Build REST and GraphQL APIs and MCP servers in Python (FastAPI, Flask) to expose ML models from Databricks to internal apps, CRM platforms, and AI agents at RBC. Work within the Data Science team to architect the serving layer, handling contract design, authentication, and documentation.

You’ll build and ship user-facing apps primarily on Databricks Apps, using React, Vue, or Angular, and integrate with REST/GraphQL APIs served by the Data Science team. You are the technical lead on a team migrating from Power BI to custom applications, owning the full lifecycle while mentoring engineers on DevOps practices like Git and CI/CD.

Proton★5.0 (1)· London

You will work with .NET, Windows desktop application development, multi-threaded programming, file systems, Git, GitLab CI/CD, and monitoring/alerting frameworks. You’ll build and maintain Proton Drive for Windows, a privacy-by-default application that manages local and remote state and performs cryptographic operations.

You'll work with the Natterbox platform including Voice AI Agents, Salesforce, telephony systems, and AI tools (LLM assistants, prompt-based workflows, internal AI agents). As a Solutions Engineer, you deliver technical wins in sales cycles by demonstrating the platform, designing solutions, and collaborating with Account Executives and partners.

You'll work with JavaScript, Node.js, Express, React, and MongoDB/Mongoose to set technical direction and oversee AI-assisted content-creation features. As Fractional Head of Product at StoryTerrace, you'll own the roadmap for two B2C platforms—an established product and a new self-serve app—directing one Full Stack Developer and advising on hiring. This role reports to the CEO and requires hands-on coding experience to unblock development.

JELLYFISH★3.5 (32)· London

The role focuses on building and extending an agentic delivery stack using tool APIs, MCP servers, AI harnesses, agentic operating systems, and Python. You will drive agentic delivery and adoption both inside Jellyfish, a global digital marketing agency, and with its enterprise clients. This is a 4-month fixed-term contract.

No specific technologies, languages, or tools listed. Moth builds tools for Entertainment, Media, and Creative industries, democratizing quantum computing for creators. The team is described as a small, dynamic, hands-on operations team.

JustPark★2.7 (6)· London

You’ll build agents/tools using Claude Code, working with Asana, Jira, Salesforce, Slack, Zendesk, Git, and APIs via Postman. You’ll partner with commercial, marketing, finance, operations, success, and support teams to map processes, automate workflows, and upskill internal teams. You’re a technical generalist solving high-autonomy, cross-department inefficiencies at a unified B2B/B2C parking platform.

Relay Technologies★2.0 (9)· London

At Relay Technologies you will build and own time-series forecasting models for parcel volume, inbound international volume, and parcel size/weight, using Python and ML frameworks. You will work on the Network squad’s demand-forecasting engine that predicts parcel movement across sortation, middle-mile, and last-mile operations, directly affecting cost per parcel. This is a hands-on individual-contributor role, serving as the technical anchor for Demand Forecasting, collaborating with a Senior Data Scientist, ML Engineer, and Analyst.

You will build with TypeScript, React, and SQL, using tools like GrowthBook, PostHog, LaunchDarkly, Statsig, Amplitude, Customer.io, and agentic coding tools such as Claude Code or Cursor. You'll join a small, senior engineering team at a seed-stage AI startup creating an AI employee that drafts client work for small businesses, owning the product's growth and activation funnel end-to-end.

Cognizant★3.8 (17k)· London

You will work with Python (FastAPI or Flask) in a serverless architecture, integrating with a NextJS/React frontend and third-party APIs. You will help build and enhance the NHS Digital Onboarding Service (DOS) for the NHS API Platform.

Meta★4.0 (1.1k)· London

Work with languages such as C++, Java, Swift, Kotlin, Python, JavaScript, and Hack to build and optimize user-facing applications across mobile and web. As a member of Meta’s product engineering teams, you’ll help advance its platforms—Facebook, Instagram, WhatsApp, and immersive AR/VR experiences—that connect billions globally.

TypeScript, React, Node.js (Bun where it fits), Kubernetes, and AWS. This Staff Engineer sets technical direction for the Financial Services team, building web apps, back office systems, and tooling that power financial product comparison.

Google★4.3 (6.2k)· London

Work with C++, Python, or Rust to build the Google Cloud Universal Ledger (GCUL), a payments platform addressing cost, speed, and fragmentation. Implement critical ledger capabilities including consensus, transaction dissemination, and data privacy via homomorphic cryptography and zero-knowledge proofs.

Sainsbury’s★3.5 (16k)· London

You will build and integrate server‑side logic for the Multichannel Messaging Hub, using Node.js, TypeScript, microservices, REST/JSON/SOAP APIs, Kafka, Snowflake, AWS serverless services, Kubernetes, and Terraform. The team of 7 engineers owns cross‑channel campaign delivery for Sainsbury’s brands.

Standard Chartered★4.1 (3.3k)· London

Senior developer role on Standard Chartered’s Blade platform (in-house pricing, execution, and trade processing) using JavaScript, TypeScript, React, Redux, RxJS, Webpack, CSS, HTML, Azure DevOps CI/CD, and preferably Java backend.

You'll work with Python, React, TypeScript, and AI coding agents across the full stack. TreasurySpring is a London fintech building a regulated Fixed-Term Fund platform that replaces manual institutional treasury processes and legacy systems with digital cash-management products for investors and corporations.

You will build and maintain server-side applications and APIs using Node.js, Python, Java, C#, PHP, and Ruby on Rails, working with MySQL, PostgreSQL, MongoDB, and cloud platforms AWS and Azure. You will join the development team to design scalable backend systems for the company’s web platforms, collaborating with front-end developers using Angular and React.

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.

You'll build GTM systems using HubSpot, DealHub, Gong, Clay, APIs, webhooks, Python, JS, SQL, and AI tools (ChatGPT, Claude, Copilot, Gemini, Notion AI). This role designs end-to-end systems—from lead enrichment and routing to quote-to-cash—for Monta’s EV charging platform, including prototyping AI agent workflows.

You will own Relay’s Demand Forecasting models, working hands-on with Python, ML frameworks, and forecasting tools to predict parcel volume, weight, and size at outcode granularity out to D30. You set the technical direction for the Network squad’s forecasting engine, which drives sortation, middle-mile, last-mile, and expansion decisions. The centralised data team has ~30 people, with you acting as the senior IC anchor, mentoring a Senior Data Scientist and an Analyst.

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.

Senior Scala engineer using Scala, Python, REST APIs, Solace, Couchbase, Gradle, Jenkins, Tekton, and OpenShift to build, maintain, and support an index calculation platform for the CIS business within Citi’s Equities Technology group.

You’ll build customer-facing treasury software using **Python, React and TypeScript**. You’ll own features end to end for TreasurySpring’s Fixed-Term Fund platform, which replaces manual cash-management processes and legacy systems for institutions.

Lead UI Developer role using TypeScript, React, RxJS, WebSockets/SSE, GraphQL, Protobuf, Flatbuffers, Jest/Vitest, React Testing Library, Playwright, and AG Grid. You will own the front-end architecture for a real-time Single Dealer Platform used by Sales, Trading, and institutional clients globally, building low-latency trading applications for market data, pricing, RFQ, and trade capture.