Machine Learning

What Is Data Engineering? Roles, Tools & Pipelines

What is data engineering? Learn what data engineers do, the tools they use, and when your company needs one. A practical guide for business leaders and CTOs.

Andrew Martin
12 min read
Data engineering pipelines with glowing nodes and data flows on a deep blue gradient background

Don't Hire a Data Scientist Before a Data Engineer

Building ML models on unreliable pipelines fails every time. Fix your data infrastructure first — a data engineer is almost always the right first data hire.

Every business decision that depends on data — a forecast, a churn model, a revenue dashboard — ultimately rests on a foundation built by data engineers. If that foundation is unstable, every model, report, and analysis built on top of it is compromised.

Data engineering is one of the most critical yet least understood roles in the modern data stack. Business leaders know they need data scientists. They often underestimate how much of a data scientist’s time gets burned cleaning unreliable pipelines — or how quickly that problem disappears with the right infrastructure hire.

This guide covers what data engineering is, what data engineers actually do day-to-day, which tools define the modern stack, and how to decide when your company needs one.

What Is Data Engineering?

Data engineering is the practice of designing, building, and maintaining the infrastructure, systems, and pipelines that collect, transport, store, and prepare data for downstream use. Data engineers are the architects of your data ecosystem — they ensure that analysts, data scientists, and business intelligence tools receive clean, reliable, timely data, regardless of source complexity or volume.

The discipline sits at the intersection of software engineering and data management. Unlike data analysts, who interpret existing data to answer business questions, or data scientists, who build predictive models on top of prepared datasets, data engineers focus on the infrastructure layer beneath both.

The Core Problem Data Engineering Solves

Most organizations collect data from dozens of disconnected sources: a CRM, a transactional database, a marketing platform, a product analytics tool, a payment processor. Each system has its own schema, update frequency, data quality standards, and API quirks.

Without data engineering, this creates a fragmented landscape where:

  • Analysts spend 40–60% of their time wrangling raw data rather than analyzing it (per Anaconda’s State of Data Science report)
  • Different teams run the same reports and get different numbers
  • Machine learning models train on stale or corrupted inputs
  • Business leaders lose confidence in data-driven decisions

Data engineers solve this by building pipelines that automate the movement and transformation of data, enforcing quality standards, and delivering clean datasets to wherever they’re needed.

Data Engineering vs. Adjacent Data Roles

The data team ecosystem has three distinct roles that are frequently confused:

  • Data engineers: Build and maintain pipelines, storage systems, and data infrastructure
  • Data analysts: Query prepared data to answer business questions and create reports
  • Data scientists: Build statistical models and ML systems on top of prepared data

A useful mental model: data engineers build the roads, data analysts drive on them to deliver reports, and data scientists use the same roads to explore new destinations. If the roads are potholed and unmapped, nobody moves fast.

Understanding data science vs machine learning clarifies where each role fits in a mature data organization.

What Data Engineers Actually Do

Data engineers own the full lifecycle of data movement — from ingestion at the source to delivery at the destination. Their day-to-day work combines software engineering rigor with deep knowledge of distributed systems, database design, and data quality management.

The core output of a data engineer’s work is a data pipeline: an automated sequence of steps that extracts data from one or more sources, applies transformations, and loads the result into a target system on a defined schedule or in real time.

Core Responsibilities

Pipeline development and maintenance: Writing, testing, and operating the code that moves data between systems. A single data engineer may own dozens of pipelines simultaneously, each with its own failure modes.

Data modeling: Designing how data is structured in the warehouse — which tables exist, how they relate, what aggregations are pre-computed. Good data models make analyst queries fast and intuitive. Poor models create reporting nightmares.

Data quality monitoring: Building automated checks that detect schema changes, null values, duplicates, and statistical anomalies before bad data reaches downstream consumers. According to McKinsey’s State of AI 2024, poor data quality is cited as a top barrier to successful AI implementation by 65% of organizations using AI regularly.

