jsen - JSON Schema Validator
JSON →jsen (JSON Sentinel) is a JSON Schema validator built for speed using dynamic code generation for V8 optimization. It supports JSON-Schema draft 4, remote and external schemas, custom formats and error messages, default value gathering, and greedy validation. The current stable version is 0.6.6 with low release cadence (last update 2019). It differentiates itself with performance benchmarks showing it faster than alternatives like z-schema, jsck, themis, and others. However, it lacks modern JSON Schema drafts (draft-06/07/2019-09), TypeScript types, and is not actively maintained.