What is OpenID Connect (OIDC) and how does it work

Passwords are messy. VPNs break. SAML is a headache. Still, stuck with clunky login flows or apps that don’t talk to each other? It’s time to see what an OIDC identity provider (OIDC IdP) can do and why it’s becoming the backbone of modern Identity and Access Management.

OpenID Connect (OIDC) isn’t just another acronym; it’s built for speed, security, and scale.

That’s why more teams are moving to OIDC to connect to modernize identity and cut risk. Whether you’re managing thousands of endpoints or enabling hybrid users, OIDC gives you a cleaner, smarter way to control access.

Want to know what OIDC authorization is and how OIDC tokens work? You’re in the right place.

What is OpenID Connect (OIDC)?

OpenID Connect (OIDC) is a modern identity protocol. It helps users log in securely using one set of credentials across many apps and services.

Think of it as a secure translator between your app and an identity system. When a user logs in, OIDC authorization kicks in to confirm who they are. It then sends back an OIDC token that says, “This person is verified.”

OIDC sits on top of OAuth 2.0. While OAuth is about giving access to data, OIDC Connect is about logging in the user. It adds a layer of identity to the existing OAuth framework.

Here’s what makes OIDC specification important:

• It uses standard HTTPS and JSON, so it’s easy to work with.
• It’s widely supported by platforms like Google, Microsoft, and Apple.
• It works for mobile, cloud, and on-prem environments.

To understand how OpenID Connect (OIDC) works, you need to know the key pieces that make up the system. Here’s a breakdown of the main components in any OIDC configuration.

Key components of OIDC

1. Authentication: This is the core of it all. OIDC authorization starts when a user tries to log in. The system checks their identity and decides if access should be granted. It’s fast, secure, and built to reduce friction.

2. Client: The app or service the user wants to access. It could be a dashboard, SaaS tool, or mobile app. The client sends a login request to the OIDC identity provider and receives an OIDC token in return.

3. Relying party: Another name for the client. It “relies” on the OIDC IdP to authenticate users and verify identity.

4. Identity tokens: Once a user is authenticated, the IdP sends back an OIDC token, specifically an ID token. It includes user info like email, name, and login time, all in a secure format.

5. OpenID providers: Also called OIDC identity providers or IAM OIDC providers. These are trusted services (like Google, Azure AD, or Okta) that handle the actual login process and issue the identity tokens.

6. Users: These are your employees, partners, or customers. They log in through the client and get authenticated via the OIDC IdP. Once verified, they can access apps without needing to remember multiple passwords.

OpenID Connect vs OpenID 2.0

OIDC Connect simplifies the OIDC configuration, improves security, and supports the kind of modern apps your team actually uses. It gives you stronger control, smoother logins, and better support across platforms.

Why it matters: If your current setup still uses OpenID 2.0, you’re running outdated tech. That could leave you open to security issues, poor integration, and a bad user experience.

Bottom line: OIDC connect is not an update; it’s a full replacement.

What are OIDC flows?

OIDC flows are the different ways a user can be authenticated. Each flow is designed for a specific use case: web apps, mobile apps, APIs, or hybrids. At the heart of every flow is a simple goal: get the user authenticated, securely issue OIDC tokens, and give access without risking credentials.

Your IAM OIDC provider will help choose the right flow based on your architecture. Get that choice right, and you’ll lock down logins without slowing down users.

1. Authorization code flow

Authorization Code = secure and preferred

This is the most common flow, and the most secure. Here’s how it works:

• The user clicks “Log In.”
• The app redirects them to the OIDC identity provider (OIDC IdP).
• After login, the IdP sends an authorization code back to the app.
• The app exchanges that code for an OIDC token (ID + access token).

Use it when: You’re building a web app that can keep secrets securely on the backend.

2. Authentication flow

Authentication = adds identity layer

OIDC is built on OAuth 2.0, but it adds identity on top. The authentication flow is where OIDC connect really shines—it verifies who the user is and returns an ID token along with other OIDC tokens.

Use it when: You care not just about access, but about confirming identity as well. This flow is part of the OIDC specification itself.

3. Implicit flow

Implicit = legacy and risky

This flow sends OIDC tokens directly to the browser without exchanging codes.

Use it when: You’re building a public, JavaScript-heavy app that can’t store secrets.