Infrastructure management: Provisioning and configuring the storage, compute, and orchestration infrastructure — cloud data warehouses, Kubernetes clusters for processing jobs, monitoring and alerting systems.

Collaboration with analysts and scientists: Translating downstream data needs into pipeline specifications. A data scientist who needs a feature-engineered dataset for a churn model works with data engineers to get it built reliably.

The Data Engineering Mindset

Data engineering differs from general software engineering in emphasis. The primary concerns are:

  • Reliability: Pipelines must run consistently, with alerts when they fail and recovery mechanisms when they don’t
  • Scalability: Systems must handle 10x or 100x data volume growth without architectural rewrites
  • Observability: Every pipeline should emit metrics that make failures visible before users notice them
  • Idempotency: Running a pipeline twice should produce the same result as running it once

Understanding whether data science requires coding also applies here — data engineering is fundamentally an engineering discipline, and Python and SQL are non-negotiable.

The Data Engineering Stack

The modern data engineering stack is organized into four functional layers: ingestion, orchestration, storage, and transformation. Data engineers combine tools from each layer to build complete data systems.

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Orchestration and Pipeline Tools

Apache Airflow is the most widely adopted open-source workflow orchestration tool. Engineers write pipelines as directed acyclic graphs (DAGs) in Python, defining dependencies between tasks and scheduling execution. Airflow’s documentation covers its core abstractions well. Managed versions include Astronomer (cloud Airflow) and AWS MWAA.

Prefect and Dagster offer modern alternatives with stronger observability and developer experience, particularly for teams moving beyond basic scheduling toward asset-based pipelines.

Apache Kafka handles real-time streaming data — event streams from applications, clickstreams from web analytics, sensor data from IoT devices. Where Airflow processes data in scheduled batches, Kafka enables sub-second data movement for use cases like fraud detection and real-time personalization. The Stack Overflow Developer Survey 2024 consistently ranks Kafka among the most-used data technologies by professional developers.

Storage, Transformation, and Warehousing

Apache Spark is the dominant distributed processing framework for large-scale data transformation. Spark runs Python, SQL, or Scala code across clusters of machines, enabling petabyte-scale transformations that would be impossible on a single server.

dbt (data build tool) has become the standard for SQL-based transformation inside data warehouses. Engineers define transformation logic in SQL files, and dbt compiles and runs them against the warehouse while enforcing testing, documentation, and lineage tracking. Per dbt’s documentation, the tool is now used by over 50,000 companies globally.

Cloud data warehouses — Snowflake, Google BigQuery, or Amazon Redshift — serve as the central storage layer where transformed data lives and analysts query it. Databricks combines data lakehouse storage with Spark compute, popular in organizations running heavy ML workloads.

Ingestion and Integration

Fivetran, Airbyte, and Stitch provide pre-built connectors that extract data from SaaS tools (Salesforce, HubSpot, Stripe, Google Analytics) and load it into the warehouse. These ELT (extract-load-transform) tools dramatically reduce the engineering time required to onboard new data sources.

For companies managing CRM data pipelines, connecting these ingestion tools to best-in-class CRM software is a common early engineering project.

ToolCategoryPrimary Use CasePricing Model
Apache AirflowOrchestrationBatch pipeline schedulingOpen source + managed
Apache KafkaStreamingReal-time event processingOpen source + managed
Apache SparkProcessingLarge-scale transformationOpen source + managed
dbtTransformationSQL-based data modelingOpen source + paid tiers
SnowflakeWarehousingCloud data storage + queryPay-per-usage
Google BigQueryWarehousingServerless analyticsPay-per-query
DatabricksLakehouseML + analytics unifiedCompute-based
FivetranIngestionSaaS data connectorsMonthly active rows
AirbyteIngestionOpen source connectorsOpen source + cloud

Data Engineering vs Data Science vs Data Analytics

Data engineering, data science, and data analytics are distinct disciplines that work together in a functioning data organization. The three roles are frequently conflated by leadership, which leads to poor hiring decisions, role confusion, and underperforming teams.

