6 senior api developer jobs found

Senior AI Engineer | £600/day Outside IR35 | 6-Month Contract Industry: Technology / Capital Markets Location: London - 3 days in office Job Type: Contract Our client, a forward-thinking technology organisation, is seeking a Senior AI Engineer to join a team building production-grade AI systems powered by large language models (LLMs). You will work closely with software engineers and product stakeholders to design, develop, and deploy scalable AI applications, focusing on multi-agent orchestration, intelligent tool integration, and reliable production workflows. Responsibilities Design and implement LLM-powered AI systems, including RAG pipelines, vector/knowledge databases, and agentic frameworks. Build and maintain production-grade AI applications with clean code, APIs, data pipelines, and robust error handling. Develop and maintain evaluation frameworks to measure and monitor system performance, accuracy, and reliability. Implement feedback loops...

Contract Java Developer – Data Up to £700 per day Outside IR35 (6 month rolling) In office – City of London Quant Capital is hiring for a small, high-performing market maker in London. This is a junior-to-mid role focused primarily on Java development, with a secondary responsibility owning straightforward Python ETL/data ingestion into AWS and PostgreSQL. This is a growing team focused on data ingestion and building tooling for the wider firm. What you’ll do: Build and enhance Java backend services (APIs, batch jobs, integrations) used across the business Write clean, testable code with solid engineering discipline (testing, code review, debugging, production support) Maintain and extend Python-based ingestion/ETL (pragmatic plumbing, not heavy data engineering) Work with PostgreSQL (schemas, migrations, performant queries, data validation) Improve service reliability: monitoring/logging, sensible alerting, and predictable deployments via CI/CD Tech:...

IT Applications Manager - Central London £650 - £700 p/d (outside IR35) - 3 month initial term Well-established and highly profitable construction engineering business is seeking an experienced IT Applications Manager to join them on a permanent basis. This is a critical leadership role within an organisation undergoing significant digital transformation, with ambitious growth and acquisition plans driving demand for scalable, standardised and efficient business applications. Reporting into the Head of IT, you will lead the delivery, governance and optimisation of business applications across the enterprise. This role blends strategic oversight, hands-on expertise with modern low-code/no-code platforms and direct leadership of a multidisciplinary applications team. The IT Applications Manager will oversee a suite of core enterprise systems, including but not limited to: Workday, UKG (Kronos), COINS, SharePoint, Snowflake, Autodesk Construction Cloud, Pro-Sapien, Primavera P6...

Contract Java Developer – Data Up to £700 per day Outside IR35 (6 month rolling) In office – City of London Quant Capital is hiring for a small, high-performing market maker in London. This is a junior-to-mid role focused primarily on Java development, with a secondary responsibility owning straightforward Python ETL/data ingestion into AWS and PostgreSQL. This is a growing team focused on data ingestion and building tooling for the wider firm. What you’ll do: Build and enhance Java backend services (APIs, batch jobs, integrations) used across the business Write clean, testable code with solid engineering discipline (testing, code review, debugging, production support) Maintain and extend Python-based ingestion/ETL (pragmatic plumbing, not heavy data engineering) Work with PostgreSQL (schemas, migrations, performant queries, data validation) Improve service reliability: monitoring/logging, sensible alerting, and predictable deployments via CI/CD Tech:...

Java Developer - SC Cleared Location: London (1-2 days onsite per month) Contract: Outside IR35 Rate: £600-£675 per day Duration: 12 Month Contract Start: Immediate/Short Notice Preferred Eligibility: Active SC Clearance required (DV clearance ideally) Overview An experienced Java Developer is required to build and maintain scalable, high-performance applications within a secure public sector environment. Requirements Strong experience with Java & Springboot Solid Java Back End development experience Experience working in public sector Strong understanding of API integration and system design Active SC Clearance required (DV clearance ideally)

Full Stack Developer (React/TypeScript/Java) Location: London (1-2 days onsite per month) Contract: Outside IR35 Rate: £650-£700 per day Duration: 12 Month Contract Start: Immediate/Short Notice Preferred Eligibility: Active SC Clearance required (DV clearance ideally) Overview An experienced Full Stack Developer is required to build and maintain scalable, high-performance applications within a secure public sector environment. The role requires a 50/50 split across Front End and Back End development . Requirements Strong experience with React and TypeScript Solid Java Back End development experience Experience working in a full stack capacity (approx. 50/50 Front End/Back End) Strong understanding of API integration and system design Active SC Clearance required (DV clearance ideally)