We are seeking a **Senior Python Developer** to take full ownership and maintain two critical Python\-based derivative valuation systems. You will ensure business continuity, collaborate closely with internal stakeholders, and drive modernization efforts aligned with technology strategy. Join us to contribute your expertise and help shape the future of these essential financial applications. **Responsibilities** * Take end\-to\-end ownership of two Python backend derivative valuation systems to ensure continuous operation for external users * Review existing code, architecture, and integration points to independently understand the systems with limited knowledge transfer materials * Maintain and support applications by resolving incidents and ensuring stability with light SLA\-based support * Collaborate directly with product teams and internal stakeholders to understand requirements and workflows * Serve as the primary technical liaison for queries and issues related to these systems * Perform debugging, security updates, and incident resolution to maintain application stability * Work in an agile environment to deliver incremental solutions and iterate based on business feedback * Propose modernization strategies to align systems with broader technology ecosystem and strategy * Coordinate with supporting engineers to delegate operational tasks effectively * Ensure adherence to security best practices for external\-facing applications * Document system changes and updates to facilitate knowledge transfer and maintenance * Monitor system performance and optimize database queries with SQL Server backend * Analyze complex system issues and provide effective solutions * Support integration points with other internal tools and maintain robust security protocols **Requirements** * Strong Python development experience with 3\+ years working on backend systems involving complex financial or valuation models * Proven experience supporting production\-grade external\-facing applications * Proficiency with SQL Server including querying, debugging, and performance optimization * Experience with Python frameworks such as Flask, Pandas, and NumPy * Ability to reverse\-engineer complex systems and rapidly gain ownership with minimal documentation * Knowledge of application integration and security protocols * Demonstrated ability to collaborate with business clients and translate requirements into technical solutions * Experience working in fast\-paced agile delivery environments * Upper\-Intermediate English language proficiency (B2\) * Self\-motivated with strong analytical and troubleshooting skills * Excellent verbal and written communication skills for client and stakeholder engagement * Experience with incident management and application maintenance * Ability to propose and drive application modernization initiatives * Familiarity with financial domain concepts related to derivatives and valuation models is a plus **Nice to have** * Experience with Azure cloud native development * Knowledge of .NET and C\# programming * Familiarity with lightweight front\-end technologies such as JavaScript frameworks or React * Exposure to application modernization techniques and enterprise technology strategies * Understanding of security best practices for external\-facing systems **We offer** * Career plan and real growth opportunities * Unlimited access to LinkedIn learning solutions * Constant training, mentoring, online corporate courses, eLearning and more * English classes with a certified teacher * Support for employee’s initiatives (Algorithms club, toastmasters, agile club and more) * Enjoyable working environment (Gaming room, napping area, amenities, events, sport teams and more) * Flexible work schedule and dress code * Collaborate in a multicultural environment and share best practices from around the globe * Hired directly by EPAM \& 100% under payroll * Law benefits (IMSS, INFONAVIT, 25% vacation bonus) * Major medical expenses insurance: Life, Major medical expenses with dental \& visual coverage (for the employee and direct family members) * 13 % employee savings fund, capped to the law limit * Grocery coupons * 30 days December bonus * Employee Stock Purchase Plan * 12 vacations days * Official Mexican holidays, plus 5 extra holidays (Maundry Thursday and Friday, November 2nd, December 24th \& 31st) * Monthly non\-taxable amount for the electricity and internet bills EPAM is a leading global provider of digital platform engineering and development services. We are committed to having a positive impact on our customers, our employees, and our communities. We embrace a dynamic and inclusive culture. Here you will collaborate with multi\-national teams, contribute to a myriad of innovative projects that deliver the most creative and cutting\-edge solutions, and have an opportunity to continuously learn and grow. No matter where you are located, you will join a dedicated, creative, and diverse community that will help you discover your fullest potential. *By applying to our role, you are agreeing that your personal data may be used as in set out in EPAM´s Privacy Notice and Policy.*