Learning path
Data Engineer learning path: everything to study, topic by topic
Comprehensive Data Engineer assessment covering pipeline design, data modeling and storage, SQL transformations, streaming and real-time processing, infrastructure operations, and data governance.
Short answer
To learn Data Engineer, work through 6 modules and 45 topics in the order they build on each other. It starts with Data Pipeline Design, then moves on to Data Modeling & Storage and SQL & Transformation. Use the map as a checklist, or measure your level and study only what is missing.
What you will study
Topics are grouped by module. Open one to see its objectives and key concepts.
1 · Data Pipeline Design6 topics
ETL vs ELT Patterns
ETL vs ELT architectures, transformation placement, staging strategies, incremental loading, and medallion architecture patterns
Objectives
- Choose between ETL and ELT based on infrastructure and use-case constraints
- Design data pipeline layers with appropriate transformation staging
Key concepts
- ETL vs ELT
- transformation layers
- staging areas
- incremental loading
- full refresh
- medallion architecture
- data validation
Batch Processing Fundamentals
Batch job design, scheduling strategies, data partitioning for batch workloads, checkpoint/restart patterns, and MapReduce concepts
Objectives
- Design batch processing pipelines with proper error handling and restart logic
- Understand trade-offs between batch window sizes and data freshness
Key concepts
- batch job design
- scheduling strategies
- checkpoint/restart
- MapReduce
- data partitioning
- backfill strategies
- parallel processing
Pipeline Orchestration (Airflow/Dagster/Prefect)
DAG design, scheduling, dependency management, retry policies, backfill, SLA monitoring, and orchestrator selection criteria
Objectives
- Design DAGs with proper dependency management and failure handling
- Compare orchestration tools and choose based on team constraints
Key concepts
- DAG design
- Airflow operators
- Dagster assets
- Prefect flows
- retry policies
- backfill
- SLA monitoring
- task isolation
Idempotent & Retry-Safe Pipelines
Idempotent pipeline design, deduplication strategies, upsert patterns, watermark-based processing, and exactly-once batch semantics
Objectives
- Design idempotent data pipelines that produce consistent results on re-execution
- Implement deduplication strategies for at-least-once delivery systems
Key concepts
- idempotency
- deduplication
- upsert patterns
- watermarks
- deterministic processing
- checkpoint recovery
- at-least-once delivery
Data Contracts & Schema Evolution
Producer-consumer contracts, schema enforcement, backward/forward compatibility, breaking change management, and contract testing
Objectives
- Design data contracts that protect downstream consumers from breaking changes
- Implement schema evolution strategies with compatibility guarantees
Key concepts
- data contracts
- producer ownership
- consumer SLAs
- schema enforcement
- backward compatibility
- forward compatibility
- contract testing
Reverse ETL
Syncing analytical warehouse data back to operational tools (CRMs, marketing platforms), Census/Hightouch patterns, activation use cases, and sync strategies
Objectives
- Design reverse ETL pipelines that sync warehouse data to operational tools reliably
- Choose appropriate sync strategies and handle conflicts between warehouse and operational systems
Key concepts
- reverse ETL patterns
- data activation
- Census
- Hightouch
- sync modes
- audience segmentation
- operational analytics
2 · Data Modeling & Storage7 topics
Dimensional Modeling (Star/Snowflake)
Star schema, snowflake schema, fact and dimension tables, grain definition, Kimball methodology, and conformed dimensions
Objectives
- Design dimensional models with correct grain definition
- Choose between star and snowflake schemas based on query patterns
Key concepts
- star schema
- snowflake schema
- fact tables
- dimension tables
- grain definition
- Kimball methodology
- conformed dimensions
Data Lake vs Warehouse vs Lakehouse
Architecture comparison of data lakes, warehouses, and lakehouse patterns, including medallion architecture and cost-performance trade-offs
Objectives
- Compare lake, warehouse, and lakehouse architectures for different workloads
- Design a medallion architecture for a lakehouse platform
Key concepts
- data lake
- data warehouse
- lakehouse
- medallion architecture
- schema-on-read
- schema-on-write
- separation of storage and compute
File Formats (Parquet/Avro/ORC)
