Stack Auth

Market position

The company positions itself as an open-source, developer-friendly alternative to incumbent authentication vendors such as Auth0, arguing that existing solutions are difficult to set up, priced unfavorably, poorly documented and prone to vendor lock-in, and that most alternatives address authentication only rather than authorization and user management. It has since broadened beyond auth into a wider set of user-facing modules including payments, emails and analytics.

Full open-source licensing with a self-hosting option alongside a managed cloud service; coverage of authorization, RBAC, multi-tenancy and user management rather than authentication alone; ready-made React components for common account flows; features such as impersonation, access token management and webhooks; and documentation surfaces built specifically for LLM coding agents, including an /ask endpoint and a full skill document.

Technology

The product ships SDKs for JavaScript/TypeScript (@hexclave/js), Next.js (@hexclave/next), React (@hexclave/react) and TanStack Start (@hexclave/tanstack-start), versioned together and largely feature-equivalent. The central abstraction is the Hexclave App object, split into a client-side app and a server-side app that requires a secret server key. A CLI (@hexclave/cli) injects project ID and secret server key environment variables into the development process and allows declarative configuration through a config file. Pre-built, customizable React components cover sign-in, sign-up, password reset, account settings and team management. A REST API allows integration from any backend or language, and webhooks are delivered via Svix. The self-hosted stack runs from a single Docker image backed by Postgres for core data and ClickHouse for analytics. The company also publishes LLM-oriented documentation surfaces, including a machine-readable documentation index, a full skill document and a question-answering endpoint intended for coding agents.

Go-to-market

Distribution is developer-led and open source: the codebase and examples are published on GitHub, documentation is public and structured for both humans and coding agents, and a Discord community provides support. The docs promote an agent-first setup path in which a setup prompt is pasted into a coding agent. The website offers a booking flow for calls with the team, and self-serve access runs through a cloud dashboard.

Developers and engineering teams building SaaS and B2B web applications, particularly those on JavaScript/TypeScript stacks such as Next.js, React and TanStack Start, including teams that need multi-tenant organizations, permissions and RBAC, and organizations that prefer to self-host their user infrastructure.

Geography

Headquartered in San Francisco, with founding roots at ETH Zurich in Switzerland.

History

The company was founded in 2024 and participated in Y Combinator's Summer 2024 batch, launching publicly as Stack Auth, an open-source user authentication product with built-in authorization and user management. It was also listed as an active open-source software engineering project at ETH Zurich's Student Project House. The product has since been rebranded to Hexclave and expanded from authentication into a broader modular user platform, while the original stack-auth.com and docs.stack-auth.com domains and the stackauth/server Docker image remain in use.