26 to 50 of 56 API Design Jobs in London

Lead Java Modernization Engineer - London, Wembley

Hiring Organisation
Adecco
Location
London, United Kingdom
Employment Type
Permanent
Salary
£75000 - £80000/annum + Benefits
just familiarity, but production ownership. Azure Integration: Proven experience building applications that consume Azure-native services, including Azure Key Vault for secrets, Azure Storage API, and Azure Service Bus for event-driven messaging. DevOps Mindset: Solid understanding of the full CI/CD lifecycle; comfortable reading and contributing … Dockerfiles and GitHub Actions YAML workflows - not as a DevOps engineer, but as a developer who understands the pipeline their code flows through. API Mastery: Deep expertise in RESTful API design principles, OAuth2 authentication flows (including FusionAuth integration), and DMARC-compliant transactional email logic via SendGrid. Duties ...

Integration Developer FTC

Hiring Organisation
itecopeople
Location
London, United Kingdom
Employment Type
Permanent, Work From Home
Salary
£60,000
using modern cloud-native and streaming technologies. Key Responsibilities Develop event-driven integrations and backend services Build connectors, event-processing services, and data pipelines Design scalable integration patterns, schemas, and event flows Develop CDC pipelines and resilient messaging solutions Improve observability through logging, metrics, and tracing Deploy containerised services … Grafana Required Skills Strong software engineering background Experience building integration or event-driven platforms Kafka, Redpanda, or similar streaming technologies Enterprise system integrations and API design Agile development experience Strong communication and collaboration skills Desirable Skills Go and/or Python CDC pipeline development Azure cloud experience Observability ...

AI Platform/ DevOps Engineer

Hiring Organisation
The Portfolio Group
Location
City of London, London, Castle Baynard, United Kingdom
Employment Type
Permanent
Salary
£70000 - £80000/annum + Benefits
secure, and cost-efficient platform infrastructure that enables AI engineering teams to ship and operate AI products reliably in production. What you'll do Design, build, and operate cloud-native AI platform infrastructure across AWS (Lambda, API Gateway, DynamoDB, S3, CloudWatch) and Databricks Deploy and operate containerised services … workflows, and RAG components Implement observability across AI workloads using CloudWatch, MLflow, and OpenTelemetry - covering latency, throughput, cost, and system health Apply secure-by-design principles including IAM, encryption, network controls, and audit logging Work closely with AI engineers to translate prototypes and proof-of-concepts into production-ready ...

Senior C# Engineer - Agentic Engineering, .NET 9, AWS Lamba & SQS

Hiring Organisation
Smart Sourcer Limited
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
From £750 to £800 per day
with the ability to architect and lead distributed REST microservices at scale. Strong authority in AWS serverless : Lambda-first, with hands-on experience across API Gateway, SQS, Step Functions, EventBridge and IAM. Practical experience with Claude Code (or similar) and advanced agentic workflows multi-agent orchestration, context management, custom … commands/skills, and scaling AI-assisted delivery. Deep data expertise across Aurora MySQL and DynamoDB schema design, access patterns, indexing, query tuning, and pragmatic trade-offs around consistency, scale and cost. Proven ability to design event-driven systems with SQS: idempotency, retries, ordering, DLQs and operational robustness. ...

Engineering Lead, Scale

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
foundational systems that power our embedded finance platform at global scale. The team owns multi‐tenant infrastructure, drives cross‐domain product capabilities, and helps design technical solutions for enterprise customers. Key areas of ownership include: Embedded Finance Platform: Build and maintain the infrastructure powering customers like Rippling, Navan, Qantas … career development. Set technical direction for scalable, reliable backend systems and partner with senior engineers on architecture and design. Ensure high standards for system design, code quality, testing, and operational excellence. Drive improvements across reliability, observability, security, and developer productivity. Work cross‐functionally with product, design, compliance, sales ...

Full Stack Developer

Hiring Organisation
Robert Half
Location
London, South East, England, United Kingdom
Employment Type
Contractor
Contract Rate
Salary negotiable
this is an opportunity to help shape the future of a rapidly evolving platform. Role The Full Stack Developer will contribute to full-stack design and development across the platform. Design, develop, and maintain both front-end user interfaces and back-end services, APIs, and databases. Monitor platform … strong focus on backend development. Bachelor's or Master's degree in Computer Science, Engineering, or a related discipline. Strong understanding of database design, data modelling, and optimisation, particularly using SQL. Hands-on experience working with Google Cloud Platform (GCP) services. Experience monitoring production systems, triaging issues, and distinguishing ...

Manager - Lead AI Engineer

Hiring Organisation
Anson Mccade
Location
City of London, London, United Kingdom
Employment Type
Permanent, Work From Home
Salary
£70,000
building and knowledge-sharing initiatives Skills & Experience Required Significant senior backend development experience with strong Python proficiency (async programming, concurrency, multithreading) Expertise in RESTful API design, OpenAPI/Swagger documentation and API lifecycle best practices Hands-on experience with ML libraries: PyTorch, PySpark, scikit-learn, Hugging Face … machine learning, cloud computing or data engineering highly advantageous Professional accounting qualification desirable but not required Nice to Have Experience with Microsoft Graph API Background in audit, financial services or regulated industry technology What's on Offer A competitive salary and benefits package, flexible hybrid working across 20+ ...

