Observability

Governed by STD01-11 (Observability, audit and evidence): the right record for the right purpose — application telemetry, payment history, and analytical reporting are separate concerns, not one system doing all three.

Record type	Purpose
Structured logs	Technical diagnostics; searchable, short/medium retention, no unnecessary sensitive payloads.
Metrics	Rates, latency, capacity, health, errors, circuit state, backlog, SLO measurement.
Distributed trace	Request/task path and timing across process boundaries.
PH-09 Journal	Immutable material payment/business timeline — not a replacement for logs.
Warehouse / reporting	Historical analytics and trends — not authoritative for live payment execution decisions.
Secure evidence store	Raw or restricted external payload/file evidence referenced by domain/journal records.

This is the technical telemetry layer underneath both PH-09 (the immutable payment record) and PH-13 (Payment Operations and Reporting, the product-facing search/dashboard surface) — neither of those replaces it, and it doesn't replace either of them.

Observability platform

Decision required — current lean: Datadog (open, ENG-01 §4 / Decision Register), per Build vs. Buy. Not yet built.

Minimum external-dependency metrics (STD01-11)

Request/operation volume, success/rejection/error/timeout counts, latency distribution, circuit-state transitions and time spent open/degraded, admission rejects and queue/backlog depth, technical retry volume and exhaustion, OUTCOME_UNKNOWN count and time to resolution, and last successful interaction / health freshness for operationally important Connections. Not yet built.