node-blaze
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Bindings to blaze, high-performance C++ JSON Schema validator
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Blaze
=====
The ultra high-performance JSON Schema validator for C++ with support for JSON
Schema Draft 4, Draft 6, Draft 7, 2019-09, and 2020-12.
[](https://doi.org/10.5281/zenodo.14867298)
Want to use Blaze without writing C++? Check out our [JSON Schema
CLI](https://github.com/sourcemeta/jsonschema), which is powered by Blaze, and
offers advanced functionality like [`validate
--trace`](https://github.com/sourcemeta/jsonschema/blob/main/docs/validate.markdown)
for debugging schema evaluation.
Benchmark
---------
The 2025 paper [Blaze: Compiling JSON Schema for 10x Faster
Validation](https://arxiv.org/abs/2503.02770) presents a reproducible benchmark
comparing Blaze against a number of popular JSON Schema validators, concluding
that Blaze is on average _at least_ 10x faster than competitors given a large
set of representative schemas and instances.
[](https://arxiv.org/abs/2503.02770)
Features
--------
- **Performance:** Blaze compiles JSON Schema into a lower-level intermediate
language for ultra fast evaluation. It can achieve schema validation in the
nano-second range, making it a perfect fit for low-latency gateways and
validation of large datasets
- **Compliance:** Blaze achieves a 100% compliance score in the official
[Bowtie](https://bowtie.report/#/implementations/cpp-blaze) benchmark, while
popular validators like [AJV](https://bowtie.report/#/implementations/js-ajv)
only achieve an average 85% compliance. It also supports the [Standard
Output](https://json-schema.org/draft/2020-12/json-schema-core#name-output-formatting)
format (Flag, and Basic). Furthermore, Blaze is built and maintained by a
[JSON Schema TSC member](https://www.jviotti.com)
- **Extensibility:** Blaze supports the implementation of custom vocabularies
of arbitrary complexity, and the ability to setup custom resolution of
external schemas from arbitrary sources, like from HTTP, filesystem,
databases, etc
- **Annotations:** Blaze is one of the few implementations that fully supports
annotation extraction during evaluation to augment instances with semantic
information, making it a great fit for data science scenarios Blaze also
adheres to the [annotations official test
suite](https://github.com/json-schema-org/JSON-Schema-Test-Suite/tree/main/annotations)
Example
-------
Blaze is designed to be easy to use, while at the same time providing extensive
hooks for supporting custom vocabularies, resolving external schemas, and more.
```cpp
// (1) Get a JSON Schema
const auto schema{sourcemeta::core::parse(R"JSON({
"$schema": "https://json-schema.org/draft/2020-12/schema",
"type": "string"
})JSON")};
// (2) Compile the JSON Schema into an optimised representation
const auto compiled_schema{sourcemeta::blaze::compile(
schema,
// These options allow you tweak how Blaze works,
// the JSON Schema vocabularies it understands,
// and how to resolve references to external schemas
sourcemeta::core::schema_official_walker,
sourcemeta::core::schema_official_resolver,
sourcemeta::blaze::default_schema_compiler,
// Fast validation means getting to a boolean result
// as fast as possible. Check out the documentation
// for how to get detailed error information and/or
// collect JSON Schema annotations
sourcemeta::blaze::Mode::FastValidation)};
// (3) Get a JSON instance
const sourcemeta::core::JSON instance{"Hello Blaze!"};
// (4) Validate the instance against the schema
sourcemeta::blaze::Evaluator evaluator;
const auto result{evaluator.validate(compiled_schema, instance)};
if (result) {
std::cout << "Success!\n";
}
```
Documentation
-------------
Refer to the project website for documentation:
[https://blaze.sourcemeta.com](https://blaze.sourcemeta.com).
Roadmap
-------
- Support running the validator on [simdjson](https://github.com/simdjson/simdjson)
- Provide bindings to higher-level programming languages (Node.js, Go, etc)
Contributors
------------
Blaze was designed and developed by a team of passionate JSON Schema developers
and researchers.
<a href="https://github.com/sourcemeta/blaze/graphs/contributors">
<img src="https://contrib.rocks/image?repo=sourcemeta/blaze" />
</a>