A Senior Full Stack Developer is needed to work with Angular, .NET, and legacy ASP.NET MVC. The role involves developing, enhancing, and modernising business-critical Front Office applications for an Investment Bank.

Teksystems★3.8 (4.7k)· London

You will work with Java (Spring Boot) and Angular to enhance and maintain a large-scale customer relationship management platform for a Tier 1 banking client.

Design and deploy AI applications across the full stack using modern AI frameworks and LLMs. You will join a dedicated team at the heart of a leading global financial organisation’s AI function.

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.

You will build evaluation, experimentation, and observability pipelines using Python and platforms like Braintrust, LangSmith, Arize, and Weights & Biases, plus design LLM-as-judge and human-in-the-loop scoring. The role focuses on AI-native consulting for clients like PayPal and adidas, including production monitoring, quality signal detection, and cost attribution. You'll also wire evaluation gates into CI/CD pipelines for the AI Engineering team.

Build, run, and evolve the API gateway and routing layer connecting engineers and client workloads to multiple LLM providers (Anthropic, AWS Bedrock, OpenAI), including failover and routing strategies, using Python or Go. The team also designs orchestration and lifecycle management for AI capabilities and implements RBAC/OIDC access controls. This is a role within CreateFuture, an AI-native consulting partner building digital products for clients.

You'll work with Kubernetes, Terraform, Python, AWS or GCP, and CI/CD tools (GitHub Actions, GitLab CI, Argo CD), plus observability stacks (Datadog, Prometheus, Grafana). You'll bring SRE discipline to an AI platform hosting model serving, agent orchestration, and batch inference.

Build and run the API gateway and routing layer connecting workloads to Anthropic, AWS Bedrock, and OpenAI using Python or Go, Kong or Envoy, and RBAC/OIDC. The team creates the infrastructure and orchestration tooling that turns AI integrations into a reusable "capability marketplace" with governance controls. Senior engineers own delivery of key platform components from the gateway through orchestration.

You will work with Python or Go, API gateways (Kong, Envoy, or Apigee), multiple LLM providers (Anthropic, AWS Bedrock, OpenAI), RBAC/OIDC, and MCP or service-registry patterns. As part of the AI Platform Engineering team, you will build and run the infrastructure—API gateway, orchestration tooling, and governance controls—that connects engineers and client workloads to LLM providers. In this Principal role, you set technical direction for the platform and act as a trusted extension of CreateFuture’s leadership.

Worldpay★3.0 (53)· London

You'll design secure checkout APIs (UCP, ACP, AP2, Agentic Tokens, MPP) and SDKs, integrating AI agents and LLMs across Global Payments platforms. This greenfield team builds autonomous commerce infrastructure, defining how AI agents transact securely on behalf of consumers.

Lead Software Engineers use TypeScript, Java, Golang, Rust, Python; deploy on Kubernetes and Google Cloud; and work with BigQuery, REST, and observability tools. They build and scale supplier integration, search/recommendation, real-time pricing, ML marketing, booking/payment/fulfillment, and AI-powered systems for the company’s packaged-holiday platform.

Thomson Reuters★3.9 (4.3k)· London

Work with Java and Python across containerized services, relational databases, and distributed systems, including AI/LLM integration patterns. As a Principal Engineer on Thomson Reuters' HighQ, an enterprise collaboration platform for law firms, you will set technical direction, architect scalable systems, and lead the integration of AI and agent platforms.

Amazon★3.5 (56k)· London

This role involves designing and building scalable security systems, with development in Java, C++, or C#. You’ll automate pentest processes and create a greenfield product that provides critical security details about Amazon applications, working with teams across the company. The position involves owning architecture, design, and reliability for new and existing systems.

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.

Blockchain★3.4 (14)· London

Lead a small engineering team building crypto savings and crypto-backed lending products at Blockchain, using Kotlin or Java, Kafka, PostgreSQL, and Redis. You will define technical architecture, design distributed systems, and drive best practices in a hands-on role.

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.