> For the complete documentation index, see [llms.txt](https://fusionauth.io/docs/llms.txt)

# Identity Basics

Identity and access management is complex and can increase your risks if incomplete or wrong. Use this expert advice to help implement secure and efficient identity solutions for your applications.

# Identity Basics

![Identity Basics](https://fusionauth.io/img/icons/identity-basics.svg)

[!Optimizing Authorization Security: A Guide to Access Control Models Optimizing Authorization Security: A Guide to Access Control Models Exploring RBAC, ABAC, PBAC, and ReBAC as ways to model authorization in your system.](https://fusionauth.io/articles/identity-basics/authorization-models.md)

[!How Complete Does Your Authentication Provider Need To Be? How Complete Does Your Authentication Provider Need To Be? Learn the various types of authentication systems, advantages and limitations of each, and which ones might suit your application.](https://fusionauth.io/articles/identity-basics/complete-authentication-system.md)

[!Performing Due Diligence On Authentication Vendors Performing Due Diligence On Authentication Vendors What kind of due diligence should you do when evaluating identity as a service vendors?](https://fusionauth.io/articles/identity-basics/due-diligence-authentication-vendors.md)

[!Magic Links - A Guide to Passwordless Authentication Magic Links - A Guide to Passwordless Authentication Magic links offer secure, passwordless authentication, enhancing user experience and security. Learn more in and improve your access control today!](https://fusionauth.io/articles/identity-basics/magic-links.md)

[!Multi-Tenant vs. Single-Tenant IDaaS Solutions Multi-Tenant vs. Single-Tenant IDaaS Solutions Choosing between multi-tenant and single-tenant IDaaS solutions comes down to an organization's business objectives and requirements. Which trade-offs are you willing to make?](https://fusionauth.io/articles/identity-basics/multi-tenancy-vs-single-tenant-idaas-solutions.md)

[!Open Source vs. Commercial Auth Providers Open Source vs. Commercial Auth Providers A look at the pros and cons of open-source and commercial authentication providers.](https://fusionauth.io/articles/identity-basics/open-source-vs-commercial.md)

[!Why Outsource Your Auth System And How To Sell The Decision To Your Company Why Outsource Your Auth System And How To Sell The Decision To Your Company Why should you consider outsourcing your authentication, authorization and user management system, and how to get buy-in from your teammates.](https://fusionauth.io/articles/identity-basics/outsource-auth-system-blueprint.md)

[!User-Centric Security - How Passkeys Improve User Experience User-Centric Security - How Passkeys Improve User Experience We discuss the history of passkeys, how developers use them, and how they improve the overall user experience (UX) of application login.](https://fusionauth.io/articles/identity-basics/passkeys-ux.md)

[!Is Passwordless Authentication Ready for Regulatory Compliance? Is Passwordless Authentication Ready for Regulatory Compliance? Passwordless authentication methods, like passkeys, are all the rage. Does passwordless have a home in highly-regulated industries such as banking, healthcare, and local government?](https://fusionauth.io/articles/identity-basics/passwordless-regulatory-compliance.md)

[!Best Practices For Registration Forms Best Practices For Registration Forms Users have to fill out registration forms to access applications. How can you make this as painless as possible?](https://fusionauth.io/articles/identity-basics/registration-best-practices.md)

[!Slow Migration of User Data Slow Migration of User Data What is a slow migration and when does it make sense to perform one?](https://fusionauth.io/articles/identity-basics/slow-migration.md)

[!The Value of Trying Your Auth Provider Before You Commit The Value of Trying Your Auth Provider Before You Commit What are the benefits of trying an auth system provider before you integrate?](https://fusionauth.io/articles/identity-basics/try-before-you-buy.md)

[!What Is Identity Proofing? - Identity Verification Explained What Is Identity Proofing? - Identity Verification Explained Learn and how identity proofing helps verify a user's identity during onboarding. Understand common methods and its role in secure authentication systems.](https://fusionauth.io/articles/identity-basics/what-is-identity-proofing.md)

[!What Is OpenID Connect (OIDC) and How It Works What Is OpenID Connect (OIDC) and How It Works Explore OpenID Connect (OIDC) and understand how it enhances authentication for web and mobile applications. Learn its workings, benefits, and more.](https://fusionauth.io/articles/identity-basics/what-is-oidc.md)

[!What Is SCIM, The System For Cross-Domain Identity Management? What Is SCIM, The System For Cross-Domain Identity Management? What is SCIM, why would you use it, and how does it work?](https://fusionauth.io/articles/identity-basics/what-is-scim.md)

[!What To Do When Your Auth System Vendor Gets Acquired What To Do When Your Auth System Vendor Gets Acquired Authentication is an integral part of your application, and as such the acquisition of your auth vendor isn't like other acquisitions.](https://fusionauth.io/articles/identity-basics/what-to-do-when-auth-system-vendor-acquired.md)