Heads-up: It’s now discouraged because of security risks. Modern apps should use Authorization Code with PKCE instead.

4. Hybrid flow

Hybrid = flexible but complex

Want both speed and strong control? The hybrid flow gives you tokens and an auth code in one shot.

Use it when: You need more flexibility, like logging in on the web and using the session in a mobile app.

How does OIDC work?

Here’s the short version: OpenID Connect (OIDC) lets your app trust another system, an OIDC identity provider (OIDC IdP) to handle logins and confirm who users are. No passwords are stored in your app. But let’s walk through what actually happens in the back end.

Step-by-step: The OIDC flow in action

Let’s say a user wants to log in to your internal dashboard. Here’s what happens behind the scenes:

1. User clicks “Login.” The app (aka the relying party) sends them to an OIDC IdP, like Azure AD or Okta.
2. OIDC IdP handles authentication. The user logs in, can be with a password, or using biometrics, MFA, or even passkeys. The OIDC authorization flow kicks in here.
3. IdP sends an authorization code back to the app. This is a temporary code that proves the user has authenticated successfully.
4. App exchanges the code for tokens. The app calls the IdP’s token endpoint to get:
   • An ID token (who the user is)
   • An access token (what they can access)
   • (Optional) A refresh token (to keep the session alive without re-login)
5. Tokens get validated. The app checks the signature of each OIDC token to make sure it’s legit. It may also verify nonce, scope, and expiration time.
6. User gets access. The app now trusts the identity provided and gives the user access to the right resources.

Why is it important to SecOps and IT Admins?

• No more password sprawl. Users don’t create new passwords for every app. Instead, you centralize logins through an IAM OIDC provider.
• Endpoint visibility improves. You can track who accessed what, from where, and when, because every login request flows through the IdP.
• Sessions are token-based. If a token is stolen, you can revoke it. If the session looks risky, you can kill it. Tokens expire fast, reducing exposure.
• Admins control the config. With the right OIDC configuration, you decide what data comes in the ID token, how long tokens last, and what scopes apps can request.
• Built-in MFA and conditional access. Your OIDC IdP can layer on more security based on device, location, or risk signals without changing the app code.

OIDC is built for scale

Whether you’re managing hundreds of endpoints, OIDC Connect scales cleanly. You can:

• Add new apps without redoing login logic
• Set consistent policies from one dashboard
• Control identities across hybrid or multi-cloud environments

OIDC examples

1. Enterprise app SSO with Azure AD
A retail giant uses Azure AD as the OIDC identity provider (OIDC IdP). They are looking to enable secure single sign-on (SSO) for internal tools, HR systems, dashboards, dev platforms.

How it works:

• Azure AD handles the login via OIDC authorization.
• After authentication, the app receives an ID token and an access token.
• Admins can control access levels using OIDC configuration (groups, scopes, roles).

Why it works: No password storage. Centralized identity. Easy session tracking.

2. Mobile app login with Google OIDC
A mobile app needs a secure login with an identity tied to Google accounts.

How it works:

• The app uses the authorization code flow with PKCE.
• Google, acting as the IAM OIDC provider, authenticates the user.
• The app receives an OIDC token set with user info.

Why it works: Built-in 2FA. Strong identity. No need for your app to handle sensitive login data.

3. Hybrid environment with Scalefusion OneIdP and on-prem apps
You’re managing a hybrid setup, cloud apps like M365 or Salesforce, plus on-prem tools your teams still rely on. You want a unified login and stronger access control across both.

How it works:

• Scalefusion OneIdP acts as your central OIDC identity provider (OIDC IdP).
• You connect both cloud and on-prem apps using OIDC connect.
• For older apps, you use SAML bridging or custom connectors.
• OIDC configuration defines which users get access to what, and under which conditions.

Why it works: You get modern identity management without tearing down your legacy stack. One login across systems, centralized control, and detailed visibility into user sessions.

4. Third-party vendor access
A logistics partner needs access to a reporting portal, but you don’t want to manage their credentials.

How it works:

• You set up federated identity using OIDC connect with their IdP.
• You receive verified OIDC tokens from their provider.
• Access is scoped and temporary using OIDC configuration rules.

Why it works: No shared passwords. Full audit trail. Easy revocation.
These real-world examples show how OIDC specification adapts to different environments while giving you tight control, better security, and smoother logins.

