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withsoon/System Design/Netflix Data EngineeringPRODUCTION

Governance / Quality

Cover data contracts, DQ dashboards, PII policy, deletions, lineage, audits, and severity-driven response paths.

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Data contracts

PRODUCTIONChapter 128 min

Treat schema, privacy, freshness, and trust as first-class product surfaces.

Schema contracts, DQ checks, privacy controls, and audit trails are not side notes here; they are operating requirements of the platform.

PRODUCTION8 minTreat schema, privacy, freshness, and trust as first-class product surfaces.

Quick jumps

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Monthly users

200M-250M

Docs use both 200M+ and 250M assumptions

Daily active users

80M

Used for heartbeat and Kafka math

Peak concurrency

15M

Useful for QoE and live ops workloads

Data contracts

Put contracts before dashboards of trust

If schemas and ownership are weak, downstream quality is always reactive.

Ownership

Every event family names an owning team, schema steward, and paging contact before it can publish into the platform.

Schema rules

Required fields, enum compatibility, timestamp semantics, and PII tags are validated before events reach durable topics.

Breaking change path

Breaking changes fork versioned schemas or topics, notify downstream owners, and block deploys until compatibility checks pass.

DQ dashboard

Make quality visible like a production surface

The page should show DQ as a system with severity, not a checklist hidden in prose.

Investigation path

Duplicate rate

Possible causes: missing Kafka partition, Flink lag, schema change, bad dedupe logic, content dimension join failure, or late-event spike.

1

Kafka lag

2

Flink checkpoint health

3

Bronze volume completeness

4

Silver DQ results

5

Gold aggregate publish

Severity cards

P0

Gold table missing or official metric broken

PagerDuty + incident commander

P1

Watch hours dropped 40% or freshness breach

Slack + PagerDuty

P2

Null rate increased or late events spiked

Slack + Jira

P3

Non-critical metadata missing

Backlog / Jira only

Privacy controls

Keep governance and privacy operational

PII, deletes, retention, and access controls must feel concrete.

PII classification matrix

Field policy

email

Direct PII

Never expose raw email in analytics marts

Hash or tokenize before warehouse storage

Restrict raw access to a minimal approved set of services

Must include

Encryption at rest and in transit

RBAC plus row-level and column-level security

Retention policies by data class and layer

GDPR / right-to-delete propagation across lakehouse, warehouse, and feature stores

Audit logs for data access and correction workflows

Regional data residency where required

Say this

Use a trust-and-governance framing line

Good answers make contracts, quality, and privacy feel core to the design.

Say This In Interview

Schema contracts, DQ checks, privacy controls, and audit trails are not side notes here; they are operating requirements of the platform.

Last reviewed June 2026 Β· By Prasoon Parashar

Numbers are interview assumptions, not real Netflix internal figures.

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