OpenAPI validator. Validate OpenAPI 3.0, 3.1, and Swagger 2.0 specifications with detailed error reporting and security analysis.
100% browser-based — your data never leaves your device
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OpenAPI Validator is a free online api tool that validate openapi 3.x and swagger 2.0 specifications for correctness. It works entirely in your browser — no downloads, no installations, and no server uploads required. backend developers, QA engineers, integration specialists use OpenAPI Validator when they need a fast, privacy-respecting way to process api data without installing additional software. It supports capabilities such as spec validation, error reporting, security check. Additional features include local processing. Common use cases include validate openapi specs before publishing api documentation, find schema errors and security misconfigurations in api specifications, ensure api spec compliance with openapi 3.0 and 3.1 standards. All processing happens locally using modern browser APIs, which means your data never leaves your device. This makes OpenAPI Validator ideal for working with sensitive data, proprietary code, or any situation where privacy matters.
OpenAPI Validator is a free online api tool that helps you validate openapi 3.x and swagger 2.0 specifications for correctness. Key capabilities include spec validation, error reporting, security check. All processing is done locally in your browser — no data is uploaded, stored, or shared with any server. There are no sign-ups, no file size limits, and no hidden charges. It is commonly used to validate openapi specs before publishing api documentation.
Copy your OpenAPI 3.x or Swagger 2.0 spec (YAML or JSON) and paste it into the input area.
Press the Validate button to run the validator against your specification.
Inspect each error with its line number and description. Fix issues and re-validate until clean.
Review the security analysis section for common misconfigurations in auth schemes and API keys.
| Category | Details |
|---|---|
| Input Limits | Request timeout: Configurable (default: 30 s) |
| Response size: Browser memory bound | |
| Supported Formats | HTTP/1.1, HTTP/2, WebSocket, JSON, XML, Form data, Binary |
| Browser Engine |
|
All operations run entirely in your browser using built-in API APIs. No server uploads, no data storage, and no third-party requests.
OpenAPI Validator is ideal when you need to validate openapi specs before publishing api documentation without installing software or uploading data to a server. Since everything runs in your browser, there is no setup time and no risk of your data being stored on external servers. For for collaborative API development and testing, consider using Postman. For for lightweight REST and GraphQL debugging, Insomnia may be a better fit. OpenAPI Validator fills the gap between heavyweight desktop tools and insecure online services that require uploading your data.
No. OpenAPI Validator processes everything entirely in your browser using JavaScript. Nothing you type, paste, or upload is ever transmitted to any server. Your data never leaves your device.
OpenAPI 3.0, 3.1, and Swagger 2.0 specifications are all supported with version auto-detection.
Structural validity against the OpenAPI schema, required fields, correct data types, valid paths, proper references, and common security misconfigurations.
Validates OpenAPI 3.0, 3.1, and Swagger 2.0 specifications against the schema.
Clear error messages with line numbers and suggestions for fixes.
Analyzes security schemes and identifies common misconfigurations.
Your spec is validated locally — nothing is uploaded.
OpenAPI Validator is useful in a variety of scenarios across different workflows:
Validate OpenAPI specs before publishing API documentation
Find schema errors and security misconfigurations in API specifications
Ensure API spec compliance with OpenAPI 3.0 and 3.1 standards
The validator auto-detects OpenAPI 3.0, 3.1, or Swagger 2.0 — make sure your spec's openapi/swagger field matches the actual version used.
Run the security check early in your design process to catch common issues like missing scopes or incorrect OAuth flows.
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