Citi★3.9 (21k)· London

You will work with TypeScript, React, HTML5, CSS, JavaScript (ES6+), Chromium/Electron/OpenFin, FDC3, REST/WebSocket APIs, Kafka/Solace/Tibco, and CI/CD with Jenkins. The team delivers pricing solutions and trading GUIs for Citi’s Foreign Exchange business. You will provide technical leadership, mentor junior engineers, and drive AI integration.

Lead a disputes team at Checkout.com, working with a .NET/C# back end, React/TypeScript front end, and Python for machine learning, alongside REST APIs, event-driven microservices, and SQL. The team builds tools and models to help merchants manage and win chargeback disputes at scale. You will oversee engineers across disciplines and seniority levels, driving predictable delivery and operational efficiency.

Work with Azure (API Management, Logic Apps, Service Bus, Functions, Data Factory, Synapse), .NET/C#, PowerShell, SQL/NoSQL, and AI tools like GitHub Copilot. You will design and develop secure data integrations across the Azure middleware estate for the All England Lawn Tennis Club, which stages The Wimbledon Championships.

Develop backend services using Node.js, Python, Java, C#, PHP, and Ruby on Rails, with databases including MySQL,

Senior Developer role working with C#, .NET 4 & 6, SQL Server, Azure cloud services, SignalR, RabbitMQ, Kafka, Azure Service Bus, and CI/CD via Azure DevOps in an Agile environment. The team delivers a complex SaaS product for a regulated financial marketplace, requiring experience in financial or trading software.

Lead Python Developer role using Core Python, Flask, VueJS, JavaScript, CSS, HTML, SQL, AWS, Terraform, Docker, and serverless components, with CI/CD and Agile practices. The developer builds, enhances, and supports production applications within UK public sector programmes, collaborating with delivery, product, and data teams.

BNY★3.5 (5.5k)· London

You'll use Java 17/21 with Spring, Maven, Groovy, JavaScript/TypeScript (Angular), Docker, GitLab CI/CD, IntelliJ, Windsurf, Splunk, and AppDynamics to build secure backend services, batches, and APIs for a global financial services company.

Checkout.com★3.8 (15)· London

Senior Engineering Manager leading the Disputes team, which builds tools, services, and machine learning models to help merchants manage and win chargeback disputes at scale. The team owns a full stack centered on .NET / C#, React and TypeScript front ends, Python-based ML, and event-driven microservice architectures.

Work with Java, Python, JavaScript/TypeScript, Go, cloud platforms (AWS, Azure, GCP), CI/CD pipelines, and version control. Guiding the technical direction of BabuSpace’s premium short-term rental marketplace platform for African cities, designing backend architectures, and mentoring engineers.

Principal C#/.NET engineer leading solution design and hands-on development using C#, .NET Core, MongoDB, SQL Server, Kafka/ActiveMQ, and OpenShift/Kubernetes. Mentors developers and directs engineering, applying SOLID, microservices, and contract-first API design within a regulated financial services environment.

You will work with Python, JavaScript, SQL, Kafka, AWS/Azure, PostgreSQL, SQL Server, ClickHouse, and MongoDB. The team designs and delivers real-time, high-performance trading systems for Energy & Commodities, integrating market data, risk, and front-to-back office workflows.

Java 11+, Spring Boot, microservices, event-driven architecture, Terraform, and cloud platforms (Azure, AWS, or GCP). The team builds post-trade technology solutions including business-critical applications, APIs, client reporting platforms, and web portals for capital markets. You will mentor developers and contribute to architectural decisions.

Java and Spring Boot, React, AWS, and CI/CD pipelines are the primary technologies. You will build microservices-based customer-facing applications for a leading retail bank’s cloud-native digital banking platform. No team size is stated.

Design, build and deploy production Generative AI applications, LLM-powered solutions and agentic frameworks using Python, LangChain, LangGraph, and OpenShift. You will automate enterprise workflows with intelligent agents, working with PostgreSQL and pgvector as part of Citi’s COO-Technology team building scalable AI for global operations. This is an Individual Contributor Staff Engineer role.

You will work with Unix/Linux, JavaScript, a ticketing system, and networking infrastructure tools. As a Support Engineer on the Global Support Engineering team, you will resolve technical issues with ExtraHop's network detection and response (NDR) product and assist customers with hardware, firmware, and third-party integrations.

NatWest Group★3.7 (1.2k)· London

You'll work with Mainframe hardware (DASD, SAN/FICON, IBM z), automation scripting (Python/Shell), infrastructure as code, GDPS, and CI/CD pipelines. As part of NatWest Digital X, you'll engineer hardware solutions for the Mainframe environment, applying automation to improve products. This technical lead role guides a team but no team size is specified.

The role involves troubleshooting network infrastructure, hardware, firmware, and third-party integrations using a ticketing system and video/phone channels. Preferred technologies include Unix/Linux

Design, configure and manage Mainframe Hardware solutions including DASD, SAN/FICON connectivity, and network infrastructure, using automation scripting (Python or Shell). You will engineer infrastructure-as-code for the Mainframe environment at NatWest Digital X, supporting hardware migrations between IBM z Mainframes and GDPS architectures. This is a technical lead role.

C# .NET, Azure, SQL Server, Kafka, IBM MQ, FIX Protocol, event-driven and microservices architectures. You will define the architecture for enterprise trading platforms, modernising front, middle and back-office systems within a global financial services organisation.

Palantir★3.9 (37)· London

You’ll work with Java, C++, Python, TypeScript, JavaScript, Kubernetes, Cassandra, Chromium, and open-source tools. As a new-grad infrastructure engineer, you’ll contribute to the shared infrastructure behind Palantir Foundry, Gotham, and Apollo—platforms deployed at key public- and private-sector institutions—as well as to Rubix and Mission Manager for sensitive environments. Teams are small, focused on backend, developer, frontend, or storage infrastructure, or on production infrastructure including a Kubernetes-based PaaS, Apollo, and Signals.

Palantir★3.9 (37)· London

Interns contribute to shared infrastructure powering Palantir Foundry, Gotham, and Apollo, plus internal tools like Rubix and Mission Manager. Work spans backend, developer, frontend, or storage infrastructure using Java, C++, Python, TypeScript, or JavaScript, alongside Kubernetes, observability tools, and production PaaS.

Design, build, and deploy LLM/RAG pipelines, agentic workflows, and backend APIs in Python on Azure. You will drive production-grade AI for lending, deposits, risk, and customer experience at Shawbrook Bank. Mentor other engineers in the AI Engineering squad.

Microsoft★4.2 (9k)· London

This role involves coding in C, C++, C#, Java, JavaScript, or Python, applying AI, LLM tooling, and CI/CD practices. Engineers join a cross-functional team of software engineers, data scientists, and designers to build production-ready, AI-powered solutions for strategic customers, owning end-to-end system design for cloud and AI workloads.

Nuffield Health★3.2 (939)· London

You will work with Java 21, Spring Boot, Maven, RabbitMQ, Apache Camel, Git, GitHub Actions, Docker, Azure DevOps, Terraform, Ansible, and SQL databases. The Integration Squad designs, develops, and supports microservices and APIs for Nuffield Health's digital healthcare platforms, enabling secure connectivity across internal and third-party systems.

MAREX★3.2 (6)· London

You will work with C# .NET, JavaScript, TypeScript, React, Node.js, GraphQL, Docker, NoSQL/RDMS databases, and AWS cloud services (ECS/EKS, Lambda, S3, RDS, API Gateway). The team builds and maintains applications to strengthen the company’s market-making capabilities and improve operational efficiency across multiple asset classes and geographies.