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P21 Developer Reference

Welcome to the Epicor Prophet 21 developer reference. This site covers everything you need to build integrations, business rules, and customizations against P21.

What's Here

Quick Start

New to P21 development? Start here:

  1. Authentication & Sessions — Every API call requires a session or token. Start here.
  2. Which API to Use — Choose the right API for your use case.
  3. Common Services — Session management, the foundation of all API work.

P21 Extensibility at a Glance

Layer Tool Language Use When
Data access Data Services API Any Read-heavy queries, OData filtering
Entity CRUD Entity API Any Standard create/read/update for business records
Window automation Interactive API Any Automating P21 as if a user were operating it
Business services Transaction API Any Complex transactions, 500+ service coverage
In-process logic Business Rules C# Custom validation, calculations, event handling
Form customization Crystal Forms Crystal Invoice/report layout customization
Screen customization DynaChange Config Portal design, field customization

API Base URLs

API Base URL
Common Services https://{server}/uiserver0/ui/common/v1/
Interactive API https://{server}/uiserver0/ui/interactive/v1/
Transaction API https://{server}/uiserver0/ui/interactive/transaction/
Entity API https://{server}/api/entity/
Data Services https://{server}/api/dataservices/

Server URL

Replace {server} with your P21 server hostname. All paths are case-sensitive.

SDK Versions

Current SDK versions (as of this documentation):

Package Version
P21.Extensions.BusinessRule 25.2.25
P21.DomainObject 25.2.45
P21.Common 3.80.4
Target Framework net48 / net8.0