Citi★3.9 (21k)· London

You will work with Java, Spring, Web3J/Web3JS, Solidity, Docker, and Hardhat/Foundry to build Citi’s Integrated Digital Assets Platform (CIDAP), integrating blockchain networks and digital asset infrastructure.

Citi★3.9 (21k)· London

Work with Solidity, Web3J/Web3JS/Ethers.js/Viem, Java/Spring, Node.js, and blockchains such as Ethereum, Hyperledger Besu, Canton, and Solana, using Hardhat/Foundry/Truffle for testing. Contribute to Citi's Integrated Digital Assets Platform (CIDAP) building Web3 components for tokenization, smart contracts, and on-chain settlement.

Zoopla★3.9 (18)· London

A 12-month maternity cover role on a dual-stack C#, .NET, and TypeScript backend with React microfrontends, using AWS managed services (ECS/Fargate, Lambda, SQS, DynamoDB, DocumentDB) and Terraform/SST. You'll build B2B SaaS software for estate agents and home builders at Alto Software Group. Take end-to-end ownership of features from design to production, working with the product team and AI coding agents.

You'll work primarily with TypeScript, Node.js, and PostgreSQL on GCP, designing and building scalable backend systems. The team develops and maintains a robust investment platform that powers features like mutual funds, bonds, and family investment tools.

DeepL★3.8 (4)· London

Work with Kubernetes, Terraform, ArgoCD, Go or Python, and AWS across hybrid on-prem and cloud infrastructure. The Hybrid Platform Engineering track builds and operates the compute layer—Kubernetes control plane, networking, storage, and core services—powering DeepL's language AI products and research. The role involves deepening the hybrid model and unifying workloads across on-prem and AWS.

Lead DevOps Engineer: work with AWS, Azure, GCP, Terraform, Linux/Unix, Python/Go/PowerShell/Nodejs/C#, and CI/CD tools (Octopus/TeamCity/Jenkins/Azure DevOps). Role is at a tech consultancy building and running cloud infrastructure, automating deployments with IaC, and managing a team of engineers.

Work with Kotlin, Java, Spring Boot, microservices, REST APIs, Node.js, TypeScript, Express.js, Nunjucks, AWS/Azure/GCP, Docker, Kubernetes, Terraform, and CI/CD tools. You'll build secure, scalable digital services on large-scale transformation programmes for the Public Sector and Healthcare within Agile, multidisciplinary teams. Mentoring other engineers is expected.

Full Stack Developer role at a specialist investment business. You'll use TypeScript, JavaScript, Python, React, Next.js, Node.js, RESTful APIs, relational/NoSQL databases, Azure, Git, and CI/CD to build and evolve the technology platform with the existing team and senior stakeholders.

You'll work across the full stack—backend distributed systems, cloud with IaC, and data pipelines including vector stores—using tools like Claude Code and AI agents for code review, refactoring, and parallel work. This Principal Engineer role on a large iGaming engagement oversees sportsbook, casino, and gaming platforms for a major client, managing a group of engineers and Tech Leads as the named delivery owner. The team includes engineers and Tech Leads that you directly line manage.

Koinly★3.0 (1)· London

Work with React 19, TypeScript, TanStack (Router, Query, Table), Radix UI, Mantine, Tailwind CSS v4, Vite, Vitest, Storybook, Highcharts, Sentry, Bun, and RabbitMQ on a data platform that reconciles crypto transactions and tax obligations for Koinly’s web application, with a React Native mobile app joining scope later.

Koinly★3.0 (1)· London

You will work with TypeScript on Bun, RabbitMQ, Redis, PostgreSQL, Vitest, Sentry, and Rust. The team owns the distributed data-processing backend that ingests, normalizes, and reconciles on-chain and exchange data for Koinly’s crypto tax calculation product.

You'll work with frontend (TypeScript, React, Angular, Vue, Next.js, Tailwind), backend (Python, Node.js, Java/Spring, C#/.NET), databases (SQL, NoSQL, vector databases), LLM frameworks, and cloud platforms (Azure, AWS, GCP) including Docker and CI/CD. QuantumBlack, an AI division of McKinsey, builds industry-shaping products and tools across diverse industries by pairing software engineers, AI engineers, and data scientists with client leadership. As a Senior Software Engineer, you'll lead architecture design, mentor teams in engineering excellence and Agile practices, and drive technology decisions on scalable solutions.

