Conversion category
Data & spreadsheets converters
Browse private Data & spreadsheets converters that run in your browser, explain expected output, and link to focused format-pair tools.
13 tools. 13 local-first tools for Data & spreadsheets. Choose a converter by source and download format.
Data & spreadsheets
Move structured information between spreadsheet, CSV, JSON, XML, YAML, HTML and Markdown formats.
XLSXCSV
Export data from an Excel XLSX spreadsheet as a CSV for import into databases, BI tools, scripts and APIs that expect plain comma-separated values.Open converterCSVXLSX
Import a CSV data file into an Excel-compatible XLSX workbook — useful when downstream tools or colleagues require spreadsheet format with column type detection.Open converterXLSXLSX
Convert a legacy XLS spreadsheet to the modern XLSX format for compatibility with current Excel, Google Sheets and other applications that no longer support the older binary format.Open converterXLSXJSON
Export spreadsheet data as structured JSON for web applications, APIs or data pipelines. Each spreadsheet row becomes a JSON object keyed by column headers.Open converterJSONXLSX
Convert a JSON data array to an Excel spreadsheet for visual review, sharing with non-technical stakeholders or import into BI tools.Open converterJSONCSV
Flatten a JSON array to a CSV for import into databases, spreadsheets or analytics tools that require tabular plain-text input.Open converterCSVJSON
Convert a CSV file to a structured JSON array for use in web APIs, configuration files or JavaScript applications that work with JSON natively.Open converterXMLJSON
Convert XML-structured data to JSON for consumption by modern web APIs, JavaScript applications and data pipelines that work with JSON rather than XML.Open converterJSONXML
Serialize a JSON data structure as XML for integration with legacy systems, SOAP services or tools that require XML-formatted input.Open converterYAMLJSON
Convert a YAML configuration or data file to JSON for use in applications, APIs or environments that expect JSON rather than YAML.Open converterJSONYAML
Convert a JSON file to YAML for human-readable configuration, documentation or any tool that prefers YAML's indented syntax over JSON braces.Open converterHTMLMarkdown
Convert HTML content to clean Markdown for documentation, static site generators, CMS editors and version-controlled content workflows.Open converterMarkdownHTML
Render a Markdown document to HTML for direct use in a browser, web application or CMS that requires HTML input.Open converterHow to choose the right converter
- Use data converters when you need structured information in a different format for spreadsheets, APIs, imports, exports or documentation.
- Choose CSV for broad spreadsheet compatibility, JSON for web and API workflows, XML for document-like structured exchange, and YAML for readable configuration files.
- Check headers, delimiters, nested objects and number/date formatting after conversion because data formats do not represent structure in the same way.
Common Data & spreadsheets conversion use cases
- Move spreadsheet rows from XLSX into CSV or JSON for imports, dashboards and scripts.
- Convert JSON, XML and YAML when a tool expects a different structured-data format.
- Turn HTML tables into Markdown or HTML output for documentation and publishing workflows.
- Create XLSX files from JSON or CSV when teammates need to inspect data in a spreadsheet application.
Best practices for clean results
- Keep a copy of the original dataset and inspect row counts, headers and sample values after conversion.
- For nested JSON or XML, confirm how arrays and child objects are flattened before importing the result elsewhere.
- Avoid converting sensitive datasets on shared devices, even though processing is local to the browser.
Category