Software Engineer C#, React, .NET

Hiring Organisation
RX Global
Location
Greater London, United Kingdom
Employment Type
Full Time
.NET/C#,, NET Core and familiarity with SQL or data skills Proficiency in Front end tech stack React or Angular Understanding of system design, domain modelling, and API design principles Experience writing unit and integration tests and working with CI/CD pipelines Exposure to cloud ...

Director, Forward Deployed Engineering

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
lead a team of elite engineers who embed directly with Fortune 500 customers to ship deeply integrated AI agents—owning everything from agent design and evaluation to the backend services, data systems, and cloud infrastructure that make them production‐ready. You'll partner closely with our Forward Deployed … volume for senior engineering roles. Hands‐on fluency with the full AI stack. Deep familiarity with LLMs and agent systems, evaluation frameworks, backend and API design (Python or TypeScript), data systems (PostgreSQL, DynamoDB, MongoDB, or similar), and cloud infrastructure (AWS, Azure, or GCP) including Kubernetes, Docker ...

Back End Development Lead

Hiring Organisation
Oyster Consultants
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£70,000 - £80,000 per annum
evolve our stack and make constant improvements. Required Skills/Experience Strong C# development experience Experience with both .NET Core and .NET Web API Experience of building Microservices in .Net Core Experience using Message Based Architectures Experience using both SQL & NoSQL technologies Experience of API design Cloud ...

Software Engineer

Hiring Organisation
Corpay
Location
Central London, London, United Kingdom
Employment Type
Permanent, Work From Home
division. This position falls under our Cross Border line of business and is located in London. In this role, you will contribute to the design and development of our eMoney and FX payment systems. You will report directly to the Engineering Manager and collaborate closely with Product, Design … will set you up for success by providing: Assigned workspace or home office setup Company-issued equipment Role Responsibilities Provide significant contribution to the design, development, and maintenance of secure and scalable payment systems. Collaborate with engineering managers, designers, and product teams to gather and analyse requirements, implement technical ...

Technical Architect - Pre-sales

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
client data will be sourced, validated, and integrated into Mondra, leveraging where possible our existing Import and Export APIs and identifying where custom API development may be required for fulfil Mondra’s data requirements. You will also contribute to the client contracting process, ensuring technical commitments are clearly defined … including mapping data sources, transformation logic, and validation processes. Identify the client’s BI requirements, and define data export strategies (preferably via existing Mondra API). Identify the authentication/authorisation capabilities of the client, and promote the integration with Mondra’s Identity Provider via Single Sign On. Leverage ...

Full Stack Engineer

Hiring Organisation
Total Recruitment Group
Location
West London, London, United Kingdom
Employment Type
Permanent
Salary
£85,000
role, with strong backend expertise in Typescript and Node and front capability in React Proficiency in SQL, Redux, cloud services (AWS or GCP), RESTful API design and GraphQL Strong analytical skills with the ability to design, optimise, and troubleshoot complex UIs Excellent communication and leadership skills; ability ...

Senior Full Stack Engineer (GCP, Python, JavaScript) Remote

Hiring Organisation
Exalto Consulting
Location
London, United Kingdom
Employment Type
Contract
Contract Rate
£400 - £410/day
assisted development workflows. ● Agile Experience: Proven track record working within Agile teams and participating in iterative delivery. ● Core Engineering: Proficiency in Git, REST API design, and modern CI/CD practices This is a great opportunity to work for an exciting organisation and to start ASAP. The role ...

Staff Software Engineer

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
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) If you are looking for a new challenge, then ...

Senior Python Engineer: AI Agents & Forecasting

Hiring Organisation
Jobleads-UK
Location
Greater London, England, United Kingdom
LangChain or LangGraph (agent memory, tool calling, state management) Dagster in production (assets, sensors, partitions) or equivalent pipeline orchestration Strong backend fundamentals including API design, async programming, and database modelling You've built systems that had to work reliably at scale, not just pass a demo Experience 5+ ...

Lead Software Engineer

Hiring Organisation
MARSH CORPORATE SERVICES LIMITED
Location
City of London, London, United Kingdom
Employment Type
Permanent, Work From Home
products (e.g., Concierge an agentic AI workflow tool, Prism a Mercer knowledge fabric for scheme data, and similar initiatives), from problem framing and design through build, release, and support. Translate risk advisory/consulting needs into clear technical requirements, user stories, and solution designs; partner with stakeholders through … Proven experience as a Tech Lead/Lead Engineer delivering production software, including hands-on coding and code review ownership. Strong backend engineering skills (API design, data modelling, performance) and experience building secure, role-based applications. Experience working directly with business stakeholders in a financial firm, with ...