Columnar vs row-based formats, compression codecs, schema evolution support, read/write performance, and format selection criteria
Objectives
- Choose the right file format based on read/write patterns and use case
- Understand how compression and encoding affect performance
Key concepts
- Parquet
- Avro
- ORC
- columnar storage
- row-based storage
- compression codecs
- schema evolution
- predicate pushdown
Partitioning & Bucketing Strategies
Table partitioning strategies, bucket/cluster strategies, partition pruning, small file problem, and partition evolution
Objectives
- Design partitioning strategies that optimize query performance
- Diagnose and resolve the small file problem in data lakes
Key concepts
- partition pruning
- bucketing
- clustering
- small file problem
- partition evolution
- dynamic partitioning
- over-partitioning
Open Table Formats (Iceberg/Delta/Hudi)
Apache Iceberg, Delta Lake, Apache Hudi — ACID transactions on data lakes, time travel, schema evolution, and format comparison
Objectives
- Compare Iceberg, Delta, and Hudi for different lakehouse use cases
- Leverage time travel and schema evolution for reliable data lakes
Key concepts
- Apache Iceberg
- Delta Lake
- Apache Hudi
- ACID transactions
- time travel
- schema evolution
- hidden partitioning
- copy-on-write vs merge-on-read
Lakehouse Architecture
Designing lakehouse architectures using Delta Lake, Apache Iceberg, or Apache Hudi for ACID transactions on data lakes
Objectives
- Choose and design a lakehouse architecture with the appropriate open table format
- Implement ACID transactions, schema evolution, and time travel on data lakes
Key concepts
- Delta Lake
- Apache Iceberg
- Apache Hudi
- ACID on lakes
- time travel
- schema evolution
- table format trade-offs
- merge-on-read
Cost-Effective Storage Strategies
Tiered storage architectures, lifecycle policies, compression optimization, cold/warm/hot data patterns, and storage cost modeling for data platforms
Objectives
- Design tiered storage architectures that balance query performance with cost efficiency
- Implement data lifecycle policies that automatically optimize storage costs over time
Key concepts
- tiered storage
- lifecycle policies
- compression optimization
- hot/warm/cold data
- storage cost modeling
- data retention policies
- archival strategies
3 · SQL & Transformation5 topics
Advanced SQL (Window Functions/CTEs)
Window functions, CTEs, recursive queries, lateral joins, advanced aggregations, and analytical SQL patterns
Objectives
- Write complex analytical queries using window functions and CTEs
- Solve data engineering problems with advanced SQL patterns
Key concepts
- window functions
- CTEs
- recursive queries
- ROW_NUMBER
- RANK
- LAG/LEAD
- PARTITION BY
- lateral joins
dbt & Transformation Layers
dbt project structure, models, tests, macros, incremental models, materializations, and documentation-as-code
Objectives
- Structure a dbt project with proper layering and naming conventions
- Implement incremental models with appropriate strategies
Key concepts
- dbt models
- materializations
- incremental models
- dbt tests
- Jinja macros
- ref function
- sources
- documentation-as-code
Data Quality Frameworks (Great Expectations)
Data quality dimensions, expectation suites, validation pipelines, data profiling, anomaly detection, and quality metrics
Objectives
- Design data quality validation pipelines with appropriate expectations
- Implement data profiling and anomaly detection strategies
Key concepts
- Great Expectations
- data profiling
- expectation suites
- data quality dimensions
- anomaly detection
- validation pipelines
- data observability
Slowly Changing Dimensions
SCD Types 1-6, hybrid approaches, temporal data modeling, effective dating, and bitemporal design patterns
Objectives
- Select the appropriate SCD type for given business requirements
- Implement SCD Type 2 with correct merge/upsert logic
Key concepts
- SCD Type 1
- SCD Type 2
- SCD Type 3
- SCD Type 6
- effective dating
- bitemporal modeling
- surrogate keys
Performance Optimization
Query optimization, execution plans, materialized views, index strategies, join optimization, and warehouse-specific tuning
Objectives
- Analyze and optimize slow-running queries using execution plans
- Design materialized views and indexes for common query patterns
Key concepts
- execution plans
- materialized views
- index strategies
- join optimization
- query profiling
- statistics
- warehouse tuning
- caching strategies
4 · Streaming & Real-Time7 topics
