26 to 50 of 60 API Design Jobs in London

Senior Golang/Java Security Engineer

Hiring Organisation
Atrium Workforce Solutions Ltd
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£600 - £650 per day
vulnerability types SAST, SCA, and DAST, including the strengths and weaknesses of each At least one major cloud provider (e.g. AWS, GCP, Azure) REST API design HTTP Authentication Linux at the terminal, including scripting and automation (e.g. shell, Python) Some other highly valued skills may include: Experience with ...

Senior Backend Engineer

Hiring Organisation
THE IDOLS GROUP LIMITED
Location
London, United Kingdom
Employment Type
Permanent
systems problems. Skills and experience Strong expertise in Python and modern backend frameworks Deep knowledge of relational databases, particularly PostgreSQL Strong understanding of RESTful API design and microservices patterns Experience working with cloud platforms and containerised environments (Docker, Kubernetes) Experience with CI/CD pipelines, automated testing ...

Senior Salesforce Developer

Hiring Organisation
Salt Search
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
Salary negotiable
telco, working fully remote from Hungary. Blend of hands-on Salesforce engineering, integrations, and AI-driven solutions in an Agile (Scrum) environment. Key responsibilities Design and develop high-quality solutions on Salesforce Service Cloud and Sales Cloud based on business requirements. Contribute actively to the customer's Salesforce development … community, sharing best practices and patterns. Build, enhance, and maintain Lightning components, Apex classes/triggers, flows, and complex configuration. Design and implement integrations with various internal and external systems, with and without middleware, following Force.com API best practices and integration patterns. Support the design and development ...

(Senior) Full Stack Engineer

Hiring Organisation
BioTalent
Location
City of London, London, United Kingdom
with potential leadership options A high-autonomy role within a technically rigorous environment Your Responsibilities Own and evolve the React and Next.js application architecture Design and implement scalable UI patterns for complex workflows and data visualisation Define state management strategies for long-running jobs and asynchronous systems Build clean … years of experience building production React applications - React, Next.js, TypeScript Experience deploying and managing applications on AWS using Infrastructure as Code and containerized workflows API Design experience UX/UI & Design systems Experience with state management at scale (e.g. React Query, Zustand, Recoil) Knowledge of authentication, authorisation ...

Senior Backend Developer (.NET | AI-First SaaS Platform)

Hiring Organisation
Keepnet
Location
London, UK
Employment Type
Full-time
that power these systems, working in a multinational, AI-first engineering team where quality, ownership, and long-term thinking matter. What You'll Do Design, build, and maintain scalable backend services for Keepnet's Human Risk Management platform. Build clean, modular APIs that integrate internal services and third-party … enable automation, reporting, and security workflows. Develop testable, maintainable codebases using principles such as Clean Architecture, DDD, and TDD. Own the full development lifecycle: design, implementation, CI/CD (Azure), and post-release monitoring. Work on distributed and asynchronous systems using message queues, background workers, and event-driven workflows. ...

Application Security Engineer

Hiring Organisation
Atrium Global
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
From £550 to £650 per day
strengths and weaknesses of each At least one programming language (e.g. Java, Go) At least one major cloud provider (e.g. AWS, GCP, Azure) REST API design HTTP Authentication Linux at the terminal, including scripting and automation (e.g. shell, Python) Some other highly valued skills may include: Experience with ...

AppSec Engineer / Application Security Engineer

Hiring Organisation
Atrium Workforce Solutions Ltd
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£550 - £650 per day
strengths and weaknesses of each At least one programming language (e.g. Java, Go) At least one major cloud provider (e.g. AWS, GCP, Azure) REST API design HTTP Authentication Linux at the terminal, including scripting and automation (e.g. shell, Python) Some other highly valued skills may include: Experience with ...

Junior Back-end Engineer

Hiring Organisation
ivee
Location
London Area, United Kingdom
maintain server-side logic using modern backend frameworks (e.g. Node.js, Python, Go) Work with APIs — designing, integrating, and maintaining RESTful endpoints Support database design and optimisation (e.g. PostgreSQL, MongoDB) Collaborate with front-end and product teams to deliver full-stack features Write clean, testable, and maintainable code Help improve ...

Technical Architect

Hiring Organisation
Sphere Digital Recruitment
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£80,000 - £90,000 per annum
office Technical Architect About the role This is a rare opportunity to join a government-backed initiative at a very early stage, helping to design and deliver a new digital platform that enables transparent licensing and ethical access to high-quality digital content at scale. We are assembling … that the platform is secure, intuitive, and reliable for all users. This is a hands-on architecture role focused on system design and technical delivery rather than business development or account management. The role also plays a key part in shaping the future technical service offering by applying lessons ...

