OAuth Token Expiry: How to Check if a Token Is Expired

Handling OAuth token expiry is a complex process involving various signals and mechanisms to ensure reliable token management and prevent common bugs in production environments. OAuth access tokens can be in the form of JWTs, which are self-contained and can be validated client-side, or opaque tokens, which require server-side validation. Key indicators of token expiry include the computed local expires_at timestamp, the exp claim in JWTs, and 401 API responses, with the latter being the only authoritative signal. Effective token management involves strategies like proactive token refresh before expiry, implementing single-flight refresh patterns to prevent concurrent refresh attempts, and understanding whether refresh tokens are static or rotating. Unified.to centralizes OAuth handling across multiple integrations by providing a unified infrastructure that includes proactive refresh, single-flight protection, automatic rotation handling, and consistent error semantics, ensuring seamless integration across various OAuth 2.0 variants.