). Unpaid credit notes and refund documents can also receive part of it. Each invoice receives up to its unpaid amount until the payment is used up, and one payment record is created per invoice. The order in which invoices are filled is not guaranteed. Any amount left after every open balance is covered is not recorded.
Each invoice that receives a payment is recalculated: its status changes and the matching webhook fires, as in "Create an invoice payment". No payment email is sent and the payment is not added to a linked reservation.

Request

Authorization
Header Params

Body Params application/jsonRequired

Example
{
    "contact_type": "contacts",
    "contact_id": 30,
    "paid_on": "2026-10-06",
    "amount_paid": 100,
    "method": "bank",
    "notes": "Wire ref 4471",
    "accounting_account_id": 7
}

Responses

🟢200OK
application/json
The invoices that received part of the payment, under the invoices key, or [] when no invoice received anything. A successful body has no success field. HTTP 200 is also used for failures: such a body has success: false and is an ErrorUnauthorized (status_code 401 or 403).
Bodyapplication/json

Example
{
    "invoices": [
        {
            "id": 1024,
            "invoice_number": 1024,
            "prefix": "INV-",
            "full_number": "INV-001024",
            "uuid": "4b0d2f7e-8a51-4c3e-9f0a-2d6c1e9b7a35",
            "status": "paid",
            "type": "invoice",
            "issued_on": "2026-10-06T00:00:00.000000Z",
            "due_date": "2026-11-05T00:00:00.000000Z",
            "paid_on": "2026-10-06T00:00:00.000000Z",
            "po_number": "PO-7781",
            "currency": "usd",
            "contact_type": "contacts",
            "contact_id": 30,
            "label": "Jane Doe",
            "first_name": "Jane",
            "last_name": "Doe",
            "email": "jane.doe@example.com",
            "tax_id": 2,
            "tax_name": "Sales tax",
            "subtotal": "250.0000",
            "total_tax": "17.5000",
            "total_discount": "0.0000",
            "total_amount": "267.5000",
            "total_paid": "267.5000",
            "notes": "Thank you for your business.",
            "terms": "Payment due within 30 days.",
            "item_type": "car_rental.reservations",
            "item_id": 1052,
            "created_at": "2026-10-06T14:02:11.000000Z",
            "updated_at": "2026-10-06T15:20:43.000000Z"
        }
    ]
}
🟠422Parameter Error
Modified at 2026-10-29 13:52:44
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