Why understanding OpenID and its alternatives matters
When you sign into an app, two things are happening behind the scenes: proving who you are (authentication) and getting permission to access things (authorization). The technologies and protocols that handle authentication affect user experience, security, and how easy it is to integrate with other systems. OpenID and the other common options each approach identity differently, so picking the right one depends on the use case: consumer single sign-on, enterprise integrations, mobile apps, or passwordless flows. This article walks through the main options in plain language and explains when to choose each one.
What is OpenID and what changed with OpenID Connect?
“OpenID” originally referred to an older, decentralized system for letting people log in to many websites using a single identity provider. It was popular in the early web but has mostly been superseded for modern applications. OpenID Connect (often abbreviated OIDC) is the contemporary specification built on top of OAuth 2.0. OIDC adds a standardized way to perform authentication and return identity information (called ID tokens), while OAuth by itself is designed for authorization, not authentication.
In short: classic OpenID is mostly historical, OpenID Connect is the modern, widely supported choice for federated authentication, and it works well for web and mobile apps because it uses json, REST-style endpoints, and modern token formats like JWT.
Key alternatives at a glance
Several alternatives to OpenID / OIDC are commonly used. Each has strengths and constraints depending on whether you prioritize enterprise features, simplicity, or strong phishing-resistant login methods.
- OAuth 2.0: Primarily an authorization framework that lets applications obtain limited access to user resources. It is not an authentication protocol on its own, though it’s the foundation OIDC builds on.
- SAML (Security Assertion Markup Language): An older XML-based standard widely used by enterprises for single sign-on (SSO) between identity providers and service providers. It is highly mature and fits well with corporate identity systems.
- WebAuthn / FIDO2 (passwordless): A set of browser APIs and server flows for strong, phishing-resistant authentication using security keys or platform authenticators. Best for high-security or passwordless-first experiences.
- LDAP / Active Directory: Directory protocols for managing user accounts within organizations. They are often used for internal authentication systems rather than public web SSO.
- Social logins and proprietary identity providers: Google, Facebook, Apple Sign In, and similar services offer OAuth/OIDC-based logins that simplify onboarding for consumer apps.
OpenID Connect vs OAuth 2.0 vs SAML , how they differ for beginners
A common source of confusion is the relationship between OAuth and OpenID Connect. OAuth 2.0 handles delegated authorization: it lets a user grant a third-party app permission to act on their behalf, typically by issuing access tokens. OpenID Connect is an identity layer on top of OAuth 2.0 that standardizes how to authenticate a user and receive verified identity information through an ID token. SAML, by contrast, predates both and uses XML messages for authentication assertions,SAML is frequently used for enterprise SSO where compatibility with corporate identity providers is important.
If you need simple, modern authentication for web and mobile applications, OIDC is usually the practical choice. If you’re integrating with legacy enterprise systems or services that only speak SAML, you will use SAML. If your goal is secure, passwordless sign-in for high-risk contexts, consider WebAuthn in addition to or instead of OIDC.
Security and user experience trade-offs
Security is shaped by protocol design and implementation choices. OIDC benefits from token-based flows, JSON Web Tokens (JWT), and support for refresh tokens and short-lived access tokens, but these must be implemented carefully to avoid token leakage, improper storage, or client-side attacks. SAML is robust and well-understood in enterprise settings, but its XML format and browser redirects can be more complex to debug. WebAuthn raises the bar on phishing resistance because credentials are bound to the site origin and cryptographic keys are stored on the device; however, it requires device support and may be harder to adopt for broad consumer bases.
Which should you pick? Practical recommendations
For most modern public-facing web and mobile apps, OpenID Connect is the best starting point. It provides standardized identity tokens, works across platforms, and has strong support in identity providers and frameworks. Use OIDC together with secure practices: use https everywhere, validate ID tokens, rely on short-lived tokens, and protect refresh tokens.
Choose SAML when you need to integrate with enterprise identity providers (like many corporate Single Sign-On systems) or when your customers require SAML assertions. Consider WebAuthn if you want to offer or mandate passwordless, device-bound authentication for improved security. OAuth 2.0 is appropriate when you only need authorization capabilities,granting apps access to APIs,while delegating authentication to OIDC or another proven method.
Quick decision checklist
- If you want standardized, modern authentication for web/mobile, pick OpenID Connect.
- If you must integrate with corporate SSO or older systems, use SAML.
- If you aim for passwordless, phishing-resistant login, evaluate WebAuthn/FIDO2.
- If you only need to authorize access to APIs, use OAuth 2.0 (and add OIDC for identity).
- If you need fast onboarding with social profiles, use OIDC/OAuth providers like Google or Apple Sign In.
Implementation tips for beginners
Start with a library or SDK that matches your platform rather than trying to implement protocol details from scratch. Popular frameworks and identity providers handle token exchange, cryptographic checks, and session management so you can focus on integrating the user experience. Pay attention to common pitfalls: validate tokens against the provider’s public keys, check token expiration and intended audience, use secure storage for refresh tokens, and implement logout and session revocation where appropriate.
Testing is essential: use test accounts, inspect tokens in development, and validate error handling. If you support enterprise customers, expect additional requirements like attribute mappings, signed assertions, or custom SAML configurations,budget time for that complexity.
Costs and ecosystem considerations
Beyond technical fit, think about ecosystem and cost. Many identity providers offer managed OIDC/SAML services with built-in features such as social logins, multi-factor authentication, analytics, and compliance certifications. Those services speed time to market but can add monthly costs. Self-hosting identity solutions offers control and potentially lower recurring costs but increases maintenance burden and security responsibility. Choose what balances your team’s capabilities and your users’ security needs.
Concise summary
OpenID in its original form is largely historical; OpenID Connect is the modern identity layer built on OAuth 2.0 and is the recommended choice for most web and mobile authentication needs. SAML remains important for enterprise SSO, WebAuthn is the go-to option for strong passwordless authentication, and OAuth by itself focuses on authorization rather than authentication. Pick technology based on use case, integration requirements, and security goals, and rely on well-maintained libraries and identity providers to avoid common implementation pitfalls.
FAQs
Is OpenID Connect the same as OAuth 2.0?
No. OAuth 2.0 is an authorization framework that lets apps request access to resources. OpenID Connect is an identity layer built on top of OAuth 2.0 that standardizes authentication and provides ID tokens with user information. Use OIDC when you need to authenticate users and OAuth when you need delegated access to APIs.
When should I choose SAML instead of OpenID Connect?
Choose SAML when you need to integrate with enterprise identity providers that require SAML, or when your customers expect SAML-based SSO. SAML is common in corporate environments and often required for integrations with legacy systems and enterprise identity management solutions.
Can I use WebAuthn with OpenID Connect?
Yes. WebAuthn handles how a user authenticates (e.g., with a security key or platform authenticator). You can integrate WebAuthn into an OIDC-based flow so the user authenticates via WebAuthn and the identity provider issues an ID token under OIDC. This combines strong phishing-resistant login with the interoperability of OIDC.
Are social logins secure enough for production?
Social logins provided by major identity platforms (Google, Apple, etc.) are generally secure and convenient for consumer apps, but evaluate privacy and data requirements. For sensitive or regulated applications, you may need additional verification or enterprise-grade identity management beyond social login.
What are the first steps to add OpenID Connect to my app?
Choose a trusted identity provider or library, register your application with the provider, implement the recommended OIDC flow (authorization code flow with PKCE for public clients), and validate tokens according to the spec. Use HTTPS, secure token storage, and test thoroughly in development before going live.
