GuantrFlexible, type-safe

JavaScript library for efficient authorization and permission checking

Type-safe

Misspelled an action? Wrong field in a condition? TypeScript catches it before your code runs.

eq, and, some, contains — 17 operators with operand types enforced at compile time.

Conditions become plain JSON. Store them wherever you want — database, config file, edge KV.

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Node, Deno, Bun, edge, browser. No opinions on your server or framework.

Adapters for SQLite, PostgreSQL, Prisma, Drizzle — or write your own.

Unconditional denies short-circuit. Conditional denies override allows. Simple, predictable.