Best Open Source Companies in London, United Kingdom
The 49 best Open Source companies in London, United Kingdom in 2026, ranked by funding and momentum. Funding, investors, founders, valuation, tech stack and live signals. Top: Stability AI.
Ranked: Best Open Source companies in London
| # | Company | Last round | Disclosed funding | Employees | Founded | Founder | Tech stack | Patents & IP focus | Recent signals |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Activiti Cloud-based software for business process automation | — | — | 123 | 2010 | John Newton Co-Founder & CTO | VarnishGitHub PagesAzure+6 | — | — |
| 2 | Ankyra Provider of open source release engineering toolset | — | — | 1 | 2016 | Bart Spaans Founder & CEO | — | — | — |
| 3 | Chronicle Accelerate Open source blockchain framework for monetary transactions | — | — | — | 2017 | Peter Lawrey CEO | — | — | — |
| 4 | Citeck Offers open source digital business platform | — | — | — | 2010 | Anton Ivanov CEO | — | — | — |
| 5 | Coposition Platform for location data creation, storage, and management | — | — | — | 2015 | Patrick Wills Co-Founder | — | — | — |
| 6 | Countly Mobile application analytics | — | — | 30 | 2012 | Osman Koycu Co-Founder & Designer | — | — | 2 launchs · 1 partnership |
| 7 | DBVu Centralised MySQL monitoring | — | — | 2 | 2010 | Andy Robinson CEO | — | — | — |
| 8 | Facetflow Hosted Elasticsearch | — | — | — | 2011 | Mattias Nordberg Founder | — | — | — |
Top 12 Open Source companies in London
#1
Series C · London, England · founded 2013 · 14 employees$101.4Mraised▾
Balena, fka Resin, is a provider of an infrastructure needed to develop, deploy, and manage fleets of connected devices at scale. Its chief offering is balenaCloud which is a container-based platform for deploying IoT applications. In addition, the ecosystem comprises of balenaOS which is an operating system tailored for containers, balenaEtcher which is an open source tool to make device provisioning easy and to flash balenaOS images on the devices, balenaFin which is a carrier board for the Raspberry Pi module and comes with reliable storage, industrial power, flexible networking, real-time and low-power capabilities, among others. As of November 2018, the pricing of the platform starts at $99 per month. Clientele includes Intale, Pact, Enerbrain, Sense, TAPP, Open Energi, among others.
- Jan 2026Series C—
- Sep 2019Series B$53.6M
- Jul 2019Series B$21.1M
- Jun 2018Series B$5M
#2
Series A · London, England · founded 2021 · 3 employees$26Mraised▾
Developer of a multi-model database for AI agents and applications. The database unifies document, graph, time-series, relational, geospatial, and key-value data models. It offers integrated search and retrieval capabilities, including vector, full-text, and hybrid search. The platform provides real-time subscriptions, event triggers, and streaming updates. It also features built-in security with access controls and compliance.
- Feb 2026Series A$23M
- Jun 2024Series A$20M
- Nov 2022Seed$6M
#3
Series A · London, England · founded 2017$10.8Mraised▾
Provider of open source API platform for financial services. The company offers strategic imperative for all banks and financial institutions, open banking APIs for management of the API platform, and standard-based API’s that can handle the complexity of open banking.
- Nov 2025Series A—
- Dec 2023Series A$11.7M
#4
Seed · London, England · founded 2020 · 1 employees$6Mraised▾
Cloud based application development and deployment solution. It enables users to develop and deploy applications using the Rust framework. It provides infrastructure definitions from code function signatures and annotations to build the backend. It connects with databases to develop a URL shortener.
- Oct 2025Seed$6M
#5
Seed · London, England · founded 2021 · 45 employees$206Mraised▾
Developer of generative AI models for image, video, audio, and 3D. These models are designed for deployment across various platforms, including self-hosted, licensed, API, and cloud-based services. The company provides tools for marketing, entertainment, and gaming, focusing on customizable workflows and enterprise-level solutions. It offers resources such as a learning hub and customer stories to support users.