The key distinction: data engineers build the system that delivers data; data analysts use that system to answer questions; data scientists use that system to build predictive models. All three roles require SQL and Python at varying depths, but the emphasis and daily work diverge significantly.

Refer to the full comparison in our guide on data science vs data analytics for the analyst-side breakdown.

The Three-Role Comparison

DimensionData EngineerData ScientistData Analyst
Primary focusBuild infrastructure and pipelinesBuild predictive models and run experimentsAnswer business questions with existing data
Core languagesPython, SQL, Scala, JavaPython, R, SQLSQL, Python (lighter), BI tools
Key toolsAirflow, Spark, Kafka, dbt, Snowflakescikit-learn, PyTorch, TensorFlow, JupyterTableau, Power BI, Looker, Excel
OutputReliable data pipelines and warehousesML models, statistical analyses, forecastsDashboards, reports, ad hoc analyses
Education backgroundComputer science, software engineeringStatistics, mathematics, data scienceBusiness, economics, statistics
Typical US salary$110K–$165K$120K–$175K$70K–$120K
Coding depthDeep (software engineering practices)Deep (statistical and ML libraries)Moderate (query-focused)
Infra ownershipHighLow to moderateLow
CollaborationAnalysts, scientists, platform teamsData engineers, product, leadershipBusiness stakeholders, analysts

Team Structure Models

Small team (5–20 employees): One generalist data analyst handles most reporting. Data engineering work is done by a backend engineer on a best-effort basis. Pipelines are fragile and often held together by scheduled scripts.

Growth stage (20–100 employees): The first dedicated data hire should usually be a data engineer. They stabilize the infrastructure that enables every other data role. A second hire is typically a data analyst.

Scale (100+ employees): Specialized data engineering teams (often 2–5 engineers) support dedicated analyst and data science teams. Platform engineering may own infrastructure; data engineers own the pipelines.

Common mistake: Hiring a data scientist as the first data hire is one of the most expensive mistakes a growing company makes. A data scientist without clean pipelines spends the majority of their time doing data engineering work they weren’t hired for.

When to Hire a Data Engineer

Hiring a data engineer is the right move when your organization reaches a point where data infrastructure complexity is meaningfully slowing down decisions. This typically happens earlier than most leadership teams expect.

According to the BLS Occupational Outlook for Data Scientists, the broader data professional category is projected to grow 35% through 2032 — among the fastest growth rates across all occupational categories. Data engineering is a central driver of that growth, as every organization building AI and analytics capabilities needs reliable pipelines beneath them.

Five Signals That Indicate You Need a Data Engineer

1. Analysts spend significant time cleaning data. If your analysts are building one-off scripts to reconcile data from different sources, that’s engineering work being done at the wrong level.

2. Different teams get different numbers from the same report. Inconsistent definitions and logic scattered across spreadsheets and dashboards is a data modeling problem that only structured pipelines solve.

3. You have more than three data sources feeding business decisions. A CRM, a product database, a marketing platform, and an accounting system are four sources — managing their integration manually is a full-time job.

4. Your AI or ML initiatives are stalling. Per McKinsey’s State of AI 2024, data quality and pipeline reliability are among the top reasons ML projects fail to reach production. If a data scientist can’t trust the training data, the model can’t be trusted either. Connecting data infrastructure to content marketing analytics or Google Analytics 4 data flows requires the same pipeline discipline.

5. You’re building toward a data warehouse. If leadership has decided to centralize reporting in a warehouse (Snowflake, BigQuery, Redshift), a data engineer should design and build it from the start. Retrofitting a poorly designed warehouse is significantly more expensive than building it correctly.

Hiring Budget and Timeline

A junior data engineer (1–3 years experience) costs $90K–$120K in the US, AUD $110K–$145K in Australia. A senior engineer with distributed systems experience typically commands $140K–$180K. These figures are consistent with compensation data from Glassdoor and LinkedIn’s 2024 salary benchmarks.

Expect a 60–90 day ramp before a new data engineer is delivering production pipelines. For most companies at the tipping point, the ROI — measured in analyst hours recovered, model reliability improved, and reporting confidence gained — is visible within the first quarter.

