Senior .NET Backend Engineer

FlashAlpha is a production options analytics platform. Live OPRA and CME
market data feeds come in, analytics come out - gamma exposure, dealer
positioning, option flow, volatility surfaces, historical replay - served
through a public API to systematic traders, funds and quant desks.

The stack is .NET throughout, running in Docker on bare metal, with SQL
Server and QuestDB behind it. There is a lot of it, it runs during market
hours, and it needs someone whose job is to keep it healthy and keep it
growing.

You would be the second pair of hands on the whole system. This is a
broad role, not a narrow one.

WHAT YOU WILL DO

- Monitoring and observability. Build the dashboards, log sinks and
alerting that make the system's failure modes visible.
- Production debugging. Diagnose and fix issues across ingest, API and
data layers.
- QuestDB and data quality. Reconciliation checks, scheduled jobs,
backfills, verifying that what we serve matches what we ingested.
- Feature development. New API endpoints and parameters, new analytics,
extending existing ones.

REQUIREMENTS

- 3+ years commercial C# / .NET, backend focused.
- Linux and Docker. You can read a container log and a systemd unit
without help.
- SQL. Comfortable writing and reading non trivial queries.
- You use AI coding tools daily and have opinions about where they help
and where they confidently lie to you.
- Working knowledge of equity markets. You know what a ticker, a trading
session, a corporate action and a settlement price are.
- English or Polish, written and spoken.
- Self directed. Comfortable owning a problem end to end without a
detailed spec.

NICE TO HAVE

- Options knowledge: greeks, implied volatility, open interest, expiry
mechanics, market maker hedging.
- A columnar or time series database: QuestDB, ClickHouse, TimescaleDB,
kdb+, InfluxDB.
- Market data vendors: OPRA, CME, Databento, Polygon, ThetaData.
- Observability tooling: Grafana, Prometheus, OpenTelemetry, Seq.
- Python for data and analysis work.

WHAT WE OFFER

- Fully remote. Flexible hours, with overlap on US market hours where
the work requires it.
- B2B contract, 18 000 - 20 000 PLN/month depending on experience.
- Long term - 1 year plus, with a roadmap that is already full.
- Direct ownership. No layers, no committees, no ceremony. You ship.
- A domain worth learning. Options market structure is genuinely
interesting and the knowledge compounds.