Json Schema Validator

This tool validates JSON documents against a JSON Schema using the nlohmann::json library in C++ projects. It targets developers, QA engineers, and CI workflows that require deterministic input validation, schema conformance, and reproducible error reporting. It supports core schema constructs such as type checks, required properties, nested objects, arrays, enums, const, and conditional logic, enabling precise contract enforcement during data exchanges and configuration loading.
Conceptually, users supply a schema and a data instance: the validator performs a depth-first traversal, compares each node against its corresponding schema rule, and records any mismatch with a path and a human-friendly message. Implementation relies on recursive descent, strict type matching, and an error collector that aggregates all violations in a single run, preserving the original data structure for traceability.
The tool exposes options for strict mode, reference resolution, draft compatibility, and optional behaviors such as allowing additionalProperties or treating unknown keywords with warnings. It returns a boolean valid result and a detailed errors list when invalid. Its design favors deterministic outcomes, predictable error ordering, and stable performance on large documents by streaming checks and memoizing resolved definitions where possible.
Unique value comes from tight integration with a widely adopted C++ JSON library, comprehensive schema support aligned with common practice, and structured error reporting suitable for automated tooling. Core features include in-memory validation, JSON Pointer-based error locations, and clear interfaces for embedding in unit tests or CI pipelines. Use cases span API response validation, configuration file verification, data fixture testing, and cross-system data validation in microservices.