About
Cosine builds an AI software engineering agent for production software teams. Its agent works across CLI, cloud, and desktop to understand codebases, plan and implement changes, test code, and coordinate parallel tasks, differentiating it through end-to-end autonomous workflows and multi-surface continuity.
Market
Cosine competes in the AI coding-agent and AI-native software-engineering market, positioning itself as an AI engineer for production software teams rather than merely a code-completion assistant. It differentiates through maintainability-focused models, real engineering workflows, visibility and control across CLI, desktop, and cloud, plus private and air-gapped deployment options for regulated organisations.
Cosine targets professional engineering teams across finance, defence, SaaS, and manufacturing, ranging from startups to global enterprises. Its strongest fit is for engineering leaders and security-conscious organisations with complex, high-security, regulated, or air-gapped codebases.
At a Glance
Problem
Software teams need to change large, messy, long-lived codebases without sacrificing architecture, maintainability, visibility, or control. Cosine targets the gap between simple AI autocomplete and the harder work of understanding an existing system, investigating a problem, planning a change, implementing it, reviewing the result, and correcting mistakes. The pain is costly engineering time and the downstream burden of AI-generated “slop”: code that may be fast to produce but is harder to maintain and review.
The killer use case is autonomous or collaborative work on real software tickets, especially debugging, feature development, refactoring, and other open-ended changes. The economic promise is higher production throughput with fewer headaches and less rework, rather than merely generating more lines of code.
Product / Service
Cosine is an AI software-engineering system built around its Lumen model family. Lumen is specialized for production software and maintainable code, while Cosine provides one underlying agent across a terminal-native CLI, a desktop application, and a cloud platform. Developers can work locally with external tools and multi-agent orchestration, use the desktop app to plan and steer longer tasks, or delegate work to remote agents when they need more parallelism or continuity across devices.
The cloud runs parallel agents in isolated MicroVMs and worktrees, producing independent diffs that do not merge until a developer reviews them. Teams can use Cosine-managed models or bring their own keys, and enterprise customers can choose managed cloud, dedicated, VPC, private-cloud, on-premises, or air-gapped deployment. The commercial model is a flat-rate, pay-per-task subscription represented through monthly credits, with published plans starting at $19 per month for individuals, $199 for teams, and $999 for enterprise, while Cosine says it does not train on customer data without explicit approval.
Market
Cosine competes in the AI software-engineering and autonomous coding-agent market, alongside products such as Cognition’s Devin and Amazon Q Developer, with adjacent competition from Cursor, Claude Code, OpenAI Codex, and GitHub Copilot. Its differentiation is an opinionated, vertically integrated agent experience focused on longer-running, multi-threaded work in real repositories, maintainable output, developer control, and deployment flexibility rather than only IDE autocomplete.
Cosine is not presented as pre-revenue: it has public pricing, a free entry plan, and an enterprise offering, and its FAQ says the product is used by teams in finance, defence, SaaS, and manufacturing, including global enterprises with air-gapped systems. Public traction includes YC Winter 2023 and an active company listing, a 2024 seed round reported at approximately €2.2 million or $2.5 million, a reported 30% SWE-Bench result at launch, and a later profile reporting $6 million raised. In 2026, Cosine also announced a coalition of major UK organisations to co-design Lumen Sovereign under the government’s Sovereign AI programme. The evidence does not disclose ARR, revenue, or customer counts, so commercial availability and enterprise signals are clearer than demonstrated revenue scale.
Founders & Leadership
Funding History
Not disclosed
Y Combinator
UpHonest Capital, SOMA Capital
Not disclosed
Recent News
Cosine analyzed the cost-effectiveness of air-gapped, sovereign GPU deployments versus cloud-based coding agents, focusing on enterprise AI spending and deployment economics.
In an interview with Cosine co-founder and COO Yang Li, Resilience Media examined sovereign and air-gapped AI. The discussion also covered how customers can fine-tune and post-train models using their own data.
The Telegraph profiled Cosine's effort to build UK-based AI, presenting it as a potential answer to dependence on powerful foreign AI models, including Anthropic's systems.
City A.M. reported that Cosine's proposed UK-built Lumen Sovereign model had secured blue-chip backing. The announcement coincided with the UK government’s push for sovereign compute and AI capability.
Cosine announced a coalition including BAE Systems, Babcock, BT, HSBC, Leonardo, Lloyds Banking Group, LSEG, NatWest, PwC, Telefónica Tech UK&I, Thales UK, and The Alan Turing Institute to co-design Lumen Sovereign. The participants signed an MoU covering use cases, security protocols, and governance for a sovereign frontier model.
Innovation News Network covered Cosine's coalition to develop a sovereign frontier model running exclusively on Isambard-AI. The participating companies signed MoUs on technical requirements, governance, and applications, with deployment readiness targeted by the end of 2026.
Fintech Futures reported that HSBC, Lloyds, and NatWest joined Cosine's coalition to co-design Britain's first frontier AI model under the UK government's £500 million Sovereign AI programme.
The Next Web covered Cosine's effort to build a sovereign AI model with major UK companies, emphasizing procurement and security needs for banks, defence firms, and critical infrastructure. The model is intended for customer-controlled and air-gapped deployment, with completion targeted for the end of 2026.
Cosine announced an air-gapped deployment approach allowing agentic software engineering to operate inside isolated environments without source code, prompts, outputs, or model activity leaving the security boundary.
Cosine launched Lumen Outpost, a targeted post-trained coding model designed to reduce low-quality code, improve behavior, and perform better in niche languages. The model became available through Cosine surfaces, with custom deployment offered for enterprises.
Active Roles
3Business Model
Cosine sells subscription plans priced by monthly access and included Cosine credits, with additional credits available for purchase. It also offers higher-priced enterprise plans and customized deployment options, including managed single-tenant and air-gapped environments.