OIDC vs other protocols

OIDC didn’t show up in a vacuum. It was built to fix real issues with older identity protocols. Here’s how it stacks up against the two most common alternatives: SAML and OAuth 2.0.

OIDC vs SAML

SAML (Security Assertion Markup Language) is XML-based and built mainly for web-based SSO. It’s been around for a while, especially in large enterprise environments, but it’s showing its age.

OIDC vs SAML: Key differences explained

• Format: OIDC uses lightweight JSON. SAML uses bulky XML.
• Integration: OIDC is easier and faster to implement across modern stacks.
• Mobile support: OIDC works well with mobile apps and APIs; SAML doesn’t.
• Token model: OIDC uses flexible ID, access, and refresh tokens. SAML uses signed assertions, which are harder to manage.
• Security: OIDC supports nonce, PKCE, and built-in token expiration. SAML often relies on custom logic to match that.
• Security advantage: The OIDC specification includes more modern, baked-in security controls. That means fewer manual fixes and fewer weak points for attackers to exploit.

OIDC vs OAuth 2.0

This one confuses a lot of teams. But here’s the key:

• OAuth 2.0 handles authorization (who can access what).
• OIDC Connect adds authentication (who is the user).

You don’t have to choose. OIDC is built on OAuth 2.0, which adds a layer to get identity data using ID tokens.

Why it matters to IT: OAuth alone can’t tell you who the user is. It’s great for third-party API access. But if you want user info (name, email, session), you need OIDC tokens.

Verdict: If you’re still relying on SAML or LDAP alone, you’re leaving flexibility and security on the table. OIDC configuration lets you work smarter, adapt faster, and scale without friction.

Benefits of OIDC

OpenID Connect (OIDC) is built for the way modern IT teams actually work. Whether you’re trying to reduce risk, manage access more efficiently, or scale securely, OIDC configuration gives you the flexibility to do it right. It helps you secure access, control sessions, and reduce complexity, without slowing anyone down.

Here’s what you actually gain by moving to OIDC connect:

1. Reduces risk of stolen passwords: With OIDC authorization, users authenticate through a trusted OIDC identity provider (OIDC IdP). That means no password storage inside your apps, no reuse across systems, and less exposure during breaches.

2. Standardized authentication: OIDC specification is based on OAuth 2.0, using proven standards like HTTPS and JSON. It replaces messy, inconsistent auth logic with one clean model across your environment.

3. Streamlines identity management: When you centralize identity with an IAM OIDC provider, you reduce the overhead of managing multiple credentials, roles, and login paths. It simplifies onboarding, deactivation, and compliance audits.

4. Enhances security controls: You control what goes into each OIDC token, how long sessions last, and which scopes apps can request. Features like PKCE, nonce, and token validation give you tools to prevent token theft and replay attacks.

5. Seamless user experience: Users log in once and get access to what they need, across devices, apps, and networks. No confusing redirects. No extra passwords. Just one secure, fast flow built into your OIDC configuration.

Pre-requisites before adopting OIDC

Rolling out OpenID Connect (OIDC) isn’t just about flipping a switch. A smart implementation means thinking about security, scale, and how your apps interact with the OIDC identity provider (OIDC IdP). But before you roll out OpenID Connect (OIDC), it’s smart to assess your environment.

A solid plan can help you avoid blind spots and make the most of your OIDC configuration. Here’s what to check before going live with an IAM OIDC provider:

a. Security readiness

• Token Handling: Can your systems properly store, validate, and expire OIDC tokens?
• TLS Everywhere: All OIDC flows depend on secure HTTPS.
• Session Management: You’ll need a way to detect and revoke risky sessions.

b. Integration capabilities

• Can your apps handle redirects, scopes, and token parsing?
• Are your dev teams comfortable working with JSON, OAuth 2.0, and ID token structures?
• Does your current stack support modern OIDC Connect flows or will you need workarounds?

c. Provider dependency

• Are you picking a vendor with strong support and uptime SLAs?
• Does your OIDC IdP offer easy API access, audit logs, and configuration flexibility?
• Can it handle hybrid environments and legacy systems.

10 best practices for OIDC implementation

1. Use authorization code flow with PKCE: Always choose the authorization code flow with PKCE for public clients. It protects against code injection and intercept attacks, especially on mobile and browser-based apps.

