Senior Backend Engineer, Systems & Caching

We run a high-traffic API gateway, and a small in-memory cache sits on its hottest path. To avoid the overhead of background threads, the team keeps that cache hand-written and dependency-free. We're looking for a senior backend engineer who enjoys this kind of systems work to own it: a generic store with size limits, expiry, an eviction policy, and accurate stats.

What you'll do:

• Make lookups and recency tracking O(1), replacing today's linear scan with a proper index or slab-backed list
• Implement time-based expiry cleanly, keeping an entry that expired distinct from one evicted to make room
• Choose the right entry to drop under LRU or LFU while keeping every internal structure consistent
• Keep the hit, miss, and expiration counts exact

What we're looking for:

• Strong Rust and a real feel for ownership and borrowing
• Comfort with the data structures behind a cache, like intrusive lists, slabs, and index maps
• A systems mindset that values correctness and reaches for unsafe only with a good reason

Nice to have:

Experience injecting a clock to keep time-based code testable, and comfortable with generics and trait bounds