NET Back-End Developer

We have a proven concept and a solid foundation, now, we need a Mid-level Back-End Developer with strong .NET expertise to join our engineering team and help design, build, and maintain robust, scalable server-side applications and APIs that power our products and services. You will work closely with product managers to translate complex requirements into clean, maintainable, and performant code, solving complex business problems, and collaborating in an agile environment., In this role, you will be a core contributor to our application lifecycle. You will:

• Build & Iterate: Design, develop, and maintain high-quality back-end services, RESTful/GraphQL APIs, and microservices using .NET.
• Storage: Work with relational databases (primarily SQL Server) - design schemas, write efficient queries, and optimise performance.
• Data Access: Implement data access layers using Entity Framework Core.
• Auth: Build and integrate authentication & authorisation mechanisms.
• Collaborate: Work within a loose Agile/Sprint framework, contributing to storyboarding and regular sprint planning meetings, and work closely with front-end developers, QA engineers, and product owners to deliver end-to-end features.
• Code Quality: Implement clean, maintainable, and automated code testing following Clean Architecture principles and current best practices.
• Performance: Identity and resolve performance bottlenecks, security issues, and production incidents.
• Documentation: Help maintain technical documentation for APIs and services (Swagger / OpenAPI).

Do you have experience in xUnit?, You are a mid-level developer who is “hands-on” by nature, you don’t want to sit in architectural meetings all day; you want to build great products.

• .NET Specialist: You have a proven track record of building production-grade APIs and services, with deep knowledge of .NET 8+, C#, and Entity Framework Core.
• Data & Security Focused: You are comfortable designing robust database schemas and implementing secure authentication flows (such as OAuth2 or OpenID Connect) to protect user data.
• Tooling Savvy: You are a confident user of Azure DevOps, including managing work items on Boards and understanding how to support CI/CD pipelines and releases.
• Quality Driven: You take pride in writing clean, testable code. You understand Clean Architecture principles and can identify and resolve performance bottlenecks before they hit production.
• Agile Mindset: You’re comfortable with the iterative nature of a growing product and can thrive in a sprint-based environment., * Experience: Multiple years of commercial experience in back-end development; at least 5 years with .NET C#.
• Core: At least 2-3 years with .NET 6+ / .NET 8+, Entity Framework Core, LINQ, SQL Server, and asynchronous programming.
• Data & Persistence: You are proficient with Entity Framework Core (code-first approach) and have experience managing relational databases (primarily SQL Server) including schema design and query optimisation.
• Architecture & Patterns: You have a firm grasp of Clean Architecture and Domain-Driven Design (DDD). You advocate for decoupled systems using Dependency Injection and modular monolith or microservices patterns.
• Identity & Security: You have hands-on experience implementing JWT, OAuth2, and OpenID Connect, specifically using Azure Entra or Duende IdentityServer to build secure, identity-aware applications.
• DevOps & Tooling: Azure DevOps for task management (Boards) and maintaining CI/CD Pipelines. You understand how to use Docker for containerising services.
• Testing & Quality: You prioritise code reliability by writing unit and integration tests using xUnit, and you utilise FluentValidation to ensure data integrity across your APIs.
• Performance & Monitoring: You know how to profile applications and implement structured logging using Serilog, integrated with Application Insights for real-time monitoring.

Valued Technical Stack

• Complexity: Previous work on high-traffic / consumer-facing apps or apps with complex business logic.
• Cloud: Experience with cloud platforms (Azure preferred - App Services, Functions, Key Vault, Service Bus, Cosmos DB, etc.).
• Platform: Knowledge of orchestration (Kubernetes).
• Messaging: Experience with message brokers (RabbitMQ, Azure Service Bus, Kafka).
• NoSQL: Familiarity with NoSQL databases (Cosmos DB).
• Front-end: Basic understanding of front-end technologies (to better collaborate with UI teams)

Discover OneOcean: OneOcean is a unified brand born from the integration of OneOcean and Ocean Technologies Group. Owned by Lloyd’s Register, an organisation with more than 260 years of trust, integrity and leadership at sea, OneOcean combines the agility and ambition of a fast-moving innovator with the strength and stability of one of the world’s most trusted maritime institutions. At the heart of OneOcean is a portfolio unlike any other in maritime. A comprehensive, integrated portfolio built on years of expertise, trusted by thousands of maritime professionals around the world. Our Mission: Our mission is clear. In the race to zero emissions, our research, advisory and technical expertise and industry-firsts are supporting a safe, sustainable maritime energy transition. Today we are a leading provider of classification and compliance services to the marine and offshore industries, helping our clients design, construct and operate their assets to accepted levels of safety and environmental compliance.

Why Join OneOcean Crew? Legacy & Innovation: We were created more than 260 years ago as the world’s first marine classification society to improve and set standards for the safety of ships. Global Impact: Our digital solutions are relied upon by more than 30,000 vessels, following the acquisition of OneOcean in 2022 and Ocean Technologies Group in 2024. Product Offering: Covering five proven product areas - learning, fleet operations, compliance, voyage planning and performance management - supporting its customers from ship to shore, from training and people operations, to voyage compliance and optimisation., About OneOcean Group Limited

OneOcean is transforming the future of maritime intelligence. Born from the integration of LR OneOcean and Ocean Technologies Group, we unite decades of maritime expertise with cutting-edge digital innovation under one powerful brand. Our comprehensive portfolio spansLearning, Fleet Operations, Compliance, Voyage Planning, and Performance Management- trusted by thousands of maritime professionals worldwide. By connecting ship and shore, people and data, we help organisations operate more safely, efficiently, and sustainably through real-time intelligence and predictive insights. We are part of Lloyd’s Register (LR) a global leader in marine and offshore engineering, technology, and digital solutions. With over260 years of trust, integrity, and leadership at sea, LR supports more than30,000 vessels worldwide. Together, OneOcean and LR combine the agility of innovation with the strength of a world-renowned institution, driving digital transformation and shaping a more connected, sustainable maritime industry.