20 of 20 Permanent Open Source Jobs in the City of London

Product Engineer

Hiring Organisation
WireMock
Location
City Of London, England, United Kingdom
Company Description WireMock is the industry standard for API environment simulation. With a massive global open-source footprint and deep adoption across the Fortune 500, we provide the critical infrastructure that engineering teams use to de-couple development from fragile dependencies. As AI agents and LLM-integrated apps … function without them where necessary. Cares about user delight over technical purity. Writes code in Java, Kotlin and ideally Javascript. Enjoys contributing to open source, including writing and speaking. Proactively improves their own skills and understanding of the domain they’re working in Salary range £80k-110k. Java ...

Senior Full Stack Engineer

Hiring Organisation
Prolo
Location
City of London, London, United Kingdom
analysis using Python (pandas, numpy) Understanding of data pipelines and ETL processes AI/LLM Engineering Experience integrating LLM APIs (OpenAI, Anthropic, Gemini, or open-source equivalents) into production applications Understanding of core LLM concepts: context windows, token limits, temperature, system prompts, and model selection trade-offs Experience … Experience building scalable backend systems Ability to work across multiple domains (backend, DevOps, data) Examples of taking projects from idea to production Contributions to open source or personal projects Note : Prolo is a startup with a small engineering team, which means you'll be expected to be versatile ...

Full Stack Software Engineer

Hiring Organisation
83zero Ltd
Location
City, London, United Kingdom
Employment Type
Permanent
Salary
GBP 100,000 - 130,000 Annual
architecture. In this role, you will empower the business with the technology and tools needed to leverage data throughout the organization. This Includes: Deploying open-source BI tools and platforms Setting up streaming data collection and validation services Implementing third-party analytic solutions Assisting with data-centric migration … implement solutions with minimal supervision Experience building internal-facing CRUD applications Familiarity with front-end development and ability to make basic modifications to open-source UI components Experience enabling data scientists and engineers with Python-based development workflows and tooling Technology Stack: Azure Cloud Services C# (.NET ...

Full Stack Engineer

Hiring Organisation
Prolo
Location
City of London, London, United Kingdom
analysis using Python (pandas, numpy) Understanding of data pipelines and ETL processes AI/LLM Engineering Experience integrating LLM APIs (OpenAI, Anthropic, Gemini, or open-source equivalents) into production applications Understanding of core LLM concepts: context windows, token limits, temperature, system prompts, and model selection trade-offs Experience ...

Global Banking & Markets - Software Engineer - Vice President - London

Hiring Organisation
Jobleads-UK
Location
City Of London, England, United Kingdom
reconciliation, and multi‐system migration environments. Other: Asynchronous/non‐blocking I/O frameworks (e.g., Vert.x, Netty), multi‐region/BCP architectures, and opensource contribution experience. ABOUT GOLDMAN SACHS At Goldman Sachs, we commit our people, capital and ideas to help our clients, shareholders ...

AI Native Software Engineer

Hiring Organisation
TekWissen UK
Location
City of London, London, United Kingdom
fault‐tolerant deployments Collaboration Tools or Platforms Microsoft Office (Excel, Word, Outlook, Teams) AI Platforms & Models: OpenAI, Anthropic (Claude), Google Vertex AI, and select opensource models Agent & Orchestration Frameworks: LangGraph, AutoGen, CrewAI (or similar) Cloud & DevOps Tooling: Docker, Kubernetes, Terraform, Helm, CI/CD pipelines Enterprise Integration ...

Staff Software Engineer

Hiring Organisation
ShareChat
Location
City of London, London, United Kingdom
large-scale models using tools such as Tensorflow or PyTorch is a plus. You stay up-to-date with the state-of-the-art open source infrastructure solutions applicable to designing and improving large scale recommender systems, data engineering, and machine learning You have a Master ...

AI Engineer [Computer Vision]

Hiring Organisation
Depixen
Location
City of London, London, United Kingdom
relevant field. Experience implementing or fine-tuning vision-language models such as CLIP, BLIP, or SAM. Experience with multimodal AI, visual grounding, open-vocabulary detection, or image-text retrieval. Familiarity with edge deployment frameworks such as TensorRT, OpenVINO, or ONNX Runtime. Experience with 3D vision, point clouds, depth estimation … technical document analysis, or product data systems. Experience with OCR, technical document processing, drawing analysis, catalogue data extraction, or visual product matching. Contributions to open-source computer vision projects. Experience deploying models on cloud platforms such as AWS, GCP, or Azure. Experience with data annotation, synthetic data, active ...

Senior Site Reliability Engineer

Hiring Organisation
Realm
Location
City of London, London, United Kingdom
Hands-on experience with data centre or bare-metal infrastructure Knowledge of high-performance networking technologies Experience managing large-scale storage systems (commercial or open-source) Compensation & Benefits Competitive salary and equity package Retirement or pension contributions aligned with local standards Health coverage including medical, dental, and vision ...

