Best Authentication Libraries for React in 2026

There are many ways to add authentication to a React application, but they do not all solve the same problem.

Some are libraries that run as part of your application. Some give you a React SDK connected to a managed identity service. Others are complete identity servers that you deploy independently and connect to your React application.

This distinction matters because choosing an authentication library is rarely just about getting a login page working. The choice also determines where your identity layer lives, who operates it, how easily it can be shared across applications and APIs, which protocols you can use later, and how much control you retain as the system grows.

In this post, I will compare 9 options React developers are likely to encounter in 2026:

Better Auth, Auth.js, Clerk, Auth0, Supabase Auth, Keycloak, WSO2 Identity Server, ThunderID, and MSAL React.

A React authentication library can solve login for one application. The harder decision is whether authentication should remain part of that application or become a reusable identity layer shared by everything around it.

What are we comparing?​

The term "authentication library" is used quite loosely.

Better Auth and Auth.js are closest to what developers traditionally mean by a library. You install them into your application and operate the authentication backend as part of your own stack.

Clerk and Auth0 give you React SDKs, but authentication ultimately depends on identity services operated by those vendors.

Supabase Auth sits inside the broader Supabase application platform, although its authentication service can also be self-hosted.

Keycloak, WSO2 Identity Server, and ThunderID are standalone identity servers. The React SDK or OIDC client is only the application-facing part of a larger identity system.

MSAL React is slightly different again. It is a React library specifically for applications authenticating through Microsoft Entra ID.

For a React developer, however, all of them can appear during the same search: "What should I add to my React application for authentication?"

That is the scope I am using here.

Start with where identity will live​

Before comparing hooks, components, or quickstarts, I would first decide where you want identity to live.

For a small application, keeping authentication inside the application stack can be completely reasonable. There is less infrastructure to introduce, and a library can give you the functionality you need without operating a separate identity server.

The question becomes more interesting as the application grows.

Identity usually stops being a concern of one frontend. Multiple applications may need the same users. APIs need tokens. B2B customers may need their own organizations and administrators. Enterprise customers start asking for SAML or OIDC federation and SCIM provisioning. Agents and workloads may also need identities of their own.

At that point, identity increasingly becomes reusable infrastructure rather than application code.

Deployment matters as well.

A managed service removes much of the operational responsibility, but you accept the provider's deployment model, pricing, service boundaries, and commercial terms.

A self-hosted identity server gives you more control, but you are responsible for availability, upgrades, databases, security patches, backup and recovery, certificates, monitoring, and capacity.

These are different architectural choices, even when the React code needed to call signIn() looks very similar.

Here is the high-level comparison.

Product	Type	Deployment	React integration	Broader identity direction
Better Auth	Application authentication library	Runs with your application	First-party React client	Organizations, SSO and SCIM through framework/plugins
Auth.js	Application authentication library	Runs with your application/backend	React support through Auth.js/NextAuth model	Primarily application authentication
Clerk	Managed identity platform	SaaS	First-party React SDK and UI components	Organizations, SSO and enterprise features
Auth0	Managed identity platform	SaaS, with private deployment options at Enterprise level	First-party React SDK	Organizations, enterprise federation, SCIM and broader IAM
Supabase Auth	Authentication service within Supabase	Managed or self-hosted	supabase-js	Primarily application authentication
Keycloak	Open-source identity server	Self-hosted	OIDC / keycloak-js	Organizations, federation and broad IAM protocol support
WSO2 Identity Server	Open-source identity server	Self-hosted, while WSO2 Identity Platform is also available as SaaS and private cloud	First-party React SDK and components	Hierarchical B2B organizations, enterprise IAM and agent identity
ThunderID	Open-source identity stack	Self-hosted	First-party React SDK	Agent identity, GitOps, OUs and newer identity architectures
MSAL React	Microsoft client library	React application backed by Microsoft Entra ID	First-party React SDK	Determined by the connected Entra ID tenant

Better Auth​

Better Auth is a TypeScript authentication framework that runs with your application rather than requiring a separate hosted identity provider. Vercel acquired Better Auth in July 2026, with the project continuing as open source and framework-agnostic software.

