You will build a fully bespoke blockchain from scratch using Rust, C++, CUDA, Python, Shell for the protocol layer; Solidity, Foundry, Hardhat for smart contracts; and TypeScript with React, Next.js, Node.js for frontends. This greenfield project powers Arena Entertainment’s digital entertainment platforms, spanning gaming, DeFi and Web3.

Zaizi★4.0 (5)· London

Building mission-critical web apps, APIs, and microservices (TypeScript, React, Node.js, Python) plus native Android/Kotlin tactical systems with AIDL IPC and CoT routers for MoD programmes. Working on edge platforms (TAK) with CI/CD (Docker, GitLab CI) and NCSC Secure by Design standards. Mentoring mid-level engineers.

Google★4.3 (6.2k)· London

You will work with C++, Java, Kotlin, TypeScript, front-end frameworks, API development, machine learning, agentic coding, and GCP. This role is in Google Labs Science, which partners with DeepMind to transform GenAI research (e.g., Co-Scientist, AlphaEvolve) into products that accelerate scientific discovery.

Build Python (FastAPI/Flask) features for the NHS Digital Onboarding Service (DOS) within a serverless architecture, paired with a NextJS/React client frontend. The service is part of the NHS API Platform.

Senior UI Software Engineer role at Citi building trading GUIs for the Foreign Exchange business, covering full development lifecycle with technical leadership. You will use TypeScript, React, JavaScript, HTML5/CSS, FDC3, REST/WebSocket APIs, Kafka/Solace/Tibco, and CI/CD tools like Jenkins, with desktop container experience in Chromium/Electron/OpenFin.

Work with Kotlin, SQL/noSQL, TensorFlow Lite, Coroutines, Flow, and REST/gRPC to build a production Android app for an AI-powered proactive smart assistant that handles multi-step workflows and real-world task completion.

Build and maintain iOS applications using Swift and SwiftUI, integrating AI features backend APIs and on-device inference with TensorFlow Lite. The team is building an AI-native proactive smart assistant that handles long-running workflows, multi-step reasoning, and real-world task completion for everyday users.

You will work daily with TypeScript, React, and Python across the full DeepEditor stack. The product is an AI-powered performance editing tool for Hollywood studios. As the technical anchor, you will mentor a growing team of fifteen engineers.

You will work with Python, AWS, and Kubernetes supporting the Forward Deployed Engineering team at a pre-seed voice AI startup building infrastructure for emerging markets, processing thousands of daily calls with proprietary speech models.

Build AI-enabled products using Python, TypeScript, Java or Go at a YC-backed AI start-up. Work directly alongside founders to ship customer-facing solutions and shape both product and engineering culture from day one.

You will work with Python, Node.js, PyTorch, OpenAI/Anthropic/open-source LLMs, SQL & NoSQL, Kubernetes, and Docker. You own the inference and orchestration layer for a proactive smart assistant that handles multi-step reasoning, tool calls, and long-running workflows, turning model capabilities into stable, production-grade APIs.

Build and ship AI features using Python, PyTorch/JAX, LLMs (OpenAI-style APIs, LLaMA, Qwen), vLLM, and vector DBs. You'll work on a proactive smart assistant that handles long-running workflows, persistent context, multi-step reasoning, and external tool interaction for everyday users.

Junior Frontend Engineer role at Fortex, within Valton Sport Agency, working with HTML, CSS, JavaScript, and modern frameworks like React or Next.js. The team of designers, engineers, and strategists builds digital products, interfaces, and brand identities for clients. The role includes mentorship from senior engineers and work on real client projects.

VueJS 3, JavaScript (ES6), HTML5, CSS3 (SASS), RESTful APIs, GIT, Azure DevOps (CI/CD), Jest, Cypress/Playwright. Build and maintain modern web applications, developing reusable UI components and ensuring responsive, accessible, performant frontends.

Tecknuovo★0.0· London

You'll work with React, TypeScript, Node.js and/or Python, AWS or Azure, infrastructure-as-code, containerised workloads, CI/CD pipelines, and relational and NoSQL databases. You'll deliver end-to-end features across frontend, backend, and cloud for cloud-native digital services in government and enterprise environments, working in a high-performing Agile delivery team.

Python (FastAPI), TypeScript (Express), AWS (serverless), Terraform, Docker, PostgreSQL, DynamoDB, GitHub Actions, and React. The team builds the Orchestra control plane for data and AI, used by enterprises like Experian and Octopus Energy.

Full Stack Developer role using C#, .NET, JavaScript, and Umbraco for an established luxury travel company. The work involves a major transformation programme building web-based tools to automate operational tasks, improve pricing accuracy and management information, plus website enhancements.

Build pipelines and models using Python, TypeScript, and Next.js to transform unstructured data into structured, queryable formats for an AI platform supporting private-equity reasoning. You will join a six-person founding technical team focused on NLP, information extraction, and representation learning.

You will work with React, modern JavaScript/TypeScript, and APIs. As part of a fintech engineering team, you'll build data-intensive platforms that support business-critical workflows, taking ownership of features from design to deployment.

Python backend primarily, with frontend work across the stack. Builds features end-to-end for a B2B SaaS company creating AI and automation products for people-intensive industries.

You’ll work with Python, Docker, CI/CD, AWS or Azure, SQL, Linux, Bash, Git/GitHub, and optionally Streamlit, Rust/C/C++ or React. You’ll join the Internal Tools team at an AI scale‑up building the systems that deploy, operate and scale its flagship AI product for data‑centre energy efficiency.

This Senior Full Stack Developer role involves Python, TypeScript, React, SQL, PostgreSQL, Large Language Models (LLMs), prompt engineering, and AI coding tools. You will own and develop the company’s flagship AI platform, building data pipelines and full-stack features that solve strategic challenges for clients. You will work within a small engineering team.

Appvia★0.0· London

You’ll work with Java, Spring Boot, TypeScript, MongoDB, Docker, Kubernetes, Maven, and GitLab. You’ll join a client-facing software engineering practice delivering a modernisation and AI-enabled transformation programme as a greenfield build within a brownfield ecosystem.

You will build and maintain data-focused, high-performance front-end products using JavaScript/TypeScript, with server-side languages (C#, Java, NodeJS, SQL) and frameworks like React/Redux as nice-to-haves. The Trade Desk is a global digital advertising platform, and you'll own full-lifecycle development of features for user-facing interfaces. With 7+ years of experience, you'll work on an agile, distributed team spanning multiple time zones and continents.

You'll work with React (Vite), Tailwind, Node.js, Express, tRPC, PostgreSQL, and Elasticsearch, building scalable APIs and front-end features. The company is a high-growth B2B SaaS firm creating an advanced property data platform for UK property professionals, integrating thousands of data sources. This hands-on leadership role also involves mentoring engineers and shaping architecture.