Lead engineers use Java, C#/.NET, Python, TypeScript, JavaScript, React, Go, Ruby, Scala, R, and SQL; Git, MacOS/Linux, and CI/CD; and AI-assistive tools. They lead multi-client software consultancy engagements, building and delivering production agentic systems and ML-powered features. The team is typically one to two clients per year.

This role develops generative AI applications using Java, Python, React or Angular, LangChain, LlamaIndex, Hugging Face, Docker, Kubernetes, and AWS, with tools like GitHub Copilot. You will build scalable, AI-powered solutions for Citi’s global finance operations.

You will lead mobile development for the BUSY App across iOS, Android, macOS, watchOS, and Wear OS, using Swift, Kotlin, and Apple/Android ecosystems, with BLE and hardware communication as nice-to-haves. Your team builds the BUSY ecosystem—a cross-platform productivity app paired with the BUSY Bar smart multi-tool—at Flipper Devices, creator of Flipper Zero.

8th Light★0.0· London

You will use Java, C#/.NET, Python, TypeScript, JavaScript, React, Go, Ruby, Scala, SQL, Git, CI/CD, and AI-assistive tools. As a lead technologist at a technology consultancy, you will lead client engagements building agentic products, platforms, and full ML lifecycle systems. You will mentor colleagues and lead architecture discussions on complex projects.

Atlas Technica★4.4 (10)· London

Work with Microsoft Azure, Microsoft 365/Office 365, Active Directory, PowerShell, SQL, ConnectWise Manage/ScreenConnect/CPQ/BrightGauge, NinjaOne, Addigy, REST APIs, Microsoft GDAP, and Lighthouse. Design, implement, and support scalable multitenant IT solutions for hedge funds and investment firms. Provide second-line support and automation.

You will work with AWS, IAM, JumpCloud/Okta, Google Workspace, M365, MDM, scripting (Python, PowerShell, Bash, Google Apps Script), and networking. The role supports a purpose-led UK organisation’s technology team, managing identity, SaaS, endpoints, security tooling, and cloud infrastructure to keep systems secure, scalable, and reliable.

You'll work with SASE/ZTNA, Apple (iOS/macOS via Jamf), Jamf Pro, Apple Business Manager, Android Enterprise, scripting (bash/zsh/Python), APIs, and AI/LLM tools. As part of the End User Experience Engineering team at a global investment firm, you'll engineer and operate endpoint platforms including remote access, Apple/mobility, and general end-user platforms.

Copper★0.0· London

You will work with Microsoft Entra ID, AWS IAM Identity Centre, Wiz, Microsoft Defender, ArmorCode, PowerShell, Python, Bash, Terraform, and Microsoft Sentinel. Copper builds institutional digital asset infrastructure focused on custody (using MPC technology), collateral management, and prime services, including the ClearLoop platform.

Atlas Technica★4.4 (10)· London

Works with Microsoft Azure, Microsoft 365, Active Directory, PowerShell, SQL, ConnectWise Suite, NinjaOne, Audigy, and REST APIs. Serves as a subject matter expert designing, implementing, and supporting multitenant IT solutions for internal teams and external clients (hedge funds and investment firms), identifying automation opportunities and providing second-line support.

NatWest Group★3.7 (1.2k)· London

You'll work with scripting and orchestration, Atlassian products (Jira, Confluence, Jira Service Management), Workato, Jamf Pro, MacOS, Google Workspace, Slack, GitHub, and IAM/SSO tools. As part of the Colleague Technology Services team, you'll automate and manage NatWest Boxed's internal technology environment and productivity solutions. This is a technical lead role.

You'll use scripting and orchestration tools, Atlassian products (Jira, Confluence, Jira Service Management), Workato, Jamf Pro, MacOS, Google Workspace, Slack, GitHub, and identity/access management tools. As part of the Colleague Technology Services team at NatWest Boxed, you'll manage and automate internal technology applications and operational processes to improve efficiency.

Citi★3.9 (21k)· London

Build and scale AI-powered financial systems using Java, Spring, React/Angular, Python, FastAPI, Docker, and GitHub Copilot within Citi’s global tech environment. You will design generative AI agents, LLM workflows, and RAG pipelines while working on enterprise microservices, mobile, or front-end development. This role is for an individual contributor on an agile team.

You will design, train, and deploy deep learning models (PyTorch/TensorFlow) alongside classical computer vision pipelines (OpenCV, geometric vision) into Python-based Docker microservices and ONNX Runtime C++ desktop applications. You will work on Catapult's centralized Data Science team to build production-ready algorithmic features for sports-performance analytics used by elite professional teams.