For React, Better Auth provides a first-party client and can be used without Next.js. It has also expanded beyond basic login, with support around organizations, enterprise SSO, SCIM, OAuth and OpenID Connect provider functionality, and other authentication capabilities.

The more important distinction is architectural.

Better Auth makes authentication part of your application stack. This can work well when authentication belongs primarily to one application and you want to own the implementation and data rather than depend on a hosted identity service.

The trade-off becomes more visible later.

Once several applications, APIs, services, or organizations need to share the same identity layer, having authentication embedded inside one application architecture can become a constraint. You may eventually want identity to become its own independently operated and reusable component.

This is not necessarily a weakness in Better Auth itself. It is largely a consequence of choosing an application authentication library rather than a standalone identity platform.

Auth.js​

Auth.js, formerly NextAuth.js, has been widely used for authentication in Next.js applications. Maintenance of the project has now moved to the Better Auth team, with existing deployments continuing to receive maintenance while Better Auth is the recommended direction for many new applications.

Auth.js can be used outside Next.js, but its architecture remains closely associated with server-side authentication endpoints.

For a plain client-side React application, you therefore need a backend environment to host those authentication routes rather than treating Auth.js as a completely standalone SPA authentication package.

For an existing Auth.js application, there may be no reason to move simply because another project exists.

For a new plain React application, I would compare the additional backend integration with the alternatives before choosing it.

There is also the same longer-term architectural consideration as Better Auth. Authentication becomes part of your application stack. If identity later needs to be reused across multiple applications, APIs, or services, separating it into an independent identity layer becomes another architecture change you need to make.

Again, that does not make Auth.js a bad authentication library. It means you should understand whether you are solving application authentication or establishing an identity platform that other systems will eventually need to consume.

Clerk​

Clerk is a managed identity service with first-party React tooling. Its React SDK provides hooks together with prebuilt authentication and user-management components, and it also supports capabilities such as Organizations and enterprise SSO.

For a React application, this can reduce the amount of authentication infrastructure you need to build and operate.

The important architectural decision is what sits behind the SDK.

Clerk operates the identity service for you. This removes infrastructure work, but it also means your application's identity layer depends on Clerk's cloud service, pricing model, service boundaries, and feature tiers.

You therefore do not have the same deployment control as you would with an identity system that can also run inside your own infrastructure.

This may not matter for many applications. But if usage grows significantly, commercial terms become part of the architecture decision. The same applies if a future customer requires a deployment model that the service does not provide.

The React integration is therefore only one part of the decision. You are also choosing the cloud identity service behind it.

Auth0​

Auth0 provides a managed identity platform and a dedicated React SDK for single-page applications. It supports OAuth 2.0, OpenID Connect, enterprise federation, Organizations, SCIM, and a broad set of enterprise identity capabilities.

For most teams, Auth0 is consumed as a vendor-operated identity service.

That removes much of the infrastructure work from the application team, but the same general trade-off as Clerk applies: your identity layer depends on the provider's service, pricing model, deployment options, and feature tiers.

One correction is important here. Auth0 can no longer accurately be described simply as cloud-only. Its Enterprise offering includes private deployment options.

However, that remains different from downloading an open-source identity server and independently deciding where and how you want to operate it.

For React itself, the integration is established and straightforward. The more important question is whether the Auth0 service model fits the amount of deployment and commercial control you want over the identity layer.

Supabase Auth​

Supabase Auth is slightly different because authentication is part of the broader Supabase application platform.

The JavaScript SDK works with React and provides the common authentication capabilities expected for applications using Supabase. Supabase Auth can also be used independently and its Auth server can be self-hosted, so it would be incorrect to describe it simply as a cloud-only service.

If your application already uses Supabase and Postgres, keeping authentication within the same platform can remove integration work. Supabase Auth also integrates naturally with the database and Supabase's Row Level Security model.

The limitation appears when authentication starts becoming a broader identity problem.

Supabase Auth is primarily application authentication rather than a full IAM platform designed to become a shared identity layer across many applications, APIs, organizations, enterprise identity providers, administrators, agents, and other identity types.

That distinction may not matter when you are building one application.

But if identity later becomes infrastructure of its own, you may need to introduce a dedicated identity platform and move some of those responsibilities outside the application platform.

