Principal .NET Developer – Capital Markets

Location: London (Hybrid) | Practice Area: Technology & Engineering | Type: Permanent

Engineer high-performance platforms that drive capital markets innovation

The Role

As a Principal .NET Developer at Capco, you’ll architect and lead the delivery of enterprise-scale platforms for our global capital markets clients. Leveraging modern cloud technologies and a deep understanding of financial products and processes, you’ll deliver scalable, secure, and high-performing applications. You’ll also play a leadership role in mentoring engineering teams and supporting Capco’s broader technical capability.

What You’ll Do

• Design and build enterprise-grade .NET solutions for capital markets platforms

• Implement scalable, event-driven systems using modern cloud-native architectures

• Apply engineering best practices including SOLID principles, TDD, and CI/CD pipelines

• Collaborate with stakeholders and mentor teams to ensure project success

• Lead platform architecture discussions, focusing on secure, maintainable solutions

What We’re Looking For

• Proficiency in C# (7.0/8.0) & .NET with a background in building enterprise systems in capital markets

• Strong understanding of trade lifecycle processes and financial instruments (Options, Derivatives, Rates)

• Experience with SQL Server and/or NoSQL solutions; performance tuning and design

• Expertise in AWS (DocumentDB, EKS, EC2, S3, Aurora, CloudFront, Route 53)

• Experience with caching layers like Redis or Elasticache and scalable API design (REST/GraphQL)

Bonus Points For

• Passion for mentoring and contributing to the wider Capco engineering community

• Experience leading client engagements and supporting RFPs or technical pre-sales

• Familiarity with regulatory and compliance aspects in banking environments

• Knowledge of secure design standards and software development lifecycle best practices

• Strong communication skills to engage with business and technical stakeholders

Why Join Capco

• Deliver high-impact technology solutions for Tier 1 financial institutions

• Work in a collaborative, flat, and entrepreneurial consulting culture

• Access continuous learning, training, and industry certifications

• Be part of a team shaping the future of digital financial services

• Help shape the future of digital transformation across FS & Energy.

Benefits 

We offer a competitive, people-first benefits package designed to support every aspect of your life:

• Core Benefits: Discretionary bonus, competitive pension, health insurance, life insurance and critical illness cover. 

• Mental Health: Easy access to CareFirst, Unmind, Aviva consultations, and in-house first aiders. 

• Family-Friendly: Maternity, adoption, shared parental leave, plus paid leave for sickness, pregnancy loss, fertility treatment, menopause, and bereavement. 

• Family Care: 8 complimentary backup care sessions for emergency childcare or elder care. 

• Holiday Flexibility: 5 weeks of annual leave with the option to buy or sell holiday days based on your needs. 

• Continuous Learning:  Your growth, your way - minimum 40 hours of training annually. Take your pick; workshops, certifications, e-learning. Also, Business Coach assigned from Day One: Get one-on-one guidance to fast-track your goals and accelerate your development. 

• Healthcare Access: Convenient online GP services. 
• Extra Perks: Gympass(Wellhub), travel insurance, Tastecard, season ticket loans, Cycle to Work, and dental insurance.

Inclusion at Capco We’re committed to making our recruitment process accessible and straightforward for everyone. If you need any adjustments at any stage, just let us know – we’ll be happy to help. We value each person’s unique perspective and contribution. At Capco, we believe that being yourself is your greatest strength. Our #BeYourselfAtWork culture encourages individuality and collaboration – a mindset that shapes how we work with clients and each other every day.

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