Table of Contents
Question 1: Ownership and Borrowing
Question 2: Lifetimes
Ask: 'Write a function that takes two string slices and returns the longer one.' Look for explicit lifetime annotations `<'a>` and understanding that the return value must have the same lifetime as the inputs.
Question 3: Error Handling
Ask: 'You're reading a file that may not exist. How do you handle this?' Strong candidates use `Result` with `match` or `?` operator, not `.unwrap()`.
Question 4: Concurrency
Ask: 'How would you share data across multiple threads?' Look for `Arc<Mutex<T>>` for shared ownership, or `channel` for message-passing.
Question 5: Async Rust
Ask: 'When would you use async vs sync Rust?' Senior candidates discuss Tokio runtime, .await, and trade-offs for concurrent connections vs CPU-bound work.
What Strong Rust Answers Actually Look Like
Signs you're speaking with an experienced Rust engineer:
- ✦ Explains ownership using practical examples rather than textbook definitions
- ✦ Discusses trade-offs between cloning and borrowing
- ✦ Understands when lifetimes can be elided versus explicitly annotated
- ✦ Mentions error propagation strategies instead of relying on unwrap()
- ✦ Can compare message passing versus shared state concurrency
- ✦ Discusses async overhead and when synchronous code is preferable
Common Rust Interview Mistakes
Mistakes that often lead to poor hiring decisions:
- ✦ Focusing exclusively on syntax trivia
- ✦ Ignoring debugging and troubleshooting ability
- ✦ Assuming C++ experience automatically translates to Rust expertise
- ✦ Testing only ownership without evaluating concurrency knowledge
- ✦ Using generic algorithm interviews instead of systems-focused scenarios
- ✦ Skipping practical coding exercises
How Senior Rust Engineers Stand Out
Senior Rust engineers typically move beyond language mechanics and discuss architecture decisions, memory behavior, observability, deployment concerns, performance bottlenecks, and operational trade-offs. The strongest candidates explain why a solution should be chosen rather than simply demonstrating that it works.
Beyond the Questions
These questions test fundamentals. For senior roles, add a take-home project. Offline Pixel pre-vets all Rust engineers so you don't need to design these interviews yourself.
Continue reading
Need more interview questions?
Get our complete Rust interview guide with 30+ questions and evaluation rubric.
Download Guide