14.14 Observability & Operations

1. What It Is in Plain Words

Observability provides visibility into the internal state of a software system based on its external outputs: metrics, logs, and distributed traces.

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2. How This Project Uses It

In backend/src/observability/ and security/audit.py:

• Metrics: Prometheus exports for ingestion rate, rating latency percentiles, and ledger balance discrepancies.
• Structured Logs: JSON-formatted logs containing correlation IDs for end-to-end request tracing.

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3. 30-Second Interview Answer

"Observability is centered around Prometheus metrics and structured audit logs. We track four key golden signals: ingestion request rate, p95 rating latency, error rate, and a dedicated ledger balance gauge that triggers an immediate P0 alarm if any transaction fails debit-credit conservation."