[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8},"actionData","errors","root",{"_28":-5,"_38":-5,"_39":40,"_41":42,"_43":44,"_45":46,"_47":48,"_49":50,"_51":52,"_53":54,"_55":56,"_57":58},"routes/_store+/_readers+/email_author.$slug/route",{"_9":10,"_11":-5},"book",{"_12":13,"_14":15,"_16":17,"_18":19,"_20":21,"_22":23},"currentUser","id","Z2lkOi8vbGVhbnB1Yi9TdG9yZTo6Qm9va1Byb2R1Y3QvNDY0Mzg","title","The Ultimate Guide to Outsourcing Your Auth","state","published","contactAuthorMethod","email","aboutText","

Almost every software application has users. In the online world, applications may have one or few users, if internal, or billions of users, if Facebook (hi Zuck!). Most applications customize functionality and the user interface for each user because of business rules or customer expectations.

Users are a fundamental entity. If you are building an application, you'll almost certainly have users. At FusionAuth, we've built a flexible auth system that makes managing users easy and secure. We talk to people about their auth systems every day and have helped plenty of folks migrate to FusionAuth from other systems, whether commercial, open source, or homegrown.

While modern auth systems can be quite complex, three pieces of functionality appear in almost every one: authentication, authorization and user management. When you are implementing an application, you can choose to build this functionality from scratch or use an existing auth system provider to outsource.

Much like you outsource your data management to a relational database system such as Postgresql, you can do the same with auth, with many of the same benefits.

This book will cover how to evaluate an auth system, risks you might encounter and how to mitigate them, and migration and implementation details.

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Kick off your book project, get started with GhostAI, get better at marketing, or spend the day doing all three! Free live workshops on Zoom. Saturday, June 27, 2026.

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