What I've shipped.

Streaming RAG ingestion pipeline with Kafka backpressure, batched embeddings, provider fallback, idempotent pgvector upserts, DLQ retries, and p95 freshness under 10 seconds.

Open-source CI framework for RAG regression with golden sets, LLM-as-judge scoring, GitHub Actions merge gates, Prometheus drift tracking, and sub-5-second p95 eval runs.

A 4-agent retrieval-augmented system on LangGraph with RAGAS evaluation. Faithfulness 73% → 91% over a single-chain baseline.

Fault-tolerant task scheduler built from scratch — 3-node Raft quorum, exactly-once execution under node crashes, lease-based worker locking, and Kubernetes HPA auto-scaling on queue depth.

A federated social network built from first principles — multi-node Go backend, Raft consensus for leader election, CRDTs for feed merging, and a timeline fan-out system that stays consistent under network partitions.