Alchemy Reference Architecture System Architecture Project Structure Key Design Decisions | Decision | Choice | Rationale | |----------|--------|-----------| | SDK | | Official, typed, Enhanced + NFT APIs included | | Multi-chain | Client factory pattern | Lazy initialization, shared API key | | Caching | In-memory with TTL tiers | Block data = 12s, metadata = 24h | | Rate limiting | Bottleneck with CU weights | Matches Alchemy CU budget model | | Frontend access | API proxy | Never expose API key to browser | | Real-time | WebSocket subscriptions | Lower cost than polling | | Testing | Hardh…