Production Engineering for Trading
Szymon Kopyciński · 23 September 2026
Production engineering
Production
The live environment where a real system operates.
Because production trading systems trade real money, standards are much stricter than in research environments.
Dev / Development
An environment where software is actively developed and tested.
Staging
An environment that closely resembles production without being production.
Simulation
A controlled representation of a real system.
Trading simulations attempt to reproduce markets, exchange behaviour, fills, latency and counterparties.
Replay
Running previously recorded market data through a system again.
Replay is widely used for testing and debugging market-data and trading systems.
Deterministic
A system that produces the same output whenever it receives the same input under the same conditions.
Determinism makes systems easier to test and debug, and makes replay reliable.
Idempotent
An operation that has no additional effect when performed more than once after the first successful application.
Idempotency is important in distributed systems, where retries occur.
State
Information a system currently holds in memory or storage.
An order book, open orders and positions are all examples of state.
Stateless
A component that does not retain information between requests.
Stateless systems are easier to scale, but trading systems usually need substantial state.
Source of truth
The authoritative system or dataset whose state is considered correct.
Failover
Switching to a backup system after the primary system fails.
Redundancy
Maintaining multiple systems or components so that one failure does not stop the overall service.
High availability
Designing a system to remain operational despite failures.
Fault tolerance
The ability of a system to continue operating correctly when components fail.
Observability
The ability to understand what a system is doing from its outputs.
Common observability tools include metrics, logs, traces, dashboards and alerts.
Metric
A numerical measurement collected from a system.
Examples include order rate, CPU usage, message latency, fill rate and packet loss.
Log
A recorded description of events occurring within software.
Good logs are essential for reconstructing what happened during a trading incident.
Audit log
A durable record of important actions or events.
Trading systems maintain detailed audit trails for orders and executions.
Part of Glossary Index · Previous: Trading Systems & Market Connectivity · Next: Useful Abbreviations
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