Tool Overview

This tool lets you edit an OpenAPI or Swagger specification in YAML in a text area. As you type or paste, the tool checks the content after a short delay and reports structural, schema, and security issues. You can apply one-click fixes for some issues or ask for an AI explanation of an error. A preview pane shows a simple docs view (API title, version, endpoint count, schema count, and a list of paths and methods) and a validation status. Clicking an endpoint opens a detail view with summary, description, parameters, request body, responses, and security. You can copy the YAML, download it as a file, or clear the editor.

OpenAPI specs describe REST APIs in a standard format. Mistakes in YAML or in the spec structure cause broken docs or failed code generation. Checking by hand is slow and easy to miss errors. This tool validates the spec as you edit and shows what is wrong and how to fix it. It does not send real HTTP requests to your API. It only edits and validates the spec text and shows a readable summary of paths and operations.

The tool is for developers and technical writers who write or maintain OpenAPI or Swagger YAML. You need a basic idea of what OpenAPI is and how YAML is written. The validation messages and optional AI explanation help you fix issues even if you are new to the spec.

Background & Concept Explanation

OpenAPI (formerly Swagger) is a standard for describing REST APIs. The spec is usually written in YAML or JSON. It includes the API title and version, the list of paths and HTTP methods, parameters, request and response bodies, and optionally security. Many tools use this spec to generate documentation, client code, or server stubs. If the spec is invalid or incomplete, those tools fail or produce wrong output. A related operation involves referencing the ASCII chart as part of a similar workflow.

Common problems are missing or wrong YAML (indentation, colons, quotes), a missing openapi or swagger version, a missing info block or title or version, no paths or empty paths, or paths with no HTTP methods. The tool parses the YAML and checks for these and similar issues. It groups problems into structural (document shape), schema (info and fields), and security (missing security definitions). For some errors it can suggest a fix and apply it to the text so you do not have to edit by hand.

Editing a long YAML file in a plain editor gives no feedback until you run a separate validator. This tool runs validation automatically after you stop typing for a moment and shows errors in a panel with an explanation and, where possible, a fix button or an AI-generated explanation.

Key Features

• YAML editor. You edit the OpenAPI spec in a single text area. The tool starts with a sample spec so you can see the format. You can paste your own YAML or type from scratch. The content is plain text. There is a maximum length so very large files are rejected with an error. This is the main input.
• Real-time validation. The tool re-validates the spec shortly after you stop typing. It reports a list of issues with a message, category (Structural, Schema, or Security), and a short explanation. The status bar and top bar show whether the spec is valid or how many issues were found. Validation does not run on every keystroke so the page stays responsive.
• Issues panel. When there are errors or warnings, a panel lists each issue. Each item shows the category, message, and explanation. Some issues have a fix button that updates the YAML (for example adding openapi version or info block or a sample path). You click the button and the tool applies the change and shows a short confirmation. This helps you fix common mistakes quickly.
• AI explanation. For each issue you can request an AI explanation. The tool sends the error message and a portion of your YAML to a remote service and displays the returned text. This step needs network access and can fail; if it fails you see an error message. The AI does not change the spec. It only explains the issue in plain language.
• Preview: Docs tab. When the spec parses successfully the preview pane can show a docs view. It displays the API title and version, the number of endpoints (operations) and schemas, and a list of endpoints. Each endpoint shows method, path, and optional summary. Clicking an endpoint opens a detail modal with summary, description, operation ID, tags, parameters, request body, responses, and security if present. This gives you a quick read-only view of the spec without sending requests to any server.
• Preview: Status tab. The preview pane has a second tab that shows validation status. It shows Valid or the number of issues and a simple progress bar. This is a quick way to see if the spec passes validation without opening the issues panel.
• Copy, download, clear. You can copy the full YAML to the clipboard, download it as a file (openapi.yaml), or clear the editor. Copy and download use the current editor content. Clear removes all text and resets the state. These actions do not validate the spec; they only handle the text.
• Editor and preview layout. On large screens the editor and preview are shown side by side. On small screens you switch between editor and preview using a toggle or menu. The preview has two tabs (Docs and Status) so you can switch between the docs view and the validation status.

