Backend & APIs · Intermediate
Build Your Own Redis
Build an in-memory key-value server that speaks the Redis RESP protocol over TCP and serves GET, SET, and key expiry to many concurrent clients.
You build a Redis-compatible server that listens on a TCP socket, parses the RESP wire protocol, and responds to commands like PING, SET, GET, DEL, and EXPIRE from an in-memory data store. You implement the protocol framing yourself, manage a shared key-value map, and handle many clients concurrently using an event loop or a thread-per-connection model. Because it is wire-compatible, you can test it with the real redis-cli. It is worth building because it forces you to confront network programming, binary-safe protocol parsing, concurrency, and time-based key expiration, the core concerns of any high-throughput backend service. It is resume-worthy because it shows you can implement a well-known protocol from its specification and reason about concurrent access to shared state.
What you build
- Listens on a TCP socket and accepts many simultaneous clients
- Parses and serializes the RESP protocol including arrays and bulk strings
- Implements PING, ECHO, SET, GET, and DEL commands
- Supports key expiry with EXPIRE, TTL, and SET ... PX options
- Handles concurrent access to the shared store safely
- Lazily evicts expired keys on access and via background sweeps
- Interoperates with the official redis-cli client
What it teaches
- TCP socket server programming
- Implementing a binary-safe wire protocol from a spec
- Concurrency and safe shared-state access
- Time-based key expiration strategies
- Command dispatch and request/response loops
- Testing against a real client and benchmark tool
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Take it further
- Add list or hash data types with their command families.
- Implement persistence via an append-only file you can replay on startup.
- Add pub/sub channels with SUBSCRIBE and PUBLISH.
