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.

Work with Python, FastAPI, Docker, DuckDB, JSON Schema and Git to design, build and ship client ETL pipelines that map raw bank data onto the FIRE regulatory reporting standard. You will maintain a shared ETL framework, write validated mapping code, and mentor junior engineers at Suade, a regtech SaaS company automating compliance for financial institutions.

You'll design and own end-to-end RAG pipelines for payments domain content using Python, Azure Data Factory, Functions, ADLS, CosmosDB, and AI Search, with CI/CD via GitHub Actions and Azure DevOps. RedCompass Labs builds AI-powered payment transformation and financial crime detection solutions, including the RedFlag Accelerator for identifying human trafficking. You'll collaborate with AI engineers and payments experts to turn regulatory documents and handbooks into a reliable retrieval layer for their proprietary multi-agent AI platform.

Build enterprise-grade web applications using Python (Django/FastAPI), React, TypeScript, and PostgreSQL. Develop RESTful APIs, responsive UI components, and contribute to system design, CI/CD pipelines, and performance optimization.

You’ll work with Python (Django/FastAPI), React, TypeScript, PostgreSQL, REST APIs, and CI/CD. You’ll own end-to-end feature delivery on scalable, enterprise-grade web applications.

Python micro-services with RabbitMQ and OpenShift/Kubernetes, using SQL Server and Parquet. The London Commodities Risk Technology team builds a front-office distributed platform for trading and risk calculations on assets like oil, gas, power, and exotics, collaborating with traders and quants.

Work with C# on .Net Framework 4.5.2+ and .Net 5+, using NUnit, xUnit, REST, Kafka/RabbitMQ, Git, and Linux. You will build Citi’s next-generation Equities technology platform for execution, clearing, and margin processes.

Working with Core Python, Pandas, NumPy, Flask/FastAPI/Django, SQL, and Unix/Linux, you will build backend applications and data processing pipelines for trading and risk management within an investment banking environment, supporting risk calculations, trade workflows, and reporting.

HSBC★4.0 (16k)· London

Work with Python, Docker, Kubernetes, Flask/FastAPI, PyTorch/TensorFlow, SQL Server/Postgres, and CI/CD pipelines to build and deploy production-grade ML and GenAI services. You will join the Growth AI programme within HSBC’s Corporate & Institutional Banking Data & Analytics, developing AI applications to identify business opportunities and mitigate client attrition.

You'll work with FastAPI, TypeScript, React, OpenAI/Anthropic, PostgreSQL, and Azure to build AI agent systems—from voice interfaces to workflow orchestration—for aircraft maintenance and manufacturing. Fleetcraft builds infrastructure that helps technicians maintain and manufacture aircraft.

You will build and maintain Python services using FastAPI and Azure Functions, design and consume REST APIs, work with MS SQL Server, and leverage Azure infrastructure. The team delivers a loan management platform for a global financial services firm, handling complex servicing workflows in a regulated environment.

Edited★2.7 (3)· London

You will work with Python, *nix, LLMs, MCP, Django, Flask, FastAPI, Elasticsearch, and SQL databases. You will build an AI chatbot with agents and tooling, and scale a large-scale retail data infrastructure on AWS and bare metal for the company's AI-driven retail intelligence platform.

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.

Cboe Global Markets★3.7 (14)· London

You'll work primarily with Python to design and build highly reliable trading systems, working closely with advanced SQL, Linux, and optionally PostgreSQL, Snowflake, Apache Kafka, Apache Airflow, Django, Flask, or FastAPI. You'll expand data pipeline and event streaming functionality for Europe's largest equities exchange and related platforms, while leading complex projects, mentoring developers across multiple global teams, and participating in production support for Cboe Europe's trading operations.

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.

EXL Service★3.7 (2k)· London

You will work with Python, FastAPI, LLM frameworks (prompt engineering, RAG, agentic systems), and cloud AI platforms (Azure OpenAI/AWS Bedrock/Claude) on Kubernetes. As a Sr. AI Architect & Client Partner at EXL, a data and AI services company, you will design and deliver production-grade Generative and Agentic AI systems for enterprise clients, converting ambiguous mandates into secure, scalable solutions while shaping deals and reusable IP.

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.

A full-stack or backend specialist will use C# and .NET Framework, SQL Server (T-SQL), RESTful APIs, Azure DevOps, and messaging queues (RabbitMQ, Kafka) to build secure integration pipelines and backend services. They will execute a critical integration programme for an international Wealth Management firm to connect core internal and third-party systems.

Senior Python Developer role building trading and risk platforms using Python, SQL, Pandas, NumPy, Flask/FastAPI/Django, PySpark, Unix/Linux shell scripting, and enterprise platforms like Quartz or SecDB. The team develops backend services, data pipelines, and risk applications for trade lifecycle, risk calculations, and regulatory reporting within investment banking.

Lead a team of 8 senior engineers using React, TypeScript, Python, FastAPI, Dagster, dbt, Snowflake, and AWS. The company fuses fragmented UK transport data into an operational intelligence layer for councils and highways authorities. This role includes architectural ownership and a path to CTO as the team scales toward 20-30 engineers.

As a Backend Software Engineer, you'll use Go or Node.js to build and scale the company's core real-time messaging platform, working on low-latency Pub/Sub services and state synchronization in an AI-first engineering environment.

Full Stack Developer role using Python, FastAPI, React, Docker, AWS, PostgreSQL, NodeJS, JavaScript, TypeScript, CI/CD, and unit testing. The developer will work on the company’s products. No team size or project scope is specified.

JavaScript and Vue.js for component-based UIs, Python with FastAPI for Lambda endpoints, PostgreSQL for schema design, and AWS (Lambda, API Gateway, S3). The role involves feature development and redesign of core tools using Vue.js, AWS Lambda, and Aurora PostgreSQL, plus building the backend API layer.

Python, FastAPI, PostgreSQL, GCP, Docker, Terraform. The team builds Scenario Builder, a platform for energy-system modelling, grid planning and decarbonisation analysis. You will lead a hands-on squad of 3–5 engineers, staying close to the code while setting technical direction.