Message Queue Fundamentals (Kafka/Kinesis)
Kafka architecture, topics, partitions, consumer groups, Kinesis streams, offset management, and message ordering
Objectives
- Design Kafka topic configurations for different throughput and ordering needs
- Manage consumer groups and offset strategies for reliable consumption
Key concepts
- Kafka topics
- partitions
- consumer groups
- offset management
- Kinesis streams
- shards
- message ordering
- retention policies
Stream Processing (Flink/Spark Streaming)
Stream processing frameworks, windowing strategies, watermarks, event-time vs processing-time, and stateful processing
Objectives
- Design stream processing pipelines with appropriate windowing strategies
- Handle late-arriving data with watermarks and allowed lateness
Key concepts
- Apache Flink
- Spark Structured Streaming
- windowing
- tumbling windows
- sliding windows
- session windows
- watermarks
- event-time processing
Change Data Capture (Debezium)
CDC patterns, Debezium connectors, log-based CDC, snapshot strategies, schema change handling, and CDC pipeline architectures
Objectives
- Design CDC pipelines that reliably capture database changes
- Handle schema changes and initial snapshots in CDC architectures
Key concepts
- Debezium
- log-based CDC
- WAL reading
- snapshot strategies
- schema change handling
- CDC to lakehouse
- outbox pattern
Exactly-Once Semantics
Exactly-once processing guarantees, transactional producers, idempotent consumers, two-phase commit, and end-to-end guarantees
Objectives
- Design systems with exactly-once processing guarantees end to end
- Understand the performance cost of exactly-once vs at-least-once
Key concepts
- exactly-once semantics
- transactional producers
- idempotent consumers
- two-phase commit
- Kafka transactions
- end-to-end guarantees
- deduplication keys
Real-Time Serving Layer
Real-time feature stores, materialized views for serving, CQRS patterns, speed layer, and serving layer architectures
Objectives
- Design real-time serving architectures for low-latency data access
- Compare Lambda vs Kappa architecture for real-time analytics
Key concepts
- feature stores
- materialized views
- CQRS
- speed layer
- Lambda architecture
- Kappa architecture
- serving layer
- low-latency queries
Event-Driven Data Architecture
Event sourcing for analytics, CQRS patterns applied to data platforms, event stores, temporal queries, and rebuilding state from event logs
Objectives
- Design event-driven data architectures that support temporal queries and state rebuilding
- Apply CQRS patterns to separate read-optimized analytics from write-optimized ingestion
Key concepts
- event sourcing
- CQRS for data
- event stores
- temporal queries
- event replay
- aggregate projections
- event schema evolution
Real-Time Analytics Architecture
OLAP engines (ClickHouse, Apache Druid, Pinot), materialized views, pre-aggregation strategies, and sub-second query architectures for analytics
Objectives
- Choose and design real-time OLAP architectures for sub-second analytical queries
- Implement pre-aggregation and materialized view strategies that balance freshness with performance
Key concepts
- ClickHouse
- Apache Druid
- Apache Pinot
- materialized views
- pre-aggregation
- OLAP engines
- sub-second queries
5 · Infrastructure & Operations8 topics
Cloud Data Services (S3/GCS/ADLS)
Object storage patterns, cloud data services comparison, data lake storage design, lifecycle policies, and access control
Objectives
- Design cloud storage architectures for data lake workloads
- Configure lifecycle policies and access control for data security
Key concepts
- S3
- GCS
- ADLS
- object storage
- lifecycle policies
- storage classes
- access control
- cross-region replication
Spark Cluster Management
Spark architecture, cluster sizing, memory management, shuffle optimization, dynamic allocation, and Spark on Kubernetes
Objectives
- Size and configure Spark clusters for different workload profiles
- Diagnose and resolve common Spark performance bottlenecks
Key concepts
- Spark architecture
- executors
- driver memory
- shuffle optimization
- dynamic allocation
- Spark on Kubernetes
- EMR/Dataproc
- spot instances
Cost Optimization for Data Workloads
Cost modeling for data platforms, storage tiering, compute optimization, reserved capacity, and FinOps practices for data teams
Objectives
- Design cost-efficient data platform architectures with proper tiering
- Implement FinOps practices for data team cost visibility
Key concepts
- storage tiering
