Java JSON Schema Generator

Creating JSON Schema (Draft 6, Draft 7, Draft 2019-09 or Draft 2020-12) from your Java classes utilising Jackson.

This project consists of:

• the victools/jsonschema-generator (the only thing you need to get started)
• a few modules bundling standard configurations for your convenience:
  • victools/jsonschema-module-jackson deriving JSON Schema attributes from jackson annotations (e.g. "description", property name overrides, what properties to ignore) as well as looking up appropriate (annotated) subtypes
  • victools/jsonschema-module-jakarta-validation deriving JSON Schema attributes from jakarta.validation.constraints annotations (e.g. which properties are nullable or not, their "minimum"/"maximum", "minItems"/"maxItems", "minLength"/"maxLength")
  • victools/jsonschema-module-javax-validation deriving JSON Schema attributes from javax.validation annotations (e.g. which properties are nullable or not, their "minimum"/"maximum", "minItems"/"maxItems", "minLength"/"maxLength")
  • victools/jsonschema-module-swagger-1.5 deriving JSON Schema attributes from swagger (1.5.x) annotations (e.g. "description", property name overrides, what properties to ignore, their "minimum"/"maximum", "const"/"enum")
  • victools/jsonschema-module-swagger-2 deriving JSON Schema attributes from swagger (2.x) @Schema annotations
• the victools/jsonschema-maven-plugin allowing you to generate JSON Schemas as part of your Maven build

Another example for such a module is:

• imIfOu/jsonschema-module-addon deriving JSON Schema attributes from a custom annotation with various parameters, which is part of the module.

Documentation

JavaDoc is being used throughout the codebase, offering contextual information in your respective IDE or being available online through services like javadoc.io.

Additional documentation and configuration examples can be found here: https://victools.github.io/jsonschema-generator

Usage

Dependency (Maven)

<dependency>
    <groupId>com.github.victools</groupId>
    <artifactId>jsonschema-generator</artifactId>
    <version>4.31.1</version>
</dependency>

Since version 4.7, the release versions of the main generator library and the (standard) victools modules listed above are aligned. It is recommended to use identical versions for all of them to ensure compatibility.

It is discouraged to use an older/lower jsonschema-generator version than any of your jsonschema-module-* dependencies. If the module uses any feature only added to the jsonschema-generator in the newer version, runtime errors are to be expected.

Code

Complete/Minimal Example

import com.fasterxml.jackson.databind.JsonNode;
import com.github.victools.jsonschema.generator.OptionPreset;
import com.github.victools.jsonschema.generator.SchemaGenerator;
import com.github.victools.jsonschema.generator.SchemaGeneratorConfig;
import com.github.victools.jsonschema.generator.SchemaGeneratorConfigBuilder;
import com.github.victools.jsonschema.generator.SchemaVersion;

SchemaGeneratorConfigBuilder configBuilder = new SchemaGeneratorConfigBuilder(SchemaVersion.DRAFT_2020_12, OptionPreset.PLAIN_JSON);
SchemaGeneratorConfig config = configBuilder.build();
SchemaGenerator generator = new SchemaGenerator(config);
JsonNode jsonSchema = generator.generateSchema(YourClass.class);

System.out.println(jsonSchema.toPrettyString());

Additional examples can be found in the jsonschema-examples folder or throughout the various tests classes.