# Overview
Short introduction and quick orientation for developers.
This documentation helps you set up, configure, and migrate DocCheck Login. It covers service basics, getting started with login clients and buttons, license information, available features, OAuth2 details, technical endpoints, and migration guidance from Legacy CReaM to the new system.
Use this page as an entry point to quickly find the right section for your task – whether you want to set up a new login, check an existing implementation, integrate OAuth2, or prepare your migration.
The table below gives quick entry points by topic.
| Topic | Content | Start |
|---|---|---|
| Introduction | Service purpose and architecture | Start |
| Getting started | Button, client setup, quickstart, passwords | Start |
| Licenses | Basic, Economy, Business | Start |
| Features | Personal, Deeplinks, Email‑domain whitelist, IP whitelist | Start |
| OAuth2 | Configuration, PHP Composer, Mobile Login | Start |
| Endpoints | Overview, access/refresh token, user data, errors | Start |
| Additional information | Guidelines, dos & don’ts, redirect & state flow | Start |
| Help | Feedback, contact | Start |