For comparison, see how the hiring timeline and decision criteria differ when hiring a data scientist vs. a data engineer.

Data Engineering vs Data Science: Which First?

This is the most common strategic question GrowthGear encounters when advising data-team buildouts. The answer is almost always: data engineering first.

The logic is simple: a data scientist working on clean, well-modeled data is productive from day one. A data scientist working on raw, inconsistent, undocumented data spends 60–80% of their time doing data engineering. Worse, they build that infrastructure once, informally, in a way that doesn’t scale — and it eventually has to be rebuilt properly anyway.

Build the foundation before the model. A stable data infrastructure is a prerequisite for everything that depends on it, including the machine learning work described in our guide on data science vs machine learning.

Data Engineering in Practice: Summary

AspectWhat It Means in Practice
Role definitionBuilds, maintains, and scales data pipelines and infrastructure
Core deliverableReliable, timely, clean data for analysts and scientists
Primary languagesPython, SQL (essential); Scala, Java (for Spark)
Orchestration toolApache Airflow (most common), Prefect, Dagster
Processing frameworkApache Spark (batch); Apache Kafka (streaming)
Transformation layerdbt (SQL-based data modeling in the warehouse)
Storage targetsSnowflake, BigQuery, Redshift, Databricks
Ingestion approachFivetran, Airbyte (SaaS connectors); custom APIs (internal systems)
First hire signal3+ data sources, analysts wrangling data, inconsistent reporting
US salary range$90K–$180K (junior to senior)
Australia salary rangeAUD $110K–$185K
Relationship to MLPrerequisite — clean pipelines enable reliable model training

Take the Next Step

Data engineering isn’t just a technical problem — it’s a business problem. Unreliable pipelines slow every AI initiative, inflate analyst costs, and erode confidence in data-driven decisions.

Whether you’re building your first data team, evaluating a data warehouse migration, or trying to understand why your ML models aren’t performing, GrowthGear can help you assess what’s actually needed and build a roadmap that matches your stage.

Book a Free Strategy Session →


Sources & References

  1. Apache Airflow Documentation — Core workflow orchestration framework for data pipeline scheduling (2024)
  2. dbt Documentation — What is dbt? — Used by 50,000+ companies globally for SQL-based data transformation (2024)
  3. Stack Overflow Developer Survey 2024 — SQL and Python usage rates among professional developers and data practitioners (2024)
  4. BLS Occupational Outlook Handbook: Data Scientists — 35% job growth projected through 2032 for data professional roles (2023)
  5. McKinsey State of AI 2024 — 65% of organizations regularly use generative AI; data quality cited as top implementation barrier (2024)

Frequently Asked Questions

Data engineering is the practice of building systems that collect, store, and prepare data for analysis. Data engineers create the pipelines and infrastructure that make data usable by analysts and data scientists.

Data engineers build the infrastructure and pipelines that deliver clean data. Data scientists analyze that data to build models and extract insights. Engineers focus on reliability and scale; scientists focus on statistical modeling.

Core tools include Apache Airflow (orchestration), Apache Spark (processing), dbt (transformation), Kafka (streaming), and Snowflake or BigQuery (warehousing). SQL and Python are universal across all data engineering roles.

Glassdoor and LinkedIn 2024 salary data shows US data engineers earning $110K–$165K median. Senior engineers at large tech firms reach $180K–$250K. Australian data engineers typically earn AUD $120K–$185K.

Hire a data engineer when you have 3+ disconnected data sources, analysts spending 20%+ of their time cleaning data, or inconsistent reporting slowing decisions. Most companies reach this point at 30–50 employees.

ETL stands for Extract, Transform, Load — pulling data from source systems, cleaning and reshaping it, then loading it into a warehouse. Modern teams often use ELT instead, loading raw data first and transforming it in the warehouse.

Different rather than harder. Data engineering emphasizes software engineering, systems design, and distributed computing. Data science emphasizes statistics and ML modeling. Both require Python and SQL, but the depth differs significantly by role.