What are the advantages of using JWTs?

Imagine we are building a simple mobile app where users log in, and we want to avoid querying our database on every single API request just to verify who they are. How would you use a JWT to solve this, and what specific information would you store inside the token itself?

Suppose a user logs out of our frontend application, but their JWT hasn't expired yet. If an attacker manages to steal that token right after the logout, can they still access our APIs? How would you handle this scenario to keep the user's account safe?

We recently migrated our web app from session cookies to JWTs. Now, users are complaining that when an admin updates their roles or permissions, they still have their old permissions until they log out and log back in. Why is this happening, and how would you fix it without completely losing the benefits of JWTs?

Our security team flagged that we are storing sensitive user data like internal database IDs and department names inside our JWT payload, which is sent to the client. Is this actually a security risk if the JWT is cryptographically signed? How would you address their concern?

We are designing a high-throughput microservices architecture with over 50 downstream services. If we use stateless JWTs to avoid a centralized session store bottleneck, how do we handle instant token revocation—like when a user's account is suspended—without re-introducing a single point of failure or a heavy database lookup on every request?

We want to implement a 'remember me' feature for our mobile app using access and refresh tokens. How would you design the token lifecycle, storage on the device, and rotation strategy to minimize the window of vulnerability if an access token is compromised?

Our enterprise platform is migrating from a legacy monolithic session-based architecture to a federated, multi-tenant microservices mesh. Some teams want to use JWTs for end-to-end propagation, while others argue for reference tokens at the API gateway level. How would you evaluate these two approaches, and what architecture would you propose to balance security, latency, and cross-team autonomy?

As we scale our B2B SaaS platform, we need to support both our own first-party UI and third-party developer integrations. How would you architect an identity and token issuance strategy that leverages JWTs for our UI but handles API keys or OAuth tokens for external developers, ensuring we don't end up maintaining two completely separate auth pipelines?