Document Converter

Transform documents instantly. Secure, client-side, and free.

InputMarkdown
OutputHTML

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Document Converter: JSON, CSV, Markdown & PDF Tools

Data comes in many shapes and sizes. Developers love JSON, Data Scientists love CSV, Writers love Markdown, and Business Managers love PDF. The problem arises when these worlds collide.

Welcome to the Universal Document Converter, a secure, client-side toolkit designed to bridge the gap between file formats instantly.

Why Use This Converter?

Most online file converters are black boxes. You upload a file, wait, and hope your data isn't being stored on a server somewhere. Our tool is different:

  • 100% Client-Side: Your data never leaves your browser. Whether you are converting sensitive financial CSVs or proprietary JSON code, the processing happens locally on your device.
  • Instant Preview: Don't download a file just to see if it worked. Switch between "Code View" and "Preview Mode" to inspect the results instantly.
  • Developer Friendly: We preserve syntax, handle nesting correctly, and offer cleaner output than standard converters.

Supported Conversions

Markdown ↔ HTML

Markdown → HTML: Perfect for bloggers. Write in simple text and convert it to web-ready code for your CMS (WordPress, Ghost, etc.).

HTML → Markdown: Great for migrating content. Move old blog posts into a modern static site generator (Hugo, Jekyll) by stripping tags into clean text.

JSON ↔ CSV

JSON → CSV: The analyst's favorite. Convert nested API responses into flat spreadsheets for Excel or Google Sheets.

CSV → JSON: Developers often receive data in spreadsheets. This tool converts rows into structured JSON arrays for database seeders.

YAML ↔ JSON

YAML: Used heavily in DevOps (Kubernetes, Docker) for readability.

JSON: Used by APIs. If you need to debug a Kubernetes manifest using a JSON tool, we handle the indentation logic perfectly.

Text → PDF

Need to turn a quick note, code snippet, or readme into a shareable document? Our PDF generator creates a clean, printable PDF file directly from your browser.

JSON ↔ XML

JSON → XML: Often needed for integrating with legacy enterprise systems, SOAP APIs, or generating RSS feeds.

XML → JSON: Modernize your data. Convert verbose XML configurations or soap responses into lightweight JSON for use in modern web applications.

Technical Guide: Data Structures

1. JSON (JavaScript Object Notation)

The language of the web. It supports nested objects and arrays. Pros: Highly flexible. Cons: Hard for humans to read in large chunks.

2. CSV (Comma Separated Values)

The language of spreadsheets. Pros: Great for tables and math. Cons: Cannot handle nested data well (nested objects are often stringified).

3. YAML (YAML Ain't Markup Language)

The language of configuration. Pros: Minimal syntax (indentation-based). Cons: Very strict about whitespace.

4. XML (eXtensible Markup Language)

The classic standard for enterprise data. It looks like HTML but is designed to store data, not display it. Pros: Extremely structured and validation-friendly. Cons: Verbose and heavier than JSON.

Pro Tips for Conversion

  • Validate Your JSON: Before converting, ensure your JSON is valid. A missing comma will fail the conversion.
  • Check CSV Headers: When converting CSV to JSON, ensure your first row contains column headers. These become the "Keys".
  • Markdown Images: When converting Markdown to HTML, ensure text paths like `![alt](url)` are publicly accessible if you plan to host the HTML.

Frequently Asked Questions

Is my data safe/secure? (Privacy Policy)
Yes, absolutely. This tool operates 100% Client-Side. This means your data (whether it's confidential financial CSVs or private notes) never leaves your browser. It is not uploaded to our servers, not stored in any database, and not seen by anyone but you.
How do I convert JSON to CSV for Excel?
Simply paste your JSON array into the input box and select "JSON to CSV". The tool will automagically extract the keys (headers) from the first object and format the data as Comma Separated Values. You can then download the .csv file and open it directly in Excel, Numbers, or Google Sheets.
Can I convert nested JSON objects to CSV?
Yes, but with limitations. CSV is a "flat" 2D format, while JSON can be highly dimensional (nested). Our tool will "stringify" nested objects into a single cell so you don't lose data, but for the best results, we recommend flattening your JSON into a simple array of objects before conversion.
Why use YAML instead of JSON?
Readability. JSON is full of brackets {} and quotes "" which make it hard for humans to scan. YAML uses indentation and practically no punctuation, making it the preferred standard for Configuration files (Docker, Kubernetes, Home Assistant).
Can I convert Excel (.xlsx) files?
Directly? No (because .xlsx is a binary zip format). However, you can simply open your Excel file, go to File > Save As > CSV, and then upload that CSV file here to convert it to JSON or YAML.
Does this support GitHub Flavored Markdown?
Yes! We use the advanced marked engine which supports GFM tables, task lists - [ ], strikethrough ~~text~~, and auto-linked URLs.
How can I reduce JSON file size?
Use our "Minify" feature (the standard "Minimize" icon in the toolbar). This strips all unnecessary whitespace, newlines, and indentation from your JSON, often reducing file size by 20-30% for production use.
Can I convert HTML emails to text?
Absolutely. The "HTML to Markdown" converter is excellent for cleaning up messy HTML emails. It strips away the layout tables and excessive styling, leaving you with just the readable content and links.
Does this work offline?
Yes. Once you load this page, you can disconnect your internet and still use every feature. This is because the conversion logic is downloaded to your browser and runs locally in JavaScript.
How to fix "Invalid JSON" errors?
JSON is strict. Common errors include:
  • Using single quotes ' instead of double quotes " for keys.
  • Leaving a trailing comma at the end of a list [1, 2,].
  • Unescaped special characters inside strings.
Our tool will usually point out the syntax error location.
Can I convert PDF back to Text?
Not currently. PDF is a "visual" format, not a "data" format, making it very difficult to extract clean structured text from it accurately in the browser. We focus on creating PDFs from text.
Is there a file size limit?
Only what your browser can handle. Generally, files up to 10MB-20MB convert instantly. Files larger than 50MB may cause your browser tab to freeze momentarily while processing, but it will usually succeed.