2 jobs found

C# Senior Software Developer - Onsite My client is seeking a talented C# Senior Software Developer to join their Preston-based team. This role offers an exciting opportunity to lead projects, mentor junior developers, and work on high-impact, secure banking solutions. You will be a key contributor to web portal and API development, ensuring performance, security, and reliability in a dynamic environment. This role is ideal for developers with strong technical expertise who are looking to grow into leadership or team management responsibilities. Key Responsibilities Develop and maintain web portals using ASP.NET MVC / .NET Core Design and integrate REST APIs with internal and third-party services Implement secure authentication mechanisms (JWT, OAuth2, API Keys) Connect applications to relational databases using Entity Framework Core (DbContext, LINQ, Migrations) Debug and trace request flows from UI Controller API Database Response Maintain and publish API documentation via Swagger / OpenAPI Ensure API security, reliability, and performance (error handling, retry logic, logging, timeouts, CORS) Collaborate with database, infrastructure, and QA teams for portal and API releases Participate in code reviews, version control, and CI/CD deployment workflows Required Technical Skills C# (strong proficiency) ASP.NET MVC or .NET Core Web API MVC concepts: Routing, Controllers, Filters, Middleware, Model Binding, Dependency Injection Entity Framework Core (DbContext, DbSet, OnModelCreating, LINQ) and ADO.NET/Raw SQL experience MS SQL Server or MySQL database experience HTML5, CSS3, JavaScript REST API expertise and integration (HttpClient, RestSharp, JSON serialization/deserialization, CORS, HTTPS, API security) Git version control and CI/CD workflows (Azure DevOps, GitLab CI preferred) Hosting experience with IIS or Kestrel Docker basics (preferred but not mandatory) Preferred/Bonus Skills Experience with fintech or payments API integration Cloud services (Azure, AWS) hosting basics Webhooks and event-based APIs Structured logging tools (Splunk, ELK, App Insights) Performance optimization and API rate-handling Why Join My Client Be part of a pioneering fintech/secure banking technology company Opportunity to mentor and lead junior developers Work in a supportive, collaborative, and technically driven environment Gain experience in high-security, mission-critical software projects Interested? Please Click Apply Now! C# Senior Software Developer

Senior Software Engineer / Developer (Data) London / WFH to £115k Global-leading FinTech is seeking a Senior Software Engineer to take ownership of a new team responsible for data focussed strategic enhancements on their core platform. The organisation is a pioneer in the field of cross-asset securities and derivatives post-trade processing technology and have created ground-breaking, adaptable software that produces secure and scalable solutions for peak operational efficiency and optimum business performance for their clients. This is a great opportunity to accelerate your career alongside established business and technology leaders and deepen your finance experience. As a Senior Software Engineer, you'll work on strategic initiatives to develop integration and data migration strategies and tools to allow highly automated migration or integration between the PTP (Post Trade Processing) platform and legacy internal and external systems. You'll be working on Greenfield systems, using a range of technology, you will be granted a great deal of autonomy across the full development lifecycle, influencing key technical decisions and will have the opportunity to grow the team and move into a leadership role if desired. Location / WFH: You'll join colleagues in the London office three days a week with flexibility to work from home the other two days. About you: You're a data centric, Senior Software Engineer with a strong knowledge of modern software engineering best practices You have strong development experience with C#, C++ or Python You have advanced SQL database knowledge (they use Oracle), experience with data transformation technologies such as Databricks or Snowflake and data streaming technologies such as Kafka You have a good understanding of financial markets and the trade lifecycle You're keen to take ownership and enjoy working proactively with minimal supervision You have excellent collaboration and stakeholder management skills You're degree educated in a STEM discipline What's in it for you: As a Senior Software Engineer / Developer (Data) you will receive a competitive package: Salary to £115k Pension (to 9% contribution) Healthcare Volunteer / charity days Hybrid working Career development and training Apply now to find out more about this Senior Software Engineer / Developer (Data) opportunity. At Client Server we believe in a diverse workplace that allows people to play to their strengths and continually learn. We're an equal opportunities employer whose people come from all walks of life and will never discriminate based on race, colour, religion, sex, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status. The clients we work with share our values.