What is the difference between context API and Redux?

0-2 years experience

1. 1You need to share a user's theme preference across a few components in a small app. Would you use Context API or Redux, and why?
2. 2If you add a new value to a Context provider but forget to wrap a component with the provider, what will happen at runtime?
3. 3How would you read a value from a Context inside a functional component without converting it to a class component?

2-5 years experience

1. 1You’re adding a shopping cart feature that many components will use and may need persistence. How do you decide between Context API and Redux, and what trade‑offs do you consider?
2. 2During a code review you notice a component re‑renders on every state change even though it only needs a small slice of the cart. What could be causing this if you’re using Context, and how would you fix it?
3. 3You introduced Redux to an existing app that already uses Context for authentication. After the change, some UI stops updating. What debugging steps would you take?

5-8 years experience

1. 1Our team is building a large dashboard with dozens of widgets that need to share global settings and also support time‑travel debugging. How would you architect state management, and why might you combine Context with Redux?
2. 2We observed performance degradation when using Context for a frequently updating data stream. What strategies can you employ to mitigate the impact, and when would you switch to Redux?
3. 3Explain how you would handle server‑side rendering of initial state when using Redux vs Context, and what pitfalls to watch for.

8+ years experience

1. 1The company plans to migrate a legacy monolith that heavily uses React Context for global state to a micro‑frontend architecture. What considerations would guide a decision to adopt Redux across teams, and how would you manage the transition?
2. 2Across multiple product lines, some teams prefer Context for feature flags while others use Redux for data fetching. How would you establish a consistent state‑management strategy that balances performance, developer experience, and long‑term maintainability?
3. 3If you had to design a shared state library that satisfies both the simplicity of Context and the advanced capabilities of Redux, what core abstractions would you define and why?