Figma built an in-house Redis proxy called FigCache to replace a fragmented caching stack that was threatening site availability. Written in Go and built on a custom RESP-based RPC framework called ResPC, FigCache sits between application services and AWS ElastiCache clusters, handling connection pooling, command routing, and cross-slot fanout transparently. Configuration is expressed as Starlark programs evaluated at runtime, enabling routing logic changes without binary redeployments. The system supports Redis Cluster emulation for legacy clients, provides unified observability, and has achieved six nines of uptime since its 2025 production launch. Migration was designed to be reversible at every stage using feature flags, and the architecture is backend-agnostic, supporting potential future swap-outs to AWS MemoryDB or Postgres.
Sort: