API Reference Overview

The Ingest API is a single set of endpoints that serves four Billtrust products: Collections, Invoicing, Open Balance, and CashApp AR. The endpoints are the same regardless of which products are active — what changes is which fields you populate on each request.

Why Schemas Vary by Product

Each Billtrust product consumes data differently:

Product	What it does with the data
Collections	Manages the AR collections workflow — reminders, escalations, dispute tracking. Needs contact details, custom workflow fields, and multi-currency balance info.
Invoicing	Generates and delivers invoice PDFs to customers. Needs billing addresses, delivery routing, line items, and optional Thick Billing data for Billtrust-generated PDFs.
Open Balance	Provides a real-time balance snapshot for portal display and payment facilitation. Needs current denomination and optional payment templates.
CashApp AR	Matches incoming customer payments to open invoices. Needs invoice_num (required) and up to 22 custom matching fields to handle remittance data.

A field that is critical for one product may be completely ignored by another. For example:

• language is required for Collections (to translate reminder emails) but irrelevant to CashApp AR
• invoice_num is required for CashApp AR (payment matching engine) but optional for Collections
• Custom fields (custom_fields.collections.*) are Collections-only and never processed by Invoicing or Open Balance
• Thick Billing data elements only apply to Invoicing, specifically for Billtrust-generated PDFs

This means you only need to send the fields your active products actually use. Sending extra fields for inactive products is harmless — they are ignored — but the schemas document exactly which fields matter for each one.

Endpoints in This Section

Endpoint group	Description
Accounts	Create, replace, update, and retrieve customer accounts. Top-level resource — all other resources attach to an account.
Documents	Submit invoices and credit notes, manage document status, close documents, and list PDF attachments.
Representatives	Manage internal contacts used as escalation recipients in Collections workflows. Collections only.
Contacts	Manage supplementary contact details for an account used in Collections outreach. Collections only.
PDF Push	Upload PDF invoice files directly to the PDF Ingestion API for delivery.

Schema Reference

For the full field-level schema organized by product, see the Schemas section. Each product page lists only the fields relevant to that pipeline, so you can use it as a checklist when building your integration.