How to handle concurrency with OAuth token refreshes

OAuth 2.0 addresses security with short-lived access tokens but introduces challenges in managing token refreshes, notably concurrency issues. These issues occur when multiple processes simultaneously attempt to refresh tokens, leading to potential race conditions and API failures. To mitigate these problems, implementing locking mechanisms is crucial to ensure that no API requests use a token during its refresh and that only one refresh process runs per token. Solutions include using in-memory locks for single-instance applications and distributed locking with Redis for multi-instance environments. Additionally, caching tokens and retrying requests on 401 errors can optimize performance. Proper handling of token expiration and refresh failures, as well as considering third-party services like Nango for OAuth management, are recommended to maintain robust and reliable integrations.