11 of 11 Contract API Design Jobs in London

Fullstack Engineer (Backend)

Hiring Organisation
Randstad Technologies Recruitment
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
£450 - £550/day
Opportunity You will join a high-impact development squad building commercial offerings on top of the thriving open-source Backstage framework. You will design and build backend systems, APIs, and developer portals that elevate the developer experience across external commercial clients and internal engineering teams alike. Your Impact Backend … API Systems: Design, build, and maintain scalable backend services and APIs primarily using TypeScript, Node.js, and modern web technologies. Developer Experience & Infrastructure: Build and operate infrastructure, developer toolsets, and CI/CD deployment pipelines to streamline engineering workflows. Engineering Excellence: Elevate code quality through technical RFCs, code reviews ...

Senior Full Stack Developer (React, JavaScript & C#.NET)

Hiring Organisation
Pontoon
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£650 per day
Python (pyspark): Experience with data pipelines and analytics is a plus. Power BI: Familiarity with developing dashboards and data models. Architecture: Knowledge of microservices, API design, and event-driven architectures. DevOps/CI/CD: Experience with Azure DevOps, GitLab, GitHub Actions, or similar tools. Cloud Platforms: Proficient … Azure or AWS (Azure preferred). Databases: Strong skills in SQL Server, PostgreSQL, or other relational databases. Key Responsibilities Design & Develop: Create and maintain full stack applications using React JS and C#.NET Core. Build Services: Develop high-performance backend services and RESTful APIs with a focus on scalability ...

Backend Engineer

Hiring Organisation
Robert Half Limited
Location
London, United Kingdom
Employment Type
Contract, Work From Home
systems that enable global commerce, while evolving an existing real-time platform to support new markets. You will address backend capacity constraints and help design a shared transaction and ledger layer used across multiple business lines. This is a hands-on senior engineering role requiring both high-quality delivery … strong technical leadership in ambiguous, high-scale environments. You will be expected to: Design scalable systems with correctness and failure modes considered from the outset Clarify and scope requirements before proposing solutions Make pragmatic trade-offs in system design, avoiding over-engineering Operate independently without reliance ...

Senior C# Engineer .NET 9, AWS Lambda, SQS, SNS Outside IR35

Hiring Organisation
Smart Sourcer Limited
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
From £700 to £800 per day
Overview: Youll operate as the technical spearhead for a greenfield product build, reporting to the Director of Engineering. Expect deep backend engineering, distributed system design, and high-quality serverless delivery, plus the chance to adopt modern AI-assisted development practices as part of your workflow. What Youll Bring: Senior … ability to architect and lead distributed REST microservices at scale. Strong authority in AWS serverless engineering: Lambda-first mindset, hands-on experience with API Gateway, SQS, Step Functions, EventBridge and IAM. Deep data expertise across Aurora MySQL and DynamoDB: schema design, access patterns, indexing, query tuning, and pragmatic ...

Golang Technical Lead

Hiring Organisation
Gazelle Global Consulting Ltd
Location
City of London, London, United Kingdom
Employment Type
Contract
Join a high-profile transformation programme as a Technical Lead, taking ownership of the design, development and delivery of enterprise-scale cloud-native applications. This is an excellent opportunity to combine hands-on engineering with technical leadership, working across Agile teams to deliver scalable, resilient solutions. Excellent Day Rate … working closely with architects and business stakeholders to deliver modern cloud-native platforms. Key Skills Golang development Microservices architecture Azure Cloud Distributed Systems REST API design Document Databases & NoSQL Solution architecture and technical governance Agile technical leadership Kubernetes (AKS) CI/CD and DevOps practices For more information ...

Contract AI Software Engineer - DV Cleared

Hiring Organisation
Searchability NS&D
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£450 - £650 per day
Experience with AWS or Azure Familiarity with Docker and Kubernetes Experience working in secure or highly regulated environments Strong understanding of software architecture and API design IT WOULD BE NICE FOR THE AI SOFTWARE ENGINEER TO HAVE.... Experience with RAG pipelines and vector databases Knowledge of MLOps tooling ...

Contract AI Software Engineer - DV Cleared

Hiring Organisation
NSD
Location
City of London, London, United Kingdom
Employment Type
Contract, Work From Home
Contract Rate
£450 - £650 per day
Experience with AWS or Azure Familiarity with Docker and Kubernetes Experience working in secure or highly regulated environments Strong understanding of software architecture and API design IT WOULD BE NICE FOR THE AI SOFTWARE ENGINEER TO HAVE. Experience with RAG pipelines and vector databases Knowledge of MLOps tooling ...

Net Developer

Hiring Organisation
Pontoon
Location
Bromley, London, United Kingdom
Employment Type
Contract
Contract Rate
£700 - £750/day
Develop and maintain high-quality software applications using .NET (4.5+/.NET Core) and Python. Collaborate with cross-functional teams to gather requirements and design effective solutions. Provide support to team members and stakeholders to ensure smooth project execution. Liaise with technical and business colleagues to understand functional requirements … deliver solutions that align with business objectives. Utilise your understanding of Web Services (REST, SOAP) to design and document APIs effectively. Work with MS SQL Server, including TSQL, SSIS, SSRS for database management and reporting. Utilise version control tools such as Git/Bitbucket and job scheduling tools like ...

.Net Developer

Hiring Organisation
Pontoon
Location
Bromley, Kent, England, United Kingdom
Employment Type
Contractor
Contract Rate
£700 - £750 per day
Develop and maintain high-quality software applications using .NET (4.5+/.NET Core) and Python. Collaborate with cross-functional teams to gather requirements and design effective solutions. Provide support to team members and stakeholders to ensure smooth project execution. Liaise with technical and business colleagues to understand functional requirements … deliver solutions that align with business objectives. Utilise your understanding of Web Services (REST, SOAP) to design and document APIs effectively. Work with MS SQL Server, including TSQL, SSIS, SSRS for database management and reporting. Utilise version control tools such as Git/Bitbucket and job scheduling tools like ...

S/4HANA - Coupa Integration Architect

Hiring Organisation
CBSbutler Holdings Limited
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
Up to £558 per day + inside ir35
between Coupa and SAP S/4HANA. This is an opportunity to work on a high-profile global programme, owning integration architecture from initial design through to deployment, cutover and Hypercare. What you'll be doing: Designing and delivering Coupa SAP S/4HANA integrations across complex enterprise landscapes … Leading integration architecture, solution design and technical delivery Building and managing APIs including REST/JSON, OData, IDocs and BAPIs Supporting procurement process integrations covering: Supplier and Business Partner data Purchase Orders Goods Receipts Service Entry Sheets Invoices and payment status updates Master data synchronisation Working with integration platforms ...

Solution Architect - Integration - Salesforce

Hiring Organisation
SR2
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
£650 - £750/day
drive architectural decisions will be essential. Responsibilities Define and maintain the end-to-end solution architecture across the rewards portal and wider Salesforce ecosystem. Design integration patterns across Salesforce, customer identity, APIs, mobile applications and enterprise platforms. Translate business and technical requirements into scalable, resilient and maintainable solution designs. … Define the architecture for SSO, customer identity integration and associated authentication journeys. Review and assure API designs, data flows, integration components and system dependencies. Support the design of mobile and in-app webview customer experiences. Produce architecture artefacts, solution options, design decisions and technical roadmaps. Coordinate suppliers ...