Overview

This guide is for developers who connect an existing ERP, accounting or POS system to FAWTIR. It explains how to send invoices, credit notes and debit notes, how FAWTIR turns them into PINT-OM e-invoices delivered over Peppol, and how your system learns the outcome.

If you are new to Peppol, start with the Introduction. If you want to send a test invoice, go to the Quick start.

Contents

Section	What it covers
Introduction	What FAWTIR does, the three integration channels, and the architecture
Quick start	From onboarding to your first test invoice
Environments	TEST and production, base URLs and API versions
Authentication	API keys, OAuth clients, permissions and authentication errors
API reference	Every endpoint an integration uses, with examples
ERP data mapping	How your ERP fields map to PINT-OM, and the rules FAWTIR enforces
Invoice synchronization	Push, pull, retries, duplicates and reconciliation
ERP connector	Managed Pull: letting FAWTIR collect invoices from your ERP
Invoice lifecycle	Statuses, Peppol delivery, recipient responses and tax data reporting
Error reference	Every error code, what it means and what to do
Invoice corrections	Credit notes, debit notes and fixing rejected documents
Webhooks	Optional event notifications, and polling
Platform limits	Sizes, rate limits, precision, dates and numbering
TEST checklist	Scenarios to pass before you go live
Production go-live	Moving from TEST to production safely
Support and versioning	API versions, changes and how to get help
Official references	PINT-OM, Peppol and Oman Tax Authority sources
FAQ and glossary	Common questions and the terms used in this guide

How to read the rules in this guide

Rules in this guide come from four places. We label them so you know where each rule comes from:

• Regulation (OTA) a requirement of the Oman Tax Authority.
• PINT-OM rule a rule of the PINT-OM specification. These carry a rule ID such as IBR-079-OM.
• FAWTIR rule how the FAWTIR platform behaves.
• Recommendation our advice for building a reliable integration.

All company names, tax numbers, invoice numbers and credentials in the examples are fictitious.