Free File Converter Tools – CSV to JSON, HTML to Markdown & JSON to Excel
Data format mismatches between spreadsheets, APIs, and documentation tools are a constant friction point in technical workflows. CSV-to-JSON converts flat table data for API testing and JavaScript use. HTML-to-Markdown strips formatting for content migration and documentation workflows. JSON-to-Excel exports structured API data for stakeholder reporting in a format non-technical teams can work with.
CSV to JSON Converter
Convert CSV files to JSON format online free - no login. Paste or upload a CSV and instantly get a clean, formatted JSON array. Supports headers, custom delimiters, and download.
HTML to Markdown Converter
Convert HTML code to Markdown format online free - no login. Paste raw HTML and get clean, readable Markdown output instantly. Supports headings, links, lists, bold, and images.
JSON to Excel Converter
Convert JSON data to Excel spreadsheet online free - no login. Paste a JSON array and download a formatted .xlsx file instantly, with automatic column headers from object keys.
How to use these tools
Select the tool that matches your task, open it, and follow the steps below.
- Pick the converter that matches your data: CSV to JSON, HTML to Markdown, or JSON to an Excel workbook.
- Paste your data (a CSV can also be loaded from a file) - conversion runs in your browser and nothing is uploaded to a server.
- Copy the result, or download it as a .json file or an .xlsx workbook where the converter offers a download.
Common ways to use these tools
- Turn a spreadsheet export into a JSON array of objects for an API test or a script, with the first row used as keys.
- Move an HTML snippet into a README, wiki or Markdown-based CMS without retyping headings, lists, links and tables.
- Give non-technical colleagues API data as an Excel workbook, with nested fields flattened into columns such as address.city.