5 of 5 Contract API Design Jobs in the South East

Halian Technology are searching for an Interim API Integrations Specialist to join our client's forward-thinking technology team. Our client is a dynamic and rapidly growing energy supplier based in Oxfordshire, committed to driving business success through smart, reliable energy solutions. Our client challenges the existing marketplace with a tech-driven, customer-focused approach and foster a culture … designing cutting-edge integrations, delivering high-quality solutions, and want to work in a company where your expertise is valued and supportedthis is the role for you. Key Responsibilities: Design, develop, and maintain API integrations between internal systems and external SaaS platforms. Collaborate with product, data, and engineering teams to identify integration requirements and deliver robust solutions. Monitor … and troubleshoot integration workflows, ensuring data consistency across platforms. Translate business requirements into technical specifications for system connectivity. Build and maintain API documentation, providing guidance on integration best practices. Ensure all integrations meet compliance, security, and performance standards. Work closely with SaaS vendors and partners to coordinate technical efforts. Key Requirements: Essential: Strong expertise in digital engineering, CMS design More ❯

from home Role Overview A key client of ours in the media space are seeking an experienced Senior Full Stack Web Developer to play a key role in the design, development, and delivery of innovative, high-performance web applications. This position is central to the ongoing evolution of our programmatic and data-driven integration platforms, with a focus on … across multiple environments. This is an opportunity to work in a collaborative, fast-moving environment where technical expertise, creative problem-solving, and continuous improvement are highly valued. Key Accountabilities Design, develop, and maintain scalable and secure software applications aligned with architectural and business objectives. Partner with business, technical, and product leaders to deliver solutions that support the company's … strategic vision. Champion best practices in coding standards, testing, deployment, and DevOps automation. Contribute to a culture of innovation, collaboration, and continuous technical improvement. Key Responsibilities Lead the design and development of dynamic, responsive web applications using React.js , Node.js , and related technologies. Build and optimize PostgreSQL databases, including schema design, complex queries, and performance tuning. Implement and manage More ❯

every year of education • At least 8-10 years of experience with Information Technology Key Responsibilities • Develop and maintain enterprise-scale .NET applications using ASP.NET Core 9.0 and C# • Design and implement RESTful APIs for biogas trading, inventory management, and regulatory reporting • Build complex business logic for RINS credit calculations, LCFS compliance, and carbon credit trading • Work with PostgreSQL … and Microsoft Identity Platform • Develop email workflow systems and automated reporting for regulatory compliance • Create scheduled background jobs using Quartz.NET for data processing and calculations • Integrate with Microsoft Graph API for SharePoint document management via Azure MS Graph • Build real-time features using SignalR for live trading updates • Implement data validation using FluentValidation • Work with Docker and OpenShift for … containerized deployments Required Technical Skills • 5+ years of experience with .NET development (C#, ASP.NET Core) • Strong experience with Entity Framework Core and PostgreSQL • Proficiency in RESTful API design and OpenAPI/Swagger documentation • Experience with authentication systems (OAuth2, JWT, Azure AD) • Knowledge of containerization (Docker) and Kubernetes/OpenShift • Experience with background job processing and scheduled tasks • Understanding More ❯

and Spring Boot experience, solid understanding of Kubernetes and AWS services, and hands-on database development with SQL-based systems. Familiarity with mobile integrations (iOS/Android native), RESTful API design, and Agile delivery methodologies will be highly beneficial. This is an exciting opportunity to work in a dynamic FinTech environment where innovation, quality, and performance are at More ❯

This is initially a 6 month contract with the potential to extend and will be a hybrid role that will be based in either London or Coventry . Responsibilities: Design robust integration solutions across commercial, HR, and data platforms within a complex, multi-brand retail environment Lead architectural planning for the decommissioning of legacy systems, ensuring smooth transitions to … modern, scalable services Define and document integration standards, including API strategies, event schemas, and interface contracts to enable decoupled, reusable services Implement event-driven architectures using Kafka to support real-time data exchange and responsive system interactions Collaborate cross-functionally with product managers, engineering teams, and platform leads to define scalable service boundaries and integration touchpoints Support the design … adoption of strategic data services, promoting data integrity, consistency, and standardisation across the enterprise Ensure integration consistency in areas such as data handling, authentication, error management, and versioning Lead design reviews for integration solutions, ensuring alignment with enterprise architecture principles and governance frameworks Act as a trusted advisor, championing best practices in integration architecture and guiding teams on modern More ❯