Kubernetes Linux AIOps Engineer – Elite Quant Hedge Fund

Hiring Organisation
Winston Fox
Location
City of London, London, United Kingdom
write high quality Automation/scripts from scratch. Configuration Management Tools (Ansible/Puppet/Kapitan/Terraform....) Observability: Experience within the modern open-source ecosystem (ELK, OpenTelemetry, LGTM stack, Prometheus, Grafana, Loki...) CI/CD and GitLab/GitOps : working with Development teams. A track-record ...

IT Integration Developer

Hiring Organisation
Profectus Recruitment
Location
City of London, London, England, United Kingdom
Employment Type
Full-Time
Salary
£70,000 - £80,000 per annum, Inc benefits
programmes • Experience working alongside AI, Automation or Power Platform teams • Background in software development with the ability to work with internal codebases • PHP or open source framework experience would be beneficial • Microsoft Azure certifications would be advantageous Why Apply? This is an opportunity to join a forward thinking ...

Senior Backend Engineer

Hiring Organisation
Nelly Works
Location
City of London, London, United Kingdom
powered features is valuable but not required. End-to-end ownership mindset : You've shipped something meaningful on your own—a project, open source tool, or business—and you drive work from conception to production. Modern backend fundamentals : Comfortable with modern backend languages and frameworks, plus exposure ...

Mid-Senior Ruby on Rails Engineer (B2B SaaS | Hybrid | UK)

Hiring Organisation
Transreport
Location
City of London, London, United Kingdom
Experience working with mobile applications (React Native/Kotlin/Swift). Experience working in regulated industries or multi-client B2B systems. Contributions to open-source Ruby projects or technical blogging. Benefits Private healthcare after your probation (including children) Hybrid working model 25 days holiday Volunteering Leave Free ...

Engineering Manager

Hiring Organisation
Canada Life UK
Location
City of London, London, United Kingdom
Employment Type
Part Time
optimise flow, deliver customer value and modernise our platforms. Our bespoke mortgage system is built using Ruby on Rails, MySQL, JavaScript, and other open-source technologies, with a clear roadmap toward cloud-native evolution. Key responsibilities Lead, coach and inspire a stream-aligned product engineering team, fostering ...

Java Engineers - Senior / Lead

Hiring Organisation
numi
Location
City of London, London, United Kingdom
standards and a commitment to building trust-based software. Nice to Have Previous experience in a fintech or high-growth startup environment. Contributions to open-source projects or a background in building custom tooling. Familiarity with cross-functional "tribe and squad" working models. Why Join ...

Principal AI Engineer

Hiring Organisation
Jobleads-UK
Location
City Of London, England, United Kingdom
follow through Value collaboration, openness, and continuous improvement Bonus points if you’ve worked with APIs, cloud-native platforms, AI-enabled systems, or open source, but curiosity matters most. Life at Gravitee At Gravitee, we invest in humans, not just roles. You’ll get: Competitive medical coverage Pension ...

Lead Software Engineer

Hiring Organisation
Understanding Recruitment
Location
City of London, London, United Kingdom
Employment Type
Permanent
Enhance overall system efficiency, expandability, and dependability within distributed robotic setups. Experience you'll need: Production experience with Rust , or contributions to production grade open source repos. 2+ Years. Experience working with Tokio , or other asynchronous frameworks such as async.std or Smol. Ideally a background in a core ...

Member of Technical Staff

Hiring Organisation
Geometric
Location
City of London, London, United Kingdom
Deep Learning, Category Theory, Neuroevolution, Megakernels, or the work of François Chollet, Kenneth Stanley, Jeff Clune, Jurgen Schmidhuber, David Ha, and Christian Szegedy Bonus Open-source kernel contributions (FlashAttention, FlashInfer, vLLM, Unsloth, Liger-Kernels, ThunderKittens) Publications in ML/AI, kernel optimisation or evolutionary methods (NeurIPS, ICLR, CVPR ...

Backend Engineer

Hiring Organisation
Neulinx
Location
City of London, London, United Kingdom
first software Exposure to Cloudflare, real-time databases, or collaborative application backends Experience building infrastructure for products serving both end users and developer customers Open-source contributions or involvement in developer communities What’s on offer £90,000 - £130,000 salary Equity options Hybrid working ...

Forward Deployed AI Operators

Hiring Organisation
SilverTree Equity
Location
City of London, London, United Kingdom
faster. Successful FDEs are: Scrappy. Curious. Action-oriented. Resilient. Ownership-driven. Whether that mindset shows up through side projects, community builds, freelance hacks, competitions, open-source contributions, or experimentation, we're interested in how you can think, learn, and build. Programme: Built Upon a Dual Structure FDEs will … their first few years at a traditional firm. Fully-formed FDEs have: Deep, real-world AI experience An impressive portfolio of shipped impact Open doors to future strategic and leadership roles ...