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Top 50 data streams Interview Questions

The most frequently asked data streams questions across all roles and companies, ranked by real interview frequency. Updated daily.

50questions
~7htotal time
174companies covered
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1
System DesignStart here. 47 questions · ~419 min
Scalable Real-Time Data ArchitectureHard
Recently asked

Design a scalable real-time data processing architecture with low latency, high throughput, and fault tolerance.

data processingdistributed systemsscalabilityNielsenMorningstarAAalto University
Real-Time Ingestion System DesignHard
Recently asked

Design a fault-tolerant real-time ingestion and ML processing system with low latency, scalable state, and reliable downstream outputs.

distributed systemsscalabilitydata ingestionSnowflakeViasatTatari
LLM Serving with OrchestrationHard
Recently asked

Design a real-time LLM serving platform with streaming data, intelligent routing, adaptive model selection, and reliable fallback behavior.

agent workflowsOrchestrationml inferenceIIntuitionLabs.aiThe Home DepotCircana
Ensuring Consistency Across ServicesHard

Design a reliable strategy for maintaining data consistency across multiple ML and backend services.

backend integrationsystem designdistributed systemsZZattooNNetceteraSStellar Solutions
Batch and Streaming Processing DifferencesHard
Recently asked

Explain batch versus streaming processing, including architecture, latency, correctness, cost, and operational tradeoffs.

data ingestiondata streamsarchitecture patternsAirwallex PtySuper Micro ComputerUS Department of Defense
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2
More topics3 questions · ~27 min
Detect Anomalies in Event StreamsHard
Practice

Identify missing, duplicate, null, and out-of-range events across distributed streams with an index-friendly PostgreSQL query.

missing valuesindexessqlOpenAI
Large-Scale Data Streams AlgorithmMedium
Practice
Recently asked

Process a numeric stream in one pass and compute each complete sliding-window average with bounded memory.

aggregationscalabilityData StructuresSnowflake
Anomaly Detection in Payment StreamsHard
Practice

Detect per-user payment anomalies in a stream using rolling windows and monotonic queues for efficient range checks.

aggregationalertsanomaly detectionSSezzle

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Hands-on SQL practiceWrite and run real queries in the editor. 2 drills · ~20 min
Optimizing Window Functions at ScaleHard
Practice
Practice drill

Optimize a PostgreSQL window query by reducing rows before cumulative account-level transaction calculations.

Window Functionsdatabase optimizationlarge datasetsPlaid
Optimize Slow SQL in Distributed SystemsHard
Practice
Practice drill

Rewrite a slow distributed event query using predicate pushdown, pre-aggregation, joins, and deterministic ranking.

Performance Tuningdatabase optimizationlarge datasetsFactored
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