- Jun 2024Seed$80M
- Jun 2023Seed—
- Sep 2022Seed$101M
#6
Series C · London, England · founded 2014 · 22 employees$40.8Mraised▾
Tyk is an API management platform that consists of an open source API gateway, analytics unit, dashboard and a developer platform. The dashboard allows the user to maintain, manage, promote, and protect APIs using the gateway combined. It comes with built-in analytics tool for providing the user with actionable information about how the API is being consumed. The company claims that their gateway is capable of handling approximately 2,000 requests per second with sub 85ms latency. The platform can be deployed on premises, hosted on the cloud, or offered as a hybrid solution.
- May 2024Series C—
- Sep 2021Series C$35M
- Apr 2019Series A$5M
- Feb 2017Seed$670K
#7
Series A · London, England · founded 2019 · 31 employees$12.5Mraised▾
Developer of knowledge graph software for structured data management automation. The platform integrates information from various sources to create self-maintaining knowledge graphs. It provides tools for mapping processes, automating workflows, and enabling agentic artificial intelligence. The system supports data synchronization, granular access permissions, and provenance tracking for information. It allows third-party artificial intelligence assistants to query connected data while maintaining privacy and security protocols. The software facilitates retrieval augmented generation and provides audit capabilities for business operations.
- Jul 2024Series A$10M
- Jun 2020Seed$2.5M
#8
Acquired · London, England · founded 2009 · 61 employees$74.9Mraised▾
Platform that provides SaaS based solutions for derivatives risk analytics. It provides an open source platform for derivatives risk management and analytics to the financial services industry, for use in the derivatives OTC markets. The company refers to its solutions as risk service and its products cover ETD & OTC margin calculations, bilateral OTC margining, and derivatives.
- Feb 2022Series E$21M
- Apr 2019Series D$10M
- Jan 2017Series D$1M
- Oct 2016Series D$13.3M
#9
Series B · London, England · founded 2016 · 128 employees$52.3Mraised▾
Decentralized team messaging app for enterprises. Its app also allows users to share photos and files and provides end to end messaging solutions for enterprises. Its mobile app is available for both iOS and Android devices and a web app for Windows and macOS. It allows users to communicate securely and collaborate in real time, making it suitable for businesses and organizations that prioritize data sovereignty and security.
- Jul 2021Series B$30M
- Apr 2020Series A$4.6M
- Sep 2019Series A$8.5M
- Jan 2018Seed$5M
#10
Seed · London, England · founded 2021 · 8 employees$7.1Mraised▾
Developer of a framework for building internal developer platforms. The framework enables co-creation of platform capabilities tailored to an organization's needs. It provides a contract between application and platform teams through the creation of promises. The framework offers workflows to codify organizational policy, compliance, and governance, enabling consistent application. It also simplifies operations across different environments and clusters.
- Oct 2023Seed—
- Oct 2023Seed—
- Oct 2023Seed—
- Oct 2023Seed—
#11
Deadpooled · London, England · founded 2014 · 95 employees$56.6Mraised▾
Weaveworks offers enterprise Kubernetes and application management based on GitOps. The company offers Weave Kubernetes Platform to accelerate cluster delivery and security with GitOps workflows. It enables users to spin up clusters on-demand for production applications on upstream open source or cloud-managed Kubernetes. The solution is offered both in the cloud and on-premise.
- Oct 2020Series C$36.6M
- May 2016Series B$15M
- Dec 2014Series A$5M
#12
Acquired · London, England · founded 2023 · 2 employees$2.5Mraised▾
Open source based application deployment platform. It allows developers to build and deploy real-time multiplayer collaborative applications, games, and websites. The platform offers tools such as analytics, secrets management, and staging environment to build the applications.
- Sep 2023Seed$2.5M
Funding & investor landscape
Notable founders
Market landscape — 10 sub-themes by coverage
Share of Open Source coverage by sub-theme.
Regulatory-risk over time rising
Funding & growth over time
funding rising · growth rising
Common questions
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