Getting Started

Install ESLint and the plugin:

npm install --save-dev eslint eslint-plugin-json-schema-validator-2

Enable the recommended Flat Config preset:

import jsonSchemaValidator from "eslint-plugin-json-schema-validator-2";

export default [...jsonSchemaValidator.configs.recommended];

The recommended preset registers parsers for JSON, JSONC, JSON5, YAML, and TOML files and enables json-schema-validator-2/no-invalid as a warning for those files.

The complete option reference is in the no-invalid rule docs. The broader README is available in the repository root.

Custom schemas

Pass schemas directly to the rule when a file does not advertise a $schema property or when you need to override SchemaStore detection:

export default [
 ...jsonSchemaValidator.configs.base,
 {
  rules: {
   "json-schema-validator-2/no-invalid": [
    "error",
    {
     schemas: [
      {
       fileMatch: ["config/*.json"],
       schema: "./schemas/config.schema.json",
      },
     ],
     useSchemastoreCatalog: false,
    },
   ],
  },
 },
];

YAML schema comments

YAML files can use a language-server directive when the validated data cannot include a $schema property:

# yaml-language-server: $schema=./schemas/config.schema.json
enabled: true

The rule prefers a normal YAML $schema property when one exists, then falls back to the directive comment.

Reporting and cache settings

Use reportMode: "most-specific" to hide broad parent errors when deeper errors already identify the failing value:

export default [
 ...jsonSchemaValidator.configs.base,
 {
  rules: {
   "json-schema-validator-2/no-invalid": [
    "error",
    {
     reportMode: "most-specific",
    },
   ],
  },
 },
];

Remote schemas are cached automatically for 30 days. The default cache uses node_modules/.cache/eslint-plugin-json-schema-validator-2 when the plugin is installed under node_modules, and falls back to .cache/eslint-plugin-json-schema-validator-2 in the ESLint current working directory. Configure the cache from shared settings when CI or local tooling needs a specific location:

export default [
 {
  settings: {
   "json-schema-validator-2": {
    cache: {
     directory: ".cache/json-schema-validator-2",
     ttl: 1000 * 60 * 60 * 24 * 30,
    },
   },
  },
 },
];

Set ttl: false if you want to keep using cached remote schemas without scheduling background refreshes.

Markdown frontmatter

Use configs.frontmatter to validate leading YAML frontmatter in Markdown, MDX, or MDC files. The processor exposes the frontmatter as a virtual *.frontmatter.yaml file:

export default [
 ...jsonSchemaValidator.configs.frontmatter,
 {
  rules: {
   "json-schema-validator-2/no-invalid": [
    "error",
    {
     schemas: [
      {
       fileMatch: ["**/*.frontmatter.yaml"],
       schema: "./schemas/frontmatter.schema.json",
      },
     ],
     useSchemastoreCatalog: false,
    },
   ],
  },
 },
];