Event bus для банка: nervous system операций

Зачем банку event-driven core

Banking operations — каскад events: transaction → fraud check → AML check → posting → notification → reconciliation → reporting. Без event bus каждое connection точка point-to-point integration.

К 5-летнему масштабу banking имеет 100+ интеграций. Maintenance стоимость растёт быстрее operational efficiency.

Event bus превращает события в first-class objects: producer публикует, любое количество consumers подписывается.

Структурные элементы

Topics. payments.transfer.completed, loan.application.received, card.transaction.authorized, aml.alert.raised, fraud.case.opened.

Schema registry. Контракты для каждого event type, versioning.

Producer guarantees. At-least-once, idempotent IDs, ordering в partition.

Consumer patterns. Каждый consumer держит offset, может re-process.

Dead letter queue для unprocessable.

Observability — throughput, lag, error rates per topic.

Banking-specific concerns

Sensitivity. Payment events содержат PII — encryption mandatory, access control строгий.

Ordering. Transaction posting должно быть strictly ordered per account.

Auditability. Каждое event traced для regulator audit.

Latency. Real-time fraud detection требует events < 100ms от source.

Reconciliation. Events vs ledger — discrepancies must be detectable.

Где обычно ломается

Bus есть, но contracts нет — schema changes break consumers.

Topic naming chaos — каждая команда invents.

Owner отсутствует — schema changes без согласования.

PII в clear text — security incident waiting.

Critical flow с too-loose semantic — payment posted twice через retry.

Governance

Каждый topic имеет owner.

Schema changes — PR review с consumer acknowledgement.

PII — encrypted, access controlled.

Operating routine — weekly top consumers/producers, lag review.

Связанное

• /architecture/banking-around-core-architecture/ — wrap core
• /architecture/banking-cdp-architecture/ — CDP consumer
• /architecture/banking-realtime-decisioning/ — decisioning consumer
• /insights/banking-integration-debt/ — integration debt