Senior Data Engineer – Python

Citigroup Inc.; Mississauga; On-site; CAD 167,000 - 236,000; Full time

Job summary

Citigroup Inc. in Mississauga seeks a Senior Data Engineer with strong Python expertise to design and scale data pipelines powering analytics and decision-making across the enterprise.

You will build PySpark workflows, optimize SQL and ETL processes, work with MongoDB, Databricks or Starburst, and collaborate with data scientists, analysts, and engineers to deliver reliable data solutions.

Qualifications

• 6+ years in software or data engineering.
• Hands-on Python data engineering, SQL, ETL design.
• Production-grade data pipelines at enterprise scale.
• Relational (PostgreSQL, Oracle, SQL Server) and NoSQL (MongoDB) experience.
• Regulated environments, preferably Financial Services.

Responsibilities

• Design, develop, and maintain scalable Python data pipelines for ingestion, transformation, and distribution across enterprise platforms.
• Build reusable Python libraries and automation utilities to support data engineering workflows.
• Develop and optimize complex SQL queries and DB objects across multiple relational databases.
• Design and implement ETL/ELT solutions including staging frameworks and error handling.
• Model data to support operational and analytical use cases.
• Work with MongoDB to design data structures for non-relational workloads.
• Build data pipelines using PySpark for large-scale distributed processing.
• Implement data quality controls to ensure accuracy and reliability.
• Collaborate with data scientists, analysts, engineers, and stakeholders to deliver data solutions.
• Contribute to CI/CD for automated testing, deployment, and version control of data workflows.
• Participate in code reviews and production support of data systems.
• Support data governance and security standards across data assets.

Skills

Python

SQL

PySpark

NoSQL MongoDB

Data Modeling

ETL/ELT Design

Education

Bachelor’s or Master’s in Computer Science / related field

Tools

Databricks

Starburst

Job description

We are seeking a skilled and experienced Senior Data Engineer with strong Python expertise to join our Engineering team. The ideal candidate is passionate about building robust, scalable data pipelines and platforms that power analytics, business intelligence, and data-driven decision-making across the enterprise. This role requires deep hands-on experience in Python-based data engineering, SQL development, data modeling, and ETL/ELT design, along with familiarity with both relational and NoSQL databases. Experience with Big Data technologies such as PySpark, and exposure to platforms like Databricks or Starburst, will be considered a strong advantage. The successful candidate will thrive in a collaborative, fast-paced environment and take ownership of end-to-end data solutions.

Responsibilities

• Design, develop, and maintain scalable Python-based data pipelines for ingestion, transformation, and distribution of data across enterprise platforms.

• Build reusable Python libraries, frameworks, and automation utilities to support data engineering workflows.

• Develop and optimize complex SQL queries, stored procedures, and database objects across multiple relational database platforms.

• Design and implement ETL/ELT solutions including staging frameworks, incremental processing, data reconciliation, and error handling.

• Develop and maintain logical and physical data models to support both operational and analytical use cases.

• Work with NoSQL databases (e.g., MongoDB) to design data structures and access patterns suited to non-relational workloads.

• Build and maintain data pipelines using PySpark for large-scale distributed data processing where applicable.

• Implement data quality, validation, and completeness controls to ensure accuracy and reliability across data products.

• Collaborate with data scientists, analysts, software engineers, and business stakeholders to understand requirements and deliver high-quality data solutions.

• Contribute to CI/CD pipelines for automated testing, deployment, and version control of data workflows.

• Participate in code reviews, troubleshooting, debugging, and production support of data systems.

• Support data governance, security standards, and compliance requirements across all data assets.

Qualifications

• Strong proficiency in Python for data engineering, including data transformation, orchestration, workflow automation, and utility development.

• Expert-level SQL skills across relational databases (PostgreSQL, Oracle, SQL Server, or MySQL).

• Solid experience in data modeling - relational and dimensional modeling (Star/Snowflake schemas).

• Hands-on experience designing and building ETL/ELT pipelines using Python-based frameworks.

• Working experience with NoSQL databases, particularly MongoDB.

• Experience with PySpark and distributed data processing frameworks for large-scale data workloads is a plus.

• Familiarity with Databricks and/or Starburst is a plus.

• Hands-on experience with AI Development Tools such as Claude Code, Devin AI, Cursor, Copilot etc.

• Knowledge of data formats including Parquet, Avro, and JSON, and storage platforms such as HDFS or cloud object stores.

• Proficiency with version control (Git) and CI/CD practices for data engineering workflows.

• Familiarity with data orchestration tools such as Apache Airflow or equivalent schedulers.

• Basic working knowledge of Java is a plus.

• Strong analytical, problem-solving, and communication skills with the ability to work across technical and non-technical teams.

Experience

• 6+ years of total experience in software or data engineering.

• Hands-on experience specifically in Python-based data engineering, SQL development, ETL design, and data modeling.

• Proven experience building and maintaining production-grade data pipelines and platforms at enterprise scale.

• Demonstrated experience working with both relational (PostgreSQL, Oracle, SQL Server) and NoSQL (MongoDB) databases in real-world projects.

• Experience working in regulated or highly process-oriented environments, preferably within Financial Services.

Education

• Bachelor’s or Master’s degree in Computer Science, Software Engineering, or an equivalent technical field.

This job description provides a high-level review of the types of work performed. Other job-related duties may be assigned as required.

Job Family Group

Technology

Job Family

Applications Development

Time Type

Full time

Primary Location Full Time Salary Range:

$120,800.00 - $170,800.00

Most Relevant Skills

Please see the requirements listed above.

Other Relevant Skills

For complementary skills, please see above and/or contact the recruiter.

Automated Processing and AI

We use automated processing, including artificial intelligence, for our legitimate business interests (or our reasonable and appropriate business purposes) to identify and align the candidate's skills and abilities with a specific job opening. Additionally, if you so choose, or consent, we can match your skills and abilities to other suitable roles at Citi.

Importantly, all our hiring processes and decisions, including determining your suitability for a role, are conducted, checked, and decided by individuals. Our automated processing and AI do not involve relying on automatic or autonomous decision-making. Please refer to any Jurisdictional Considerations, with specific provisions for your country (where relevant) for further details.

This job opening is for an existing job vacancy.

Citi is an equal opportunity employer, and qualified candidates will receive consideration without regard to their race, color, religion, sex, sexual orientation, gender identity, national origin, disability, status as a protected veteran, or any other characteristic protected by law.

If you are a person with a disability and need a reasonable accommodation to use our search tools and/or apply for a career opportunity review Accessibility at Citi.

View Citi’s EEO Policy Statement and the Know Your Rights poster.