Developer guides for the Billabex API
Comprehensive tutorials covering authentication, pagination, rate limiting, and best practices for building integrations.
Getting Started
Quick introduction to the Billabex API. Learn how to authenticate and make your first API call.
Billabex OAuth Authentication
OAuth 2.1 Authorization Code flow with PKCE and optional OpenID Connect for Billabex.
OAuth Scopes
Understand available OAuth scopes, how access is enforced, and how to request the right permissions for your integration.
JSON Errors
Parse Billabex API errors by code, use the resolution hint, and retry only when the response allows it.
Billabex MCP Server
Connect AI tools to Billabex using the Model Context Protocol (MCP) with OAuth 2.1.
Notification Preferences
Read and update the authenticated user notification preferences.
Rate Limiting
Understand the OAuth token rate-limiting model, why it is designed this way, and what your integration should implement.
Audit Journal
Read who did what in an organization: one entry per successful command, filterable by account, actor and free text.
Pagination & Filtering
Understand Billabex cursor pagination and the filters parameter, and what your integration should implement.
Account Sources
Learn how to link and unlink external data sources to accounts via the API.
Original invoice of a credit note
Link a credit note to the invoice it came from, without creating an allocation or moving any balance.
Upsert Operations
Create or update resources in a single idempotent request using upsert endpoints.
Contacts
Manage customer contacts associated with accounts.
File Uploads
Upload invoice, credit note and email attachment files using binary or base64 encoding.
Account Tasks & Interactions
Respond to Billabex agent account tasks: search, list, get, cancel, set aside, and add user interactions.
Send an SMS or a letter
Preview, price, and send a paid follow-up without creating a duplicate.
Read the aging balance
Analyse net outstanding amounts by age bucket, currency, and customer account.
Not finding what you need?
Explore the complete API reference for detailed endpoint documentation, or reach out to our developer support team.