Senior Developer

Hiring Organisation
Addition
Location
London, South East, England, United Kingdom
Employment Type
Full-Time
Salary
£70,000 - £90,000 per annum
improving APIs that support critical platform functionality Investigating production issues and tracing problems across distributed systems Working with product and engineering teams to design scalable solutions Improving reliability, observability and performance across existing services Reviewing code, sharing knowledge and helping raise engineering standards across the team Tackling real-world … APIs used by customers or internal teams Other Skills Needed: Solid backend engineering experience in C#, Java, or Go, with a strong grasp of API design and architecture. Hands-on experience managing and debugging production systems across cloud and self-managed infrastructure. Proven ability to navigate complex third ...

Ruby Developer

Hiring Organisation
Proactive Appointments
Location
London, United Kingdom
Employment Type
Permanent
Salary
GBP 70,000 - 80,000 Annual
develop new features, enhance existing systems, and ensure our platform remains stable and efficient. Your deep understanding of Rails architecture, PostgreSQL optimisation, and API design will be essential as you contribute to ongoing development projects. If you enjoy collaborating in Agile/Scrum environments, value clean code ...

Ruby on Rails Backend Engineer

Hiring Organisation
Rise Technical Recruitment
Location
Fulham, London, United Kingdom
Employment Type
Permanent
Salary
£60000 - £80000/annum Private Healthcare + Holiday + Pensi
evolution of core Ruby on Rails operational platforms. Optimise PostgreSQL performance and Sidekiq background job efficiency. Manage secure third-party integrations and RESTful API design. Partner with Platform teams on AWS and CI/CD reliability. The Person: Deep experience with Ruby on Rails and OOP. Expert in PostgreSQL ...

Principal Data Architect

Hiring Organisation
Experis
Location
City of London, London, United Kingdom
Employment Type
Contract
Contract Rate
£700 - £800 per day
Data platforms - Fabric, Snowflake, CosmoDB, DataBricks, MongoDB, RDBMS Data replication/CDC - Qlik Replicate, Oracle Golden Gate Data modeling - ERStudio Message-oriented data movement API design and access Data Analytics and AL/ML - AzureML Data virtualization Streaming data Data integration and ETL/ELT Tools - Matillion, Alteryx … NoSQL data stores, methods, and approaches (star and snowflake, dimensional modelling and third normal form) Experience with data security and data access controls and design Deep understanding of SoX, GDPR and Regulatory/CNI control environments In-depth experience in providing resolution to an extensive range of complicated data ...

Senior Software Engineer

Hiring Organisation
Platform Recruitment Limited
Location
City of London, London, United Kingdom
Employment Type
Permanent
heavily backend-biased position but given the size of the team you will be working across the stack when needed Build scalable, performant systems Design and deliver end-to-end features with direct impact on customer value Work with product and ML teams to help translate abstract and complex … software function About you: Strong ability across scalable and performant systems You have a product mindset Statically typed language expertise Experience with API design Low ego and love of engineering Full details are available. Please don't hesitate to get in touch for more information. ...

Software Engineer

Hiring Organisation
Platform Recruitment
Location
City of London, Greater London, United Kingdom
Employment Type
Permanent
Salary
£90000 - £160000/annum
heavily backend-biased position but given the size of the team you will be working across the stack when needed Build scalable, performant systems Design and deliver end-to-end features with direct impact on customer value Work with product and ML teams to help translate abstract and complex … software function About you: Strong ability across scalable and performant systems You have a product mindset Statically typed language expertise Experience with API design Low ego and love of engineering Full details are available. Please don't hesitate to reach out for more information. ...

Senior Software Engineer II (Java/ Spring)

Hiring Organisation
Elsevier
Location
Greater London, United Kingdom
Employment Type
Full Time
Salary
100400 to 167300 EUR Annually
Senior Software Engineer II , you will work with a passionate team that delivers scalable, reliable, and innovative solutions that accelerate scientific discovery. Key responsibilities: Design and implement graph-based search services. Develop applications using Java , Spring Boot, Spring, GraphQL , and GraphQL Federation . Integrate with databases, web services … Proven track record building scalable backend systems and APIs. Strong expertise in Java and the Spring Boot ecosystem . Hands-on experience with GraphQL API and REST API design. Solid background in cloud-native architectures with AWS and Kubernetes (EKS) . An advocate of best practices for rapid ...

IT Solutions Architect (Integration / Azure)

Hiring Organisation
DGH Recruitment
Location
City of London, London, United Kingdom
Employment Type
Permanent, Work From Home
that supports business critical functions across the business. My client have migrated significant services to the cloud and now requires a lead architect to design and build the next generation of solutions including core finance and HR technology landscape, automating data flows, integrating systems, supporting in the delivery … real-time reporting and analysis, whilst driving a more mature awareness to data architecture and governance across the business. Responsibilities: - Lead the design and delivery of integrations across technology platforms and solutions. - Produce architectural documentation (HLDs, LLDs, diagrams, support guides). - Ownership of integration and application architecture in alignment ...