Senior Scala Developer

Hiring Organisation
SF Recruitment
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£60,000 - £90,000 per annum
following key skills: - At least 4 years commercial Scala programming - Strong framework experience (Akka, Play etc) - Relational database experience - PostgreSQL - MongoDB, NoSQL - RESTful API design and integration experience - Solid unit test understanding - Spec2, scalaTest etc - Experience working in a TDD/BDD driven environment - Containerization experience - Docker, Kubernetes … well-established friendly team then please apply now to be considered and for further details. Senior Scala Developer Up to £90,000 Scala, REST Api, NoSQL, TDD/BDD, functional programming, CI/CD, Play, Akka ...

Founding Engineer (Full Stack / Backend)

Hiring Organisation
Affinity Labs
Location
London Area, United Kingdom
early-stage, hands-on role with significant autonomy and responsibility to drive backend product development, collaborating closely with founders, creators, and product/design to turn lean specs into reliable, scalable services. Responsibilities Implement features end-to-end on the backend (APIs → data models → integrations) and maintain quality while … z2bz0 years building production backends/services , with shipped work and clear ownership. Strong Python (FastAPI) and database skills ( PostgreSQL/MongoDB ); solid API design fundamentals. Familiarity with AWS serverless patterns and Docker for bespoke services; basic CI/CD concepts. Comfortable with Redis (caching/sessions ...

Senior Backend Engineer (TypeScript/Ruby)

Hiring Organisation
Oliver Bernard
Location
City of London, London, United Kingdom
experiences at scale. Package 💷 £70–90k + 5% bonus 🏢 Hybrid (2 days onsite, London) What you’ll do Own the full lifecycle of services: API design, architecture, deployment, and production Build an internal platform delivering consistent, real-time communications across multiple digital touchpoints Collaborate with Product, Data, Marketing ...

Site Reliability Engineer

Hiring Organisation
McGregor Boyall
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£90,000 - £95,000 per annum
SLOs, and participating in support rotas. Coding/scripting experience (Python/Bash) in a commercial setting. Database knowledge, streaming and batch operations, and API design. Good background with Kubernetes (ideally microservice architectures using Istio service mesh). Extensive experience with cloud-native solutions (ideally Google Cloud). Solid ...

Senior Software Engineer

Hiring Organisation
Stott and May
Location
London Area, United Kingdom
onsite) Salary: Up to £80k DOE Type: Perm Job Description We are looking for a passionate Senior Java Engineer in London to lead the design and development of core product features and services that power an app used by thousands of travellers on a daily basis. As a Senior … impactful product features Ensure the quality of the features you built, follow-up on usage/issues post release. Work closely with product and design team to deliver new features that align with the needs of the business Provide technical leadership and mentoring to other engineers on the team ...

Salesforce &/ React Native Developer

Hiring Organisation
Atrium Workforce Solutions Ltd
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£500 - £550 per day
IR35) Sector: Banking Key Skills & Experience Salesforce +5 years experience AND/OR React Native (Web) +5 years Java +5 years TDD, BDD RESTful API design & build OAS/YAML Unit Testing GitLab CI/CD Pipelines Agile practitioner, SonarQube, Veracode, Jira, Confluence Banking/Financial services background ...

C# Developer

Hiring Organisation
VIQU IT
Location
City, London, United Kingdom
Employment Type
Contract
Contract Rate
GBP 300 - 350 Daily
Developer: Must have a strong background in C#/.NET development. Experience of PostgresSQL or other SQL databases. CI/CD experience. Experience in API design and building system integrations. Microsoft Dynamics integration (highly desirable). Python and/or JavaScript experience (desirable). Excellent communication skills ...

C# Developer

Hiring Organisation
VIQU IT
Location
London, Coleman Street, United Kingdom
Employment Type
Contract
Contract Rate
£300 - £350/day
Developer: Must have a strong background in C#/.NET development. Experience of PostgresSQL or other SQL databases. CI/CD experience. Experience in API design and building system integrations. Microsoft Dynamics integration (highly desirable). Python and/or JavaScript experience (desirable). Excellent communication skills ...

AI Engineer

Hiring Organisation
Tenth Revolution Group
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
£250 - £300/day
similarity matching - Context window management and chunking strategies MCP & Tool Integration: - Model Context Protocol (MCP) implementation - Tool calling and function integration with LLMs - API design for LLM tool interfaces - AWS Lambda integration with agents AI Safety & Evaluation: - Guardrail implementation (hallucination detection, toxicity filtering) - Response evaluation framework design ...

