Copy-ready bullets for a systems / MLSys / infra SWE resume. All metrics are infrastructure facts (latency, cost, throughput, fault-tolerance) — no profit or return claims.
One-liner (project header):
Real-time market-data ingestion + offline strategy-evaluation system — async WebSocket ingestion, a ~$0/month self-healing deployment, and a paper-evaluation harness that reaches a validate-before-you-build verdict. Python. [github.com/…/realtime-md-eval]
Bullets (pick 4–6):
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Built a real-time order-book ingestion service (async WebSocket, in-memory snapshot
- delta reconstruction, watchdog reconnect) delivering ~90 ms update latency — ~100× fresher than the 10 s REST-polling baseline.
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Ran it 7×24 at ~$0/month on a GCP free-tier
e2-micro: IPv6-only networking to avoid the external-IPv4 charge, IAP-tunneled SSH (no public port), and systemdRestart=alwaysself-healing with daily sessions that prune resolved markets and resume automatically across crashes and reboots. -
Cut each polling round to a single batched
POST /booksrequest, keeping egress under the 1 GB/month free-tier cap while tracking multiple live markets. -
Designed an offline strategy-evaluation harness that paper-simulates fills (modeling adverse selection), persists multi-day state, and attributes PnL by price-volatility regime, emitting a deterministic go/no-go verdict via a single pure aggregation function.
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Used the evaluation to make a validate-before-deploy call: measured that the candidate strategy is net-negative under news-driven volatility (adverse selection) and net-positive in calm, low-competition conditions — capturing a live geopolitical news spike as the decisive case study — before committing to a low-latency executor.
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Refactored a research prototype into a tested, importable Python package (I/O split from pure logic, single-source fee model + categorization, pure report aggregation) with a
pytestsuite covering the book state machine, quoting/inventory math, fee curve, depth-walk, and verdict logic.
Tech: Python, asyncio, websockets, systemd, GCP (free-tier e2-micro, IAP), pytest.