Dashboard
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Build a Key-Value Store
Storage & Caching · dict-backed store with TTL and HTTP API · ~45 min
Real-World Systems
Storage & Caching
Build a cache that survives a crash, and the storage engine underneath it.
7 challenges · ~6 h
Probabilistic Structures
Answer membership, frequency and count-distinct questions over huge streams in kilobytes.
4 challenges · ~3 h
Indexes & Structures
Build the indexes behind autocomplete, ordered maps, range queries, geo search and tamper-proof data.
8 challenges · ~7 h
Networking & Protocols
Speak HTTP, DNS, SSE and WebSocket at the wire level, and make a lossy channel reliable.
6 challenges · ~6 h
Traffic & Resilience
Put a gateway in front of a fleet that throttles abuse, spreads load and survives failing backends.
7 challenges · ~7 h
Async & Messaging
Move work off the request path and deliver it at-least-once without doing it twice.
7 challenges · ~6 h
Partitioning & Replication
Spread data across nodes, keep the copies in sync, and merge concurrent edits without conflicts.
8 challenges · ~8 h
Coordination & Consensus
Make a cluster agree on a leader, a lock, or a transaction outcome even when nodes fail.
4 challenges · ~4 h
Data Pipelines
Turn a stream of events into batch jobs, streaming aggregates and read models.
4 challenges · ~4 h
Platform Engineering
Build the plumbing that lets services find, trust and observe each other.
4 challenges · ~3 h