Role: Senior Developer – Python, AWS & PySpark
Location: London (Hybrid)
About the role
We are looking for a Senior Developer to join a global organization and take ownership of end-to-end technical delivery. You will design, implement and optimize Python and cloud-based solutions using AWS and PySpark. These power data-intensive, regulation-focused applications used around the world. If you love clean code, scalable architecture and meaningful impact, this is your next move. Your code will help clients meet their regulatory obligations.
Key responsibilities
Design and build
· Design scalable, modular Python applications that process complex business and regulatory data sets, built for long-term reuse and evolution.
· Develop secure, efficient AWS solutions that use core services to support highly available data pipelines and transaction workflows.
· Implement optimized PySpark jobs for large-scale data transformations, with efficient resource usage and predictable performance.
· Create and refine PL/SQL procedures and queries that protect data integrity and support regulatory reporting and high-volume operations.
Lead and collaborate
· Work with product owners and business stakeholders to turn regulatory and governance needs into clear technical requirements.
· Review and refine code from the development team, championing Python standards, AWS best practices and database optimization.
· Provide detailed technical estimates and task breakdowns so sprints are planned accurately and timelines are transparent.
· Partner with cloud operations and security teams to validate deployments, monitoring coverage and incident response.
Secure, improve and sustain
· Guide the adoption of secure coding patterns, encryption and access controls across Python services and AWS configurations.
· Analyze production issues, find root causes and deliver durable fixes that reduce repeat incidents and downtime.
· Document architectures, service interactions and data flows in clear design records that support audit and knowledge transfer.
Things to know before you apply
- Work authorization: Cognizant will only consider applicants for this position who are legally authorized to work in Canada without requiring employer sponsorship, now or at any time in the future.
- Accommodations: If you have a disability that requires reasonable accommodation to search for a job opening or submit an application, please email [email protected] with your request and contact information.
- AI in hiring: We use artificial intelligence (AI) tools to help us screen and assess applications more efficiently. Our team performs additional human review and ultimately decides who moves forward in our hiring process.
- Open position: Unless otherwise stated, this job posting is for an open position on our team.
- Language proficiency: We ask that all candidates have basic English proficiency for company-wide communications purposes. For roles based in Quebec, professional English proficiency is required, as you’ll deliver services to and collaborate with stakeholders outside the province who may not speak French.
- Inclusion: Cognizant is an equal opportunity employer. Your application and candidacy will not be considered based on race, color, sex, religion, creed, sexual orientation, gender identity, national origin, disability, genetic information, pregnancy, veteran status or any other characteristic protected by federal, provincial or local laws.
About Cognizant
Cognizant (Nasdaq: CTSH) is an AI Builder and technology services provider, bridging the gap between AI investment and enterprise value by building full-stack AI solutions for our clients. Our deep industry, process and engineering expertise enables us to build an organization’s unique context into technology systems that amplify human potential, drive tangible outcomes and keep global enterprises ahead in a fast-changing world. See how at cognizant.ai or @cognizant.