So for me, the first question with Supabase Auth is simple: are you choosing authentication for a Supabase application, or are you choosing the long-term identity layer for a broader system?

Those can eventually become two different requirements.

Keycloak​

Keycloak is an Apache 2.0 licensed open-source identity server and has been deployed in production for many years.

For a React application, developers can use the official keycloak-js adapter or a standard OpenID Connect client. The old react-keycloak project that still appears in many tutorials is archived, so it should not be treated as the current React integration path.

Keycloak supports OpenID Connect and SAML together with broader IAM capabilities. Its Organizations model has also continued to develop, and newer releases have added additional organization administration features while SCIM support is being introduced.

The main difference from application libraries is that Keycloak is already a standalone identity layer.

Multiple applications can use the same server, and identity does not need to be embedded into each application's backend architecture.

The trade-off is operations.

Running an identity server in production involves much more than starting the getting-started container. Availability, clustering, databases, upgrades, security patches, certificates, monitoring, backup, and disaster recovery all become your responsibility.

For organizations that already have the platform engineering capability and want an established open-source identity server, that may be an acceptable trade.

For a small application team primarily looking for an authentication library, it can be significantly more infrastructure than the original problem requires.

WSO2 Identity Server​

WSO2 takes a different approach because the identity layer can remain a standalone platform without forcing you into one deployment model.

For self-managed environments, WSO2 Identity Server provides the identity server that you can operate in your own infrastructure, including on-premises, Kubernetes, public cloud, private cloud infrastructure, and environments where direct control of the IAM runtime is required.

At the same time, WSO2 Identity Platform is also available as a multi-tenant SaaS service and as a WSO2-managed private cloud deployment.

This means the initial decision does not have to be "put authentication inside the application" versus "hand identity completely to a SaaS provider."

You can keep identity as an independently reusable platform and choose the operational model that fits the organization.

For a React developer, the application-facing experience still starts with a first-party SDK.

The WSO2 React SDK provides React-specific components and hooks, while Next.js has its own SDK rather than making plain React a secondary use case. This gives developers component-based authentication experiences without requiring every application to build authentication flows directly from OAuth or OpenID Connect primitives.

However, the reason to consider WSO2 Identity Server is not simply that it has a React SDK.

One area is B2B identity.

WSO2 models organizations hierarchically. An organization can contain child organizations, which can themselves contain further organizations, while applications, roles, and users can be managed and shared within that structure.

This matters for B2B SaaS applications where an organization is not simply another attribute attached to a user.

Another area is protocol depth.

WSO2 Identity Server supports OAuth 2.0, OpenID Connect, SAML, SCIM, and more advanced identity and authorization profiles. As application authentication expands into enterprise federation, provisioning, API authorization, delegation, or regulatory interoperability, the identity layer does not have to be replaced simply because the original React application has grown beyond login.

WSO2 has also introduced first-class identity management for AI agents.

Current releases can represent and manage agents independently, including lifecycle, authentication, authorization, ownership, and auditability. Newer releases also support delegated scenarios where agents need to act with authority originating from a human rather than simply receiving a permanently standing credential.

This is another example of why separating the identity layer from the application can matter. Humans, APIs, workloads, organizations, and agents can all eventually need to participate in the same identity architecture.

For a small React application that only needs login, much of this capability may be unnecessary.

But if you expect identity to become infrastructure shared across applications and APIs, or if you need B2B IAM, enterprise federation, self-managed deployment, SaaS, or private cloud without changing the fundamental identity architecture, WSO2 covers a wider deployment range than either application-embedded libraries or SaaS-only approaches.

ThunderID​

ThunderID is the newest identity server in this comparison, and its maturity should be understood in that context.

It is an Apache 2.0 licensed open-source identity stack built in Go. It uses a lightweight runtime and declarative resource configuration and has been designed around newer identity requirements involving humans, machines, workloads, and AI agents.

Its current capabilities include OAuth 2.1 and OpenID Connect, WebAuthn/passkeys, identity provider federation, organizational units and groups, authorization, verifiable credentials, and declarative YAML configuration suitable for GitOps workflows.

