Senior Python Engineer

Citi; Mississauga; On-site; CAD 121,000 - 171,000; Full time

Job summary

Citibank (Switzerland) AG is seeking a Senior Python Engineer in Mississauga, operating in a hybrid model. You will design, develop, and deliver scalable Python applications for risk and quantitative domains, leading architecture and hands-on implementation with modern frameworks and cloud-native patterns.

The role requires 6+ years of hands-on Python experience, expert Python 3.x skills, and strong knowledge of microservices, RESTful APIs, and CI/CD.

Qualifications

• 6+ years of hands-on Python development in application development.
• Expert-level Python 3.x proficiency with frameworks like FastAPI, Django, Flask.
• Strong knowledge of architecture principles, distributed systems, and microservices.
• Experience with CI/CD, code reviews, and secure coding practices.
• Unix/Linux proficiency and experience with cloud deployments.
• Experience with relational and NoSQL databases and RESTful APIs.

Responsibilities

• Lead implementation and architecture of Python-based services for scalable applications.
• Develop solutions adhering to standards with deep domain knowledge in risk/quantitative areas.
• Enforce SDLC best practices and contribute to code quality through reviews.
• Collaborate with Risk, Quants, FO, DevOps, and Production Support for delivery.
• Drive development for stress testing and regulatory risk projects in Market Risk.
• Manage project technical aspects including planning, governance, and ownership of initiatives.
• Deliver high-quality solutions independently in a globally distributed environment.

Skills

Python

6+ years

FastAPI

Django

Flask

REST APIs

CI/CD

Unix

PostgreSQL

NoSQL

Distributed Systems

Cloud (AWS)

Kubernetes

Testing (PyTest)

Education

Bachelor’s degree in Computer Science or related

Master’s degree preferred

Tools

Docker

Kubernetes

AWS/GCP/Azure

Git/CI tools

PostgreSQL

Redis/MongoDB

Jenkins/GitLab CI/GitHub Actions

Job description

## Senior Python EngineerApply: Hybrid: Mississauga Ontario Canada: Full time: Posted Today: End Date: October 13, 2026 (3 days left to apply): 261000696**Job Description**We are seeking a highly experienced and technically proficient **Senior Python Developer** with 6+ **years of hands-on experience** to design, develop, and deliver critical, scalable, highly available, and performant applications. This role demands deep technical expertise, a strong focus on execution, and a proven ability to deliver robust software solutions, particularly within quantitative and market risk domains.# Key Technical Responsibilities:* Lead hands-on implementation and architecture of Python frameworks for scalable, resilient, and performant applications.* Develop solutions adhering to architectural standards, utilizing in-depth technical and business domain knowledge.* Enforce industry-standard SDLC best practices and contribute to code quality through reviews.* Collaborate with cross-functional teams (Risk, Quants, FO, DevOps, Production Support) for seamless delivery.* Drive development for Stress Testing and Regulatory Risk projects in the Market Risk domain.* Manage project technical aspects, including planning, governance, and taking ownership of initiatives.* Deliver high-quality solutions independently within a globally matrixed environment and under tight deadlines.# Required Technical Qualifications:## I. Core Python & System Development:* **6+ years** of hands-on experience in Application Development, primarily with Python.* **Expert-level Python 3.x proficiency** for scalable, resilient, and high-performance applications.* Advanced knowledge of Python frameworks (FastAPI, Django, Flask), best practices, and design patterns (OOP).* Strong understanding of software architecture principles and distributed system design (Microservices, Event-Driven Architecture).* Extensive experience with relational (PostgreSQL, Oracle, SQL Server) and NoSQL databases (MongoDB, Cassandra, Redis), including advanced SQL.* Proven expertise in designing, developing, and securing RESTful APIs and integration patterns.* Hands-on experience with CI/CD systems (Jenkins, GitLab CI, GitHub Actions, Bitbucket Pipelines) for automated deployment.* Highly experienced with Unix-based operating systems.## II. Cloud & DevOps:* Strong background in cloud platforms (AWS, Azure, GCP), including containerization (Docker) and contributing to Kubernetes orchestration.* Advanced troubleshooting, debugging, and performance optimization for distributed systems.* Proficiency in automated testing frameworks (Pytest, unittest) and TDD methodologies.* Solid understanding of secure coding practices and application security principles (OWASP Top 10).* Expertise in Git (Bitbucket, GitHub) for advanced branching and pull request workflows.## III. Quantitative & Risk Domain:* Experience developing Quantitative/Calc-intensive Python solutions with advanced computation libraries.* Sound understanding and exposure to various Risk Methodologies.* Exposure to mathematical modeling/finance insights.## IV. Artificial Intelligence (AI) Integration (Exposure):* Exposure to AI/ML tools and frameworks (TensorFlow, PyTorch, scikit-learn).* Practical experience with AI tools (Copilot, Devin, Claude/Gemini/GPT) for development workflows.* Experience with Agentic AI tools, including writing Agents and Skills, and contributing to Agentic frameworks.* Understanding and practical application of Generative AI concepts in software development.# Professional Skills:* Deep understanding and practical experience with Agile/Scrum methodologies.* Exceptional ability to manage priorities and tasks effectively.* Strong analytical, logical, systems thinking, and critical analysis skills.* Excellent written and verbal communication for diverse audiences.* Ability to work independently, take ownership, and collaborate effectively in global teams.# Desirable Qualifications:* Polyglot Programming Exposure (e.g., Java).* Big Data Technologies (Apache Spark, Hadoop, Kafka) and data warehousing.* Frontend Development (React, Angular, Vue.js).* Relevant Cloud or Industry Certifications.* Experience with banking domain (pricing, risk), CFA/FRM certification.**Key Focus Areas / Desirable Skills**• **Foundational Models:** *Gemini, OpenAI, Claude, Llama, Local Models*• **Machine Learning:** *PyTorch, TensorFlow, Fine-tuning*• **Frameworks:** *LangChain, LlamaIndex, Hugging Face*• **Retrieval Augmented Generation:** *PostgreSQL, Vector DBs, Advanced Retrieval*• **Orchestration:** *LangGraph, Multi-Agent Systems*• **Development:** *Python, FastAPI, Async Programming*• **Deployment:** *Docker, Production APIs, Monitoring*• **Applied Methodology:** *Prompt Engineering, Workflow Design, GenAI Optimization***Education:*** Bachelor’s degree/University degree or equivalent experience in Computer Science, Engineering, or Technology* Master’s degree preferred 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.*