You'll work with TypeScript, Node.js, AWS serverless technologies (Lambda, SQS, EventBridge, API Gateway), MongoDB, Terraform, and GitHub Actions. Seccl is an embedded investment platform helping people invest better, owned by Octopus. You'll design and operate services within cross-functional squads, mentor engineers, and support regulated investment operations in a build-and-run model.

You’ll work across full-stack engineering with AI tooling (Claude Code, agents, evals), cloud/IaC, distributed systems, APIs, data pipelines and vector stores on iGaming platforms (sportsbook, casino, gaming) for a major client. You’ll oversee a group of engineers and Tech Leads, line-managing leads and owning delivery.

Senior WordPress Developer role: build bespoke WordPress sites and apps using PHP, MySQL, ACF, WooCommerce, Gutenberg, JavaScript (ES6+), SASS/SCSS, Git, Composer, npm, Vite, CI/CD. You’ll also drive AI-assisted development (RAG, MCP, Copilot) and mentor junior developers.

You will join a squad building commercial offerings on the open-source Backstage framework, designing backend systems, APIs, and developer portals. You will work primarily with TypeScript, Node.js, and React, and build CI/CD pipelines and infrastructure.

This role involves working with React/Next.js, Node.js, TypeScript, and AWS for cloud-native development, plus REST APIs, microservices, CI/CD, and automated testing in Agile teams. No specific product or project is described, and the company’s own business is not detailed.

Build and maintain the company’s platforms using JavaScript, Node.js, Next.js, Express.js, React/React Native, .Net 4.8/9/10, C#, HTML/CSS, and API Restful Services. You will develop both web and mobile applications, collaborating with the team while working independently.

DeepL★3.8 (4)· London

Work with React, TypeScript, Node.js, WebRTC, WebSockets, and streaming architectures. You will join DeepL Voice, building real-time interpretation features for fluid conversations and audio streams. This is a 0-to-1 engineering environment in a cross-functional squad.

Principal engineers work with Claude Code, AI agents, full-stack backend (distributed systems, APIs, data modelling), cloud (IaC) and data pipelines (vector stores, embeddings). They oversee a group of engineers and Tech Leads on a major iGaming engagement building sportsbook, casino and gaming platforms, owning delivery and steering the teams.

Checkout.com★3.8 (15)· London

You'll work with REST/JSON APIs, Postman, JavaScript, React, Angular, Java, .NET, Python, Node, and payment technologies like 3DS, tokenisation, and Apple/Google Pay. As a Sales Engineer, you'll support clients integrating Checkout.com's online payments platform, which powers transactions for companies like eBay, Uber, and Spotify.

Linux Recruit★3.0 (1)· London

Work with PyTorch, distributed training libraries, Slurm, Kubernetes, and AWS multi-node GPU clusters to architect and optimize large-scale model training pipelines. You will join a stealth AI startup at the intersection of robotics and embodied AI, building the infrastructure that powers next-generation AI breakthroughs.

MAREX★3.2 (6)· London

Design and implement resilient data ingestion, orchestration, and provisioning using APIs, event streaming, CI/CD, and infrastructure-as-code for Marex's enterprise data products. This role supports the firm's global financial services platform by delivering trusted, reusable data assets and integration capabilities for operational, regulatory, and analytical use cases.

Echobox★4.0 (1)· London

You will work with Python, Java, or Node.js, back-end frameworks, SQL/NoSQL databases, RESTful APIs, microservices, Git, and AWS/GCP/Azure. You will build and maintain back-end services and systems supporting AI-powered products that help online publishers.

Echobox★4.0 (1)· London

You will work with Python, Java, or Node.js, SQL and NoSQL databases, RESTful APIs, microservices, Git, and cloud platforms (AWS, GCP, Azure) to build and maintain back-end services. The company develops AI that helps online publishers like The Times and Le Monde overcome daily challenges, and you will collaborate with data scientists and product teams to support these AI-powered products.