Like Keycloak and WSO2 Identity Server, ThunderID keeps identity outside the application.

A React application uses the identity service rather than making authentication part of the React application's own backend architecture. ThunderID also provides a first-party React SDK with components for application integration.

Where ThunderID differs is its design direction.

AI agents are modeled as identities rather than simply being represented as OAuth clients. The model covers registration, credentials, lifecycle, ownership, and delegated authority, allowing an agent to exist and be governed independently from the human, workload, or application that uses it.

ThunderID also puts more emphasis on declarative configuration and GitOps-style operation than traditional IAM products.

There is, however, an important maturity difference.

ThunderID is a much younger project than WSO2 Identity Server or Keycloak. It does not yet have the same production history, ecosystem depth, or operational track record of identity servers that have been deployed for many years.

That should remain part of the evaluation rather than being hidden behind a feature table.

If your requirement is an established enterprise IAM deployment today, maturity may carry more weight.

If you are evaluating an open-source identity foundation for newer architectures, particularly agent identity, workload identity, decentralized identity, post-quantum evolution, or GitOps-managed IAM, ThunderID takes a different architectural direction and is worth evaluating against those requirements.

MSAL React​

MSAL React is Microsoft's React authentication library for applications using Microsoft Entra ID.

This is different from Better Auth or Auth.js in one important way.

The identity system does not live inside your application. Microsoft Entra ID is already the standalone identity service, while MSAL React is the client library your React application uses to interact with it.

The architectural constraint is therefore not that authentication becomes part of your application stack.

The dependency is Microsoft Entra ID itself.

If your users, applications, and identity policies already live in Entra ID, MSAL React is the natural integration and there may be little reason to introduce another identity system.

If you want an identity layer that you can operate independently of Microsoft's cloud and licensing model, MSAL React does not provide that option because the SDK is specifically designed around Entra ID.

So this is less of a general authentication-library decision and more a question of whether Microsoft Entra ID is already the identity platform you have chosen.

Which one should you choose?​

For me, the useful distinction is not the React API. Most of these options can get a user signed in without much difficulty. The more important question is where you want the identity layer behind that React application to live as the system grows.

If authentication is primarily a concern of one application, libraries such as Better Auth or Auth.js can be a good fit. They keep authentication close to the application and give you control over the implementation. The thing to consider is whether identity is likely to remain an application concern. Once several applications, APIs, services, or organizations need the same identity context, separating identity from an individual application becomes increasingly useful.

Managed platforms such as Clerk and Auth0 already give you that standalone identity layer, but it is operated within the provider's service and deployment model. You gain operational simplicity, while accepting the provider's service boundaries, pricing, feature tiers, and deployment options.

Supabase Auth makes particular sense when Supabase is already part of your application architecture. If authentication later needs to become a broader IAM layer independent of that application platform, that is the point where its application-focused model needs to be reconsidered.

Keycloak gives you a standalone open-source identity server and full control over where you run it, but you also take on the operational responsibility of running identity infrastructure yourself.

WSO2 Identity Platform gives you another option. You can keep identity as a standalone reusable layer and choose how you want to operate it: self-managed through WSO2 Identity Server, as SaaS, or through a managed private cloud deployment. The React SDK remains the application-facing integration rather than becoming the identity architecture itself.

ThunderID follows the standalone identity model as well, with a newer architecture built around a lightweight Go runtime, declarative configuration, GitOps, and first-class support for newer identity types such as AI agents. It is also a much younger project, so maturity should remain part of that evaluation.

MSAL React is the more specific case. It makes sense when Microsoft Entra ID is already the identity platform you have chosen.

For a React developer, the login code is usually the easy part. The harder decision is where the identity layer behind it should live as the application grows.

For a single application, keeping authentication inside the application stack can be completely reasonable. A managed service can also be a good choice when you want to avoid operating identity infrastructure yourself. But once multiple applications, APIs, organizations, identity providers, or other identity types need to share the same identity context, authentication starts becoming a broader infrastructure concern.

You do not need to solve that problem on day one. But if you already know those requirements are coming, it is worth making that boundary explicit before choosing the library, because changing the React integration later is usually easier than changing the identity architecture behind it.