Common Use Cases

Writing a new spec. You start from the sample or an empty editor. You add openapi version, info (title and version), and paths. As you type, validation runs and tells you if something is missing or wrong. You use the fix buttons where they appear and read the explanations to fix the rest. For adjacent tasks, decoding JSON Web Tokens addresses a complementary step.

Checking an existing spec. You paste your OpenAPI YAML into the editor. The tool parses it and lists structural, schema, and security issues. You go through the list, apply fixes where available, and correct the rest by hand. When the list is empty you use the Docs tab to skim endpoints and the detail modal to check parameters and responses.

Understanding a validation error. You get an error you do not understand. You click AI Explanation for that error. The tool sends the error and context to a remote service and shows a short explanation. You use that to edit the YAML and resolve the issue.

Quick docs view. You have a valid spec and want to see its endpoints and operations. You switch to the Preview and Docs tab. You see the title, version, counts, and the list of method and path. You click an endpoint to see its summary, parameters, request body, and responses in one place. When working with related formats, checking your IP address can be a useful part of the process.

Exporting the spec. When the spec is ready you use Download to save it as openapi.yaml. You use the file in your repo, in a doc generator, or in another tool. The tool does not export to HTML or PDF; it only provides the YAML file.

How to Use This Tool (Step-by-Step)

1. Open the tool. You will see an editor with a sample OpenAPI YAML and a preview area. The top bar shows Editor and Preview and, when there are issues, a validation status.
2. Edit the YAML. Type or paste your OpenAPI spec in the left (or full-screen) editor. Use valid YAML: correct indentation, colons, and structure. The tool re-validates shortly after you stop typing.
3. Check validation. Look at the top bar or status bar for Valid or the number of issues. If there are issues, an issues panel appears. Open it and read each message, category, and explanation.
4. Fix issues. For issues that have a Fix button, click it to apply the suggested change to the YAML. For others, edit the YAML by hand using the message and explanation. You can request an AI explanation for any issue to get a short plain-language description; that step uses the network and can fail.
5. View the docs. When the spec is valid (or parseable), switch to Preview and open the Docs tab. You will see the API title, version, endpoint and schema counts, and a list of endpoints. Click an endpoint to open the detail modal with summary, description, parameters, request body, responses, and security.
6. Check status. In the Preview pane use the Status tab to see validation status (Valid or number of issues) and the progress bar.
7. Copy, download, or clear. Use the copy button to copy the full YAML to the clipboard. Use the download button to save the current YAML as openapi.yaml. Use Clear to empty the editor and start over. On small screens use the menu to switch between Editor and Preview.

Tips, Limitations & Best Practices

The tool accepts OpenAPI 2 (swagger) and OpenAPI 3 (openapi) version fields. It validates basic structure (version, info, paths, and common problems). It does not implement the full OpenAPI schema rules; some advanced or version-specific rules may not be reported.

There is a maximum YAML length. Very large specs are rejected with an error. Split the spec or reduce it if you hit the limit. In some workflows, looking up IP addresses is a relevant follow-up operation.

The editor is a plain text area. There is no syntax highlighting or auto-completion in the tool. For heavy editing you may use an external editor and paste into the tool for validation and preview.

Fix buttons apply predefined changes (for example adding openapi version, info block, or a sample path). They are safe for common cases but may not match your naming or structure. Review the result after applying a fix.

The AI explanation sends the error message and part of your YAML to a remote service. Do not paste secrets or private data into the spec if you use this feature. The AI can fail or return a generic message; the validation result does not depend on it. For related processing needs, generating color palettes handles a complementary task.

The tool does not send HTTP requests to your API. The preview and endpoint detail view only show what is in the spec. To try out requests you need a separate client or tool.

Download saves the current editor content as a single YAML file. The tool does not export to HTML or PDF. Use another tool if you need generated documentation in those formats.

On small screens only one pane (editor or preview) is visible at a time. Use the Editor and Preview buttons or the menu to switch. The issues panel remains available when there are errors.