AI Engineer

Hiring Organisation
Tenth Revolution Group
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£250 - £300 per day
similarity matching- Context window management and chunking strategies MCP & Tool Integration:- Model Context Protocol (MCP) implementation- Tool calling and function integration with LLMs- API design for LLM tool interfaces- AWS Lambda integration with agents AI Safety & Evaluation:- Guardrail implementation (hallucination detection, toxicity filtering)- Response evaluation framework design ...

Senior Software Engineer

Hiring Organisation
ZEREN
Location
Greater London, England, United Kingdom
founding team Build technology that fundamentally changes how teams use data What We Are Looking For Strong experience building in Python Deep understanding of design patterns and system architecture Experience building scalable, performant platforms Strong grasp of event-driven systems and concurrency Solid database and API design … Have Zero-to-one product experience, including OSS or side projects Data engineering experience such as pipelines and analytics Experience integrating LLMs, including prompt design and understanding model capabilities Deeper cloud experience, especially with GCP Experience with Encore, though this is easy to pick up Ways of Working Ownership ...

Senior Software Engineer

Hiring Organisation
Formula Recruitment
Location
City of London, London, United Kingdom
maintainable code. This is an exciting opportunity to join collaborative and innovative startup with opportunities for professional growth and learning. What You’ll Do Design and develop high-throughput, low-latency APIs using Typescript/Node.js. Build and maintain real-time data ingestion and processing pipelines. Optimise backend services … delivery. Collaborate with front-end teams to power trading consoles and dashboards. Profile and tune Node.js applications for performance and memory efficiency. Ensure secure API design and compliance with data privacy regulations. Contribute to architecture discussions, code reviews, and documentation. Key requirements Strong experience with Node.js in production ...

React Frontend UI Developer - Fixed Income & Credit Trading

Hiring Organisation
Vertus Partners
Location
London, United Kingdom
Employment Type
Permanent
Salary
GBP 75,000 - 100,000 Annual
modern, responsive trading tools, working closely with traders, quants, and Back End engineers to support Real Time decision-making and risk management. Key Responsibilities: Design and develop scalable UI applications for Fixed Income and credit trading desks Build Real Time, data-heavy interfaces using modern Front End technologies Partner … with traders to translate trading workflows into intuitive user experiences Collaborate with Back End teams on API design and performance optimisation Contribute to architectural decisions and UI standards across the platform Required Skills & Experience: Strong commercial experience with TypeScript, React, and modern JavaScript Proven background building data-intensive ...

Security Engineer

Hiring Organisation
Red - Specialist Recruitment
Location
EC3V, Langbourn, Greater London, United Kingdom
Employment Type
Permanent
security expertise to projects built on multiple platforms, such as Salesforce and Azure Exposure to Cloud Native software development, including cloud infrastructure and API design (Azure preferred) Proven experience applying modern standards such as OWASP CI/CD, DSOMM, SAMM etc Strong networking protocol knowledge (TCP/… HTTP/3, AMQP, streaming protocols etc), cloud network design (VPNs, subnets, regions/zones etc), and integration related technologies (Auth0, APIM) Expertise with SAST & SCA systems such as Snyk, Checkmarx Experience with DAST systems such as OpenZAP, Qualys DAST (preferred) ideally with HTTP APIs Ability to manage large ...

Senior Test Engineering Manager Automation-First

Hiring Organisation
Salt Search
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
£480 - £500 per day
automated testing into CI/CD pipelines so quality is continuous and enforced Upskill and mentor test engineers and software engineers in automation, test design, and quality engineering Establish quality standards, best practices, and governance without slowing teams down Reduce manual testing, flaky automation, and release risk Partner with … engineering leadership to raise overall engineering maturity Influence system and API design to improve testability, resilience, and maintainability Essential experience A software engineer at heart with senior test engineering leadership experience Proven track record of creating and evolving test strategies, not just executing them Experience building and scaling ...

Technical Data Architect

Hiring Organisation
Harnham - Data & Analytics Recruitment
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£80,000 - £95,000 per annum
digital content platform, shaping cloud infrastructure, data models, integrations, APIs and security across the solution. You'll work closely with the platform provider to design and govern a scalable architecture built on modern cloud services such as AWS, Azure or GCP, ensuring reliability, performance and compliance. A key responsibility … schemas and metadata structures, partnering with Solutions Architects to ensure all onboarding aligns with industry best practices. You'll champion best-practice patterns across API design, integration layers, authentication, data pipelines and cloud-native services, with hands-on involvement in troubleshooting and implementation support. The role also produces ...