Overview

The platform is a Solana-based real-time memecoin trading system, designed for high throughput, low latency, fault tolerance, and consistent order matching and event streaming. The production environment uses a mix of self-hosted Solana nodes and third-party RPC providers (e.g., QuickNode, Triton, Alchemy), and your system must dynamically balance load across them to maintain a P95 latency target of under 100 ms (for interview purposes).

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Problem Statement

Design and explain:

1. Cloud Architecture – multi-region deployment, network, security layers.
2. Solana RPC Node Architecture – self-hosted nodes, third-party providers, cache/proxy layer, and latency balancing.
3. Indexer Design – collecting and indexing transaction logs and program events.
4. Trading Engine Cluster – order matching, order book synchronization, horizontal scaling.
5. Event Streaming Pipeline – real-time event delivery (Kafka/Kinesis/Redis Streams-like).
6. Hybrid Node Load Balancing Strategy – latency-aware, health-based, and cost-aware routing.
7. Monitoring, Orchestration, and Auto-Recovery Strategy.

Constraints

• Target latency: P95 ≤ 100 ms
• Order matching must guarantee ordering and atomicity
• Indexer may be eventually consistent
• Event delivery: at-least-once with idempotent consumers
• System should be fault tolerant and cost-efficient.

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Evaluation Criteria

• Performance – throughput and latency targets
• Availability/Fault Tolerance – auto-failover, health checks
• Consistency/Accuracy – order atomicity, duplication handling
• Scalability – horizontal expansion strategy
• Observability – metrics, tracing, and logs
• Security – RPC auth, data integrity, signature verification
• Cost Optimization – balancing self-hosted vs third-party RPC usage

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Deliverables

During the interview, you should:

1. Explain your system architecture verbally (you can sketch it out).
2. Describe component interaction and data flow clearly.
3. Walk through failure scenarios and recovery processes.
4. Propose event schema/message formats for the indexer and pipeline.
5. Use the provided solution.py to demonstrate component simulation (no actual Solana calls needed).

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Tips

• Reduce RPC bottlenecks using caching, batching, and latency-based routing.
• Indexer should listen to Solana program logs, transform them into CDC-style streams.
• The trading engine must maintain atomic order matching and idempotency.
• Partition engines by trading pairs; coordinate cross-shard trades via a leader or coordinator.