Oso

Market position

Oso describes itself as the creator of the externalized application authorization category and, as of its 2022 funding announcement, as the best-capitalized authorization company in the world. Its investor roster includes Sequoia Capital, Felicis and Harpoon Ventures plus a large group of infrastructure and developer-tool founders. Named users of the applications product include Intercom, Wayfair, Productboard, Duolingo, Oyster HR, Chief, Arc, Audiostack, Olive AI and Digimarc; endorsements for the agent product come from executives at Roblox, Clay, Brex, Spring Health and 1Password.

Oso positions itself on singular focus on authorization and on the flexibility of Polar, its purpose-built declarative policy language, which customers cite as allowing custom authorization models to be defined quickly. For the applications product it emphasizes batteries-included primitives for common patterns (admin roles, sharing, list filtering), idiomatic SDKs across six languages, developer tooling for testing and debugging, extensive documentation, and a Rust implementation tuned for latency and uptime. For agents, it frames its edge as seven years of experience building human permissions systems informing an "automated least privilege" approach that narrows agent permissions dynamically based on prior agent behavior, rather than relying on prompt-level safety.

Technology

Core technology is an authorization engine written in Rust with a WebAssembly build for the Node.js library, exposed through Polar, a declarative DSL for expressing permission logic. The open source framework provides modeling primitives for RBAC and relationship-based access, list filtering ("which records can this user see"), unit testing, a debugger and REPL, and libraries for Node.js, Python, Go, Rust, Ruby and Java. Oso Cloud adds a hosted multi-region service, visual rules editor, VS Code extension, Explain debugging and logging. The agent platform captures prompts, tool calls and responses, applies default detections (rule violations, high-velocity behavior, PII leakage, API key exposure) and user-defined policy rules, and produces exportable audit logs.

Go-to-market

Two motions run in parallel. The agent security product is marketed via "book a demo" and enterprise outreach, supported by research reports, press coverage, executive testimonials from security and engineering leaders, and thought-leadership content. The applications product uses a developer-led motion: a free trial, extensive documentation, the Authorization Academy guide series, an open source library and community Slack, and "meet an engineer" contact paths. The company has also used co-marketing with partners such as Cyera and Tailscale.

Engineering and security teams at software companies deploying fine-grained application authorization, and enterprises whose engineering, product, finance and sales functions are adopting AI agents. Cited users span developer tools, fintech, e-commerce, healthcare and consumer software.

Geography

Oso is a distributed team headquartered in the NoMad neighborhood of New York City, with regular hybrid days for staff in the area. Its cloud service is described as running across 30+ availability zones and multiple regions.

History

Oso began as an authorization company for application developers, building an open source authorization framework with libraries for Node.js, Python, Go, Rust, Ruby and Java, and a Rust core with a declarative policy language called Polar. By 2022 the team had been working on roles and permissions for 3+ years and had launched Oso Cloud, its hosted authorization service, with customers including Chief, Arc, Intercom, Wayfair, Productboard, Olive AI and Digimarc. Alongside a $15M round it added learning resources and product capabilities and hired a Head of Marketing from Snyk. The legacy open source Oso library was subsequently deprecated, with the company signaling a future open source release. By 2026 Oso described itself as having spent seven years building permissions for humans and had extended into AI agent security, publishing joint research with Cyera on unused permissions, maintaining the Agents Gone Rogue registry, and working with Tailscale on controls for coding agents.

Risks & controversies

The legacy open source Oso library has been deprecated, which the company says is not an end-of-life but leaves the community awaiting a future open source release. The company's agent security positioning depends on enterprises adopting new controls for rapidly changing agent tooling; its own blog documents systemic risks in this area (prompt injection, memory poisoning, exposed agent control planes, over-broad credentials). No controversies involving Oso itself are reported in the sources.