OpenAPI Validator is a configurable validator and linter for OpenAPI documents.
Developed by IBM, it checks OpenAPI 3.0.x and 3.1.x definitions for compliance with the specification as well as IBM-defined best practices. The tool is designed for command-line use and supports project-specific customization through rulesets and configuration files, making it suitable for validating API descriptions in local development workflows, CI pipelines, and automated quality checks.
This is free and open source software.
Key Features
- Validates OpenAPI 3.0.x and 3.1.x documents.
- Checks API definitions against the OpenAPI specification and IBM-defined best practices.
- Supports custom rulesets and can use standard Spectral ruleset files.
- Offers configurable behaviour through JSON, YAML, or JavaScript configuration files.
- Produces human-readable text output or JSON output for automation and scripting.
- Available as an npm package, platform-specific binary, or container image.
- Cross-platform support – runs under Linux, macOS, and Windows.
Website: github.com/IBM/openapi-validator
Support:
Developer: IBM
License: Apache License 2.0

OpenAPI Validator is written in JavaScript. Learn JavaScript with our recommended free books and free tutorials.
Related Software
| OpenAPI Linters | |
|---|---|
| Spectral | Fexible JSON/YAML linter |
| vacuum | OpenAPI and Swagger linter |
| Redocly | All-in-one OpenAPI utility |
| Cherrybomb | Audit, validate, run API tests |
| Zally | Minimalistic, simple-to-use API linter |
| speccy | Enforce quality rules on your OpenAPI specifications |
| Rate My OpenAPI | Improve the quality of your OpenAPI specifications |
| OpenAPI Validator | Configurable and extensible validator/linter |
| OpenAPI Spec validator | Validates OpenAPI Specs |
| oval | CLI for (O)penAPI Specification document (val)idation |
| OpenAPI Linter | CLI and a Node.js library |
| OAS-Kit | Convert Swagger 2.0 definitions to OpenAPI 3.0 |
Read our verdict in the software roundup.
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