# networknt/json-schema-validator

A fast Java JSON schema validator that supports draft V4, V6, V7, V2019-09 and V2020-12

Repository: https://github.com/networknt/json-schema-validator
Canonical: https://ross.abutalabs.com/products/networknt-json-schema-validator
Language: Java
License: Apache-2.0
License Family: permissive
Topics: json-schema-validator, json-schema, fast, java8, draft, v4, jackson, java, v6, v7, v2019-09, draftv4, draftv6, draftv7, json, yaml, openapi3, v2020-12
Last push: 2026-08-26T02:07:17+00:00

## Health v2 (maintenance only)
Score: 95/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 86, longevity 100
- inputs: {"age_days": 3639, "days_push": 8, "days_rel": 13, "gap_med": 35.0, "n_releases_24m": 23}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1078, forks 353 (observed 2026-08-28T04:03:29.884212+00:00)

## What it is
A fast Java library for validating JSON and YAML documents against JSON Schema drafts v4, v6, v7, 2019-09, and 2020-12, built on the Jackson parser. It supports custom dialects, vocabularies, keywords, and OpenAPI 3 request/response validation, and powers request validation in the light-4j microservices framework.

## Use cases
- validate json payloads against a json schema in java
- validate openapi 3 request and response bodies at runtime
- check yaml config files against a schema
- support multiple json schema draft versions in one app
- high-performance schema validation for microservices
- customize json schema dialects and keywords

## When to choose
- you need a fast, actively maintained JSON Schema validator on the JVM
- you must support multiple schema drafts including 2020-12
- you validate OpenAPI 3 requests/responses in a Java service
- you need custom dialects or vocabularies

## When to avoid
- your project is not on the JVM
- you need a CLI or standalone validator rather than an embeddable library
- you need non-JSON formats like XML schema validation

## Facets
- artifact type: library
- maturity: active
- function: serialization, parser, testing
- domain: developer-tools, apis, backend, web-development
- platform: jvm, cross-platform
- tags: json-schema, jackson, openapi3, yaml, validation, draft-v4, draft-v7, draft-2020-12

## Member repositories
- networknt/json-schema-validator (main) score 95

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:29.884212+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:53:10.916942+00:00, confidence not recorded.
  - readme: https://github.com/networknt/json-schema-validator (fetched 2026-08-28T04:03:29.884212+00:00, sha a516ba5f695b)
- Data as of 2026-08-30T08:39:29.467469+00:00.