- compute optimization
- reserved capacity
- spot instances
- FinOps
- cost attribution
- auto-scaling
- workload scheduling
DataOps & CI/CD for Pipelines
CI/CD for data pipelines, testing strategies, environment management, blue-green deployments, and data pipeline versioning
Objectives
- Design CI/CD pipelines for data transformation code and infrastructure
- Implement testing strategies that catch data quality issues before production
Key concepts
- DataOps
- pipeline testing
- data unit tests
- integration testing
- environment management
- blue-green deployments
- pipeline versioning
- feature flags for data
Data Platform Architecture
End-to-end data platform design, technology selection, scalability, multi-tenancy, and self-service data infrastructure
Objectives
- Design end-to-end data platform architectures for enterprise scale
- Build self-service data infrastructure that enables autonomous teams
Key concepts
- platform architecture
- technology selection
- scalability
- multi-tenancy
- self-service
- data catalog
- metadata management
- platform team structure
Data Observability
Monitoring data pipelines for anomalies, implementing freshness/volume/schema checks, alerting on data quality regressions, and building observability platforms
Objectives
- Design a data observability strategy covering freshness, volume, and schema dimensions
- Implement automated alerting for data quality regressions with minimal false positives
Key concepts
- data freshness monitoring
- volume anomaly detection
- schema change detection
- data SLAs
- observability platforms
- Monte Carlo
- data downtime
Data API Design
Building data APIs for internal consumers, GraphQL for data access, API-first analytics, rate limiting, caching strategies, and API versioning for data products
Objectives
- Design performant data APIs with appropriate caching and rate limiting strategies
- Choose between REST and GraphQL for different data access patterns
Key concepts
- data APIs
- GraphQL for data
- API-first analytics
- rate limiting
- caching strategies
- API versioning
- data product endpoints
DataOps Testing Strategies
Unit testing data transformations, integration testing pipelines, data mocking frameworks, test data generation, and CI/CD for data quality
Objectives
- Design comprehensive testing strategies for data pipelines covering unit and integration tests
- Implement data mocking and test data generation for reproducible pipeline testing
Key concepts
- unit testing data
- integration testing pipelines
- data mocking
- test data generation
- dbt tests
- great expectations tests
- pipeline regression testing
6 · Governance & Compliance12 topics
Data Lineage & Cataloging
Data lineage tracking, metadata catalogs, impact analysis, data discovery, and lineage integration with orchestration tools
Objectives
- Design data lineage tracking across batch and streaming pipelines
- Implement metadata catalogs that enable data discovery and impact analysis
Key concepts
- data lineage
- data catalog
- impact analysis
- data discovery
- OpenLineage
- Apache Atlas
- column-level lineage
- metadata management
PII Handling & Masking
PII detection, data masking techniques, tokenization, encryption at rest/transit, and anonymization strategies
Objectives
- Design PII handling pipelines with appropriate masking and encryption
- Choose between anonymization, pseudonymization, and tokenization
Key concepts
- PII detection
- data masking
- tokenization
- encryption at rest
- encryption in transit
- anonymization
- pseudonymization
- dynamic masking
GDPR/CCPA Compliance for Data
Right to erasure implementation, consent management in data pipelines, data retention policies, and cross-border data transfer
Objectives
- Implement right-to-erasure pipelines across distributed data systems
- Design data retention policies that comply with GDPR and CCPA
Key concepts
- right to erasure
- consent management
- data retention
- cross-border transfer
- data subject requests
- privacy by design
- data processing agreements
Data Mesh Principles
Domain-oriented data ownership, data as a product, self-serve data platform, federated governance, and organizational adoption patterns
Objectives
- Apply data mesh principles to decentralize data ownership
- Design federated governance models that balance autonomy and standards
Key concepts
- domain ownership
- data as a product
- self-serve platform
- federated governance
- data mesh vs data fabric
- domain boundaries
- interoperability standards
Data Product Thinking
