OpenAPI validation tool

A good OpenAPI validation tool depends on what you want to validate:

Popular options

• Redocly CLI – great all-around OpenAPI linting and validation
• Swagger CLI / Swagger Editor – widely used, easy for OpenAPI 3.x
• OpenAPI Generator validate – useful if you already use OpenAPI Generator
• Spectral – very popular for linting rules and style checks
• IBM OpenAPI Validator – good for stricter validation
• openapi-spec-validator (Python) – simple validation library
• oas-validator / @apidevtools/swagger-parser (Node.js) – good for parsing and validation

If you want a quick recommendation

• For CI/CD and linting: Spectral
• For strict spec validation: Redocly CLI or Swagger CLI
• For Python projects: openapi-spec-validator
• For Node.js projects: swagger-parser

Example commands

Spectral

npm install -g @stoplight/spectral-cli
spectral lint openapi.yaml

Swagger CLI

npm install -g swagger-cli
swagger-cli validate openapi.yaml

Redocly

npm install -g @redocly/cli
redocly lint openapi.yaml

If you want, I can also give you:

1. a comparison table,
2. a recommendation for your language/tooling, or
3. a GitHub Actions CI example.