PostHog OAuth refresh token invalid_grant — What it means & how to fix it

Integrating with PostHog using OAuth 2.0 often leads to issues with failed token refreshes, commonly indicated by the "invalid_grant" error, which disrupts data syncs, webhooks, or scheduled exports. This error arises when the refresh token is expired, revoked, or stale due to token rotation practices or concurrent refresh operations. To address this, it's crucial to ensure the use of the latest refresh token, verify the correctness of refresh requests, and manage token refresh as a shared resource among concurrent processes to avoid race conditions. Various scenarios such as user revocation, app uninstallation, and mismatched client credentials can also invalidate tokens, necessitating re-authorization. Implementing a strategy for regular token refreshes, monitoring for invalid_grant trends, and providing a smooth re-authentication user experience can mitigate these issues. Additionally, utilizing tools like Nango can automate and streamline the token management process, reducing the complexity of handling OAuth token lifecycle challenges.