2. Validate all OIDC tokens: Don’t assume a token is safe. Always validate:

• Signature
• Issuer
• Audience
• Expiration time 

This ensures the OIDC token hasn’t been tampered with or forged.

3. Rotate client secrets regularly: Treat secrets like credentials. Rotate them on a schedule, use unique secrets per client, and store them securely.

4. Set tight token expiration times: Short-lived tokens reduce the damage if one gets exposed. Use refresh tokens with strict reuse policies when sessions need to last longer.

5. Define scope strictly: Control what each app can access. Use narrow scopes in your OIDC configuration, only what’s required, nothing more.

6. Implement nonce checks: Nonce values prevent replay attacks in the OIDC authorization flow. Always check the nonce returned in the ID token against what was sent in the request.

7. Limit redirect URIs: Lock down redirect URIs to only what’s needed. Don’t allow wildcards. This helps stop malicious redirects and token interception.

8. Monitor and audit every login: Use logs from your IAM OIDC provider to track sign-ins, token grants, and scope usage. Flag anomalies in location, device, or frequency.

9. Plan for key rotation: Use JWKS (JSON Web Key Sets) and automated key rotation to manage the public keys used to validate tokens. Don’t rely on static keys.

10. Test and re-test OIDC flows: Run threat modeling and test how each OIDC Connect flow performs under pressure. Check what happens when tokens expire, are reused, or misconfigured.

Tip for IT Admins: Most of these features come built-in with providers like Scalefusion OneIdP, but you still need to configure and monitor them properly.

Scalefusion OneIdP for implementing OIDC authentication

Scalefusion OneIdP brings the power of OIDC Connect to a platform built for modern IT and SecOps teams. It supports standard OIDC authorization flows, enabling seamless integration with both new and legacy systems. 

Designed for compatibility, OneIdP helps organizations replace fragmented login methods with a unified identity layer that scales securely across apps, platforms, and devices. OneIdP can act as both an OIDC identity provider (OIDC IdP) and an IAM OIDC provider, supporting features like:

• Authorization Code Flow with PKCE
• Issuance and management of OIDC tokens (ID, access, refresh)
• Microsoft external authentication method integration
• Shared signal support for federated Apple logins

Contextual OIDC isn’t a future state. With Scalefusion OneIdP, it’s how secure access happens by validating device trust and compliance in real time.

FAQs

1. Is OIDC secure?

Yes. The OIDC specification builds on OAuth 2.0 and adds a secure OIDC identity layer. It supports strong encryption, token validation, and protection against common threats like token replay. When implemented correctly, OIDC token handling ensures secure authentication across web, mobile, and cloud platforms.

2. Why should developers use OIDC?

OpenID Connect (OIDC) simplifies identity integration. With just a few endpoints and a standardized OIDC configuration, developers get authentication, single sign-on, and user info from a trusted OIDC identity provider (OIDC IdP). It works across apps and devices, supports federation, and scales easily for modern IAM use cases.

3. How is OpenID Connect different from OpenID 2.0?

OIDC is a modern protocol built on OAuth 2.0, unlike OpenID 2.0, which predates it and lacks token-based authorization. OIDC introduces the ID token, standardized user claims, and support for REST/JSON. It’s easier to implement and far more secure, making it the preferred IAM OIDC provider choice.

4. How does OpenID Connect relate to the FIDO Alliance?

In essence, OIDC and FIDO complement each other. OIDC Connect handles federated identity and session authorization, while FIDO focuses on passwordless, phishing-resistant login. Combined, they strengthen authentication: FIDO ensures the login is secure; OIDC authorization shares the identity data with relying apps securely.

5. Is OIDC more secure than SAML?

Yes, in most modern use cases. OIDC uses short-lived OIDC tokens, supports better mobile compatibility, and avoids XML-based parsing risks seen in SAML. It’s API-friendly and aligns with today’s app architecture, making OIDC configuration less error-prone and more secure.

6. Why use OIDC instead of SAML or LDAP?

OIDC is built for the cloud, APIs, and mobile. Unlike SAML, it uses JSON and REST. Unlike LDAP, it’s designed for federated identity and doesn’t require direct directory access. With a trusted OIDC IdP, you get modern, decentralized identity handling that scales across apps.