Senior Security Engineer will work with Microsoft Entra ID, AWS IAM Identity Centre, Wiz, Microsoft Defender, ArmorCode, Terraform, PowerShell, Python, Bash, APIs, and Microsoft Sentinel. The role designs, implements, and maintains security controls for Copper’s institutional digital asset custody, collateral management, and prime services infrastructure, focusing on cloud, endpoint, identity, and network security.

Senior Cyber Security Analyst using EDR, SIEM, cloud-native (AWS, Azure, GCP), and Microsoft 365 tools. You will investigate and respond to cyber threats within Sky’s Cyber Defence Department, acting as escalation for L2 analysts and collaborating with threat hunting and engineering teams.

AJ Bell★3.7 (37)· London

You will work with the Microsoft security stack, firewalls, cloud security solutions, email/web gateways, Privileged Account Management, Identity Governance and Administration, SIEM, endpoint protection, and scripting for automation across Windows, MacOS, Linux, and mobile platforms. As principal technical lead you oversee day-to-day security engineering execution, ensuring project engagements align with security strategy at AJ Bell, a UK investment platform.

Design, develop and maintain software solutions using C#, Java, Python, or JavaScript/TypeScript for APIs, relational databases (SQL), and Git. The role builds internal applications, integrations, and automation to support a creative production agency’s operations and workflows. Works under the COO.

Catapult Sports★3.8 (4)· London

Work with Python, C++, PyTorch/TensorFlow, OpenCV, Docker, AWS, ONNX Runtime, and TensorRT to develop computer vision algorithms for sports performance analytics. As part of Catapult’s Data Science team, you’ll build end-to-end pipelines from video ingestion to production inference, delivering insights for professional teams.

Hands-on MDM at scale (1,000+ devices) using Addigy, Jamf, Intune; EDR/XDR (CrowdStrike, SentinelOne, Microsoft Defender); ZTNA; DLP; work app isolation platforms; Google Gemini, Claude. As the London office’s walk-up IT support, you also globally own the endpoint security stack—MDM, Zero Trust, DLP, and hardening across MacOS, Windows, iOS, Android. 8x8 provides AI-native customer-experience and communications technology.

WTW★3.6 (1.7k)· London

Works with Microsoft Defender XDR (Endpoint, Identity, Office 365, Cloud Apps), Microsoft Sentinel, Security Copilot, Purview DLP, Insider Risk Management, and deception platforms like Thinkst Canary. Leads the enterprise cyber deception and unified detection/response programme within WTW’s Global ICSD function. Also leads and grows a team of Defender XDR and Deception Engineers.

Apple★4.1 (14k)· London

You will design and ship Swift frameworks and XPC services that form the on-device client side of Apple's privacy-preserving cloud inference platform, using Protocol Buffers, async/await, GCD, and Instruments for profiling. Your code handles every Apple Intelligence and Foundation Models request before it leaves iPhone, iPad, Mac, or Vision Pro.

Proton★5.0 (1)· London

Join Proton's Inbox Desktop team to rebuild the Proton Mail Desktop App, Mail Bridge and Export tool using a cross-platform Rust stack. You'll work with Golang, C++, Qt, JS, TypeScript, React, Electron and standard dev tools (Git, GitLab CI, Jira). You’ll take technical ownership of the Windows and Linux desktop clients within a cross-functional team of about 60 engineers.

Proton★5.0 (1)· London

Engineering Directors at Proton set technical direction and work with PHP (Symfony), Rust, Python, Swift, Kotlin, Jetpack, Typescript, React, C#, SQL, Redis, MySQL, and Ceph across mobile, desktop, web, and backend platforms. They lead engineering for one of Proton’s existing or upcoming products—such as Proton Mail, VPN, Calendar, Drive, or Pass—which provide private, secure, open-source tools to over 100 million users. The role involves managing a team of managers and driving DevSecOps practices.

Funding Circle★3.5 (53)· London

You will work with React Native, React.js, TypeScript, Firebase, Gradle, XCode, REST APIs, and CI/CD for app releases on iOS and Android. The role involves building and scaling a mobile app for Funding Circle’s fintech platform that uses data to provide fast funding to small businesses.

You'll build transcription features end-to-end for Granola's desktop app using TypeScript, Node.js, React, and Electron, working with audio capture APIs, speech-to-text models, and native OS code (CoreAudio, WASAPI). The founding team is creating the best desktop transcription application, handling everything from audio capture and echo cancellation to diarization and UI/UX across macOS and Windows.