Ajv JSON Schema Validator

Ajv is the fastest JSON Schema validator for Node.js and browser, supporting JSON Schema drafts 04/06/07/2019-09/2020-12 (draft-04 requires ajv-draft-04) and JSON Type Definition RFC8927. Current stable version is 8.20.0, released with monthly cadence. It is widely used, highly performant, and strictly validates data against schemas. Key differentiators include speed, strict mode, standalone code generation, and full support for the latest JSON Schema specifications. It ships with TypeScript types and provides a comprehensive API for validation, compilation, and error handling.