HTML Preview Tool for API Responses

About This Tool

Working with REST APIs, GraphQL endpoints, and webhooks means constantly processing HTML response data. Raw API responses are typically minified — stripped of all whitespace and line breaks to minimize payload size — making them virtually impossible to read without formatting. This tool transforms those compact responses into well-structured, readable output that reveals the data hierarchy and makes it easy to locate specific values. Paste a response from Postman, cURL, browser DevTools Network tab, or any API client, and instantly see the formatted result. The tool validates the response structure during processing, catching malformed responses that might cause subtle bugs in your application. For developers debugging production issues, this immediate visibility into API data structures is invaluable.

What is HTML Preview Tool?

An HTML preview tool renders HTML code in a sandboxed iframe, giving you a live visual preview of how your markup will look in a browser. The preview is sandboxed for security — scripts are restricted to prevent malicious code execution. This is useful for quickly testing HTML snippets, email templates, CSS styling, and layout experiments without creating a full HTML file or setting up a development server. The preview updates as you type, providing immediate visual feedback. It is particularly valuable for email template development, where different HTML rendering engines require careful testing of markup and inline styles.

How to Use This Tool

1. Type or paste HTML in the input area.
2. See the live preview below.
3. Edit and see changes immediately.
4. The preview is sandboxed for security.

Common Use Cases

• Formatting raw API response bodies for debugging
• Processing webhook payloads for analysis
• Cleaning up GraphQL query responses
• Inspecting third-party API data structures

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