Data product definition, SLOs for data products, discoverability, interoperability, and data product lifecycle management
Objectives
- Define and manage data products with clear SLOs and ownership
- Design data product platforms that enable autonomous data teams
Key concepts
- data product definition
- data product SLOs
- discoverability
- interoperability
- data product lifecycle
- data product canvas
- data product owner
Data Mesh Architecture
Designing and implementing Data Mesh: domain ownership, data products, federated governance, and self-serve infrastructure
Objectives
- Design a domain-oriented data mesh with clear ownership and governance boundaries
- Build self-serve data infrastructure that enables domain teams to publish data products
Key concepts
- domain ownership
- data products
- federated governance
- self-serve platform
- data product contracts
- interoperability
- mesh topology
Real-Time Feature Stores
Building and operating feature stores (Feast, Tecton) for real-time ML feature serving with point-in-time correctness
Objectives
- Design a feature store with online/offline consistency and point-in-time correctness
- Prevent training-serving skew in ML feature pipelines
Key concepts
- online/offline stores
- point-in-time joins
- feature freshness
- Feast
- Tecton
- backfilling
- training-serving skew prevention
Data Quality at Scale
Implementing data quality frameworks at scale using Great Expectations, dbt tests, and anomaly detection
Objectives
- Design a data quality framework with automated validation and alerting at scale
- Implement lineage-aware quality checks that surface root causes across the pipeline
Key concepts
- Great Expectations
- data contracts
- schema validation
- freshness checks
- anomaly detection
- data quality SLAs
- lineage-aware quality
Data Governance & Catalog Systems
Implementing enterprise data governance: data cataloging (Datahub, Amundsen), lineage tracking, classification, and access policies
Objectives
- Design and implement an enterprise data catalog with lineage and classification
- Define access policies and governance workflows for sensitive data at scale
Key concepts
- data catalog
- lineage graphs
- data classification
- PII tagging
- access policies
- Datahub
- Amundsen
- OpenMetadata
Data Lake Security & Access Control
Fine-grained access control for data lakes, column masking, row-level security, encryption at rest/transit, and multi-tenant data isolation
Objectives
- Design fine-grained access control for data lakes with row and column-level security
- Implement multi-tenant data isolation while maintaining query performance
Key concepts
- row-level security
- column masking
- fine-grained ACLs
- data encryption
- multi-tenant isolation
- Apache Ranger
- Lake Formation
Metadata Management
Metadata stores, active metadata for automation, automated cataloging, metadata-driven pipelines, and business glossary management
Objectives
- Design a metadata management strategy that enables automated discovery and governance
- Implement active metadata patterns that drive pipeline behavior and quality checks
Key concepts
- active metadata
- metadata stores
- automated cataloging
- metadata-driven pipelines
- business glossary
- OpenMetadata
- metadata graph
Data Team Collaboration
Working effectively with data analysts and scientists, defining data SLAs, establishing data contracts between teams, and managing data product ownership
Objectives
- Establish effective data SLAs and contracts between engineering and analytics teams
- Design self-serve data access workflows that reduce friction for data consumers
Key concepts
- data SLAs
- cross-team contracts
- data product ownership
- analyst enablement
- self-serve data access
- data request workflows
- documentation standards
Levels: Junior, Mid, Senior, and Expert
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Frequently asked questions
Where should I start studying Data Engineer?
Start with Data Pipeline Design: ETL vs ELT Patterns, Batch Processing Fundamentals, and Pipeline Orchestration (Airflow/Dagster/Prefect). The map orders topics by what they depend on, so each one prepares the next.
How long does a full Data Engineer assessment take?
A full assessment of this path takes about 55 minutes. Study time depends on where you start; a diagnostic shows which topics you can skip.
Do I need an account to use this page?
No. The map, objectives and key concepts are open. You only need an account to be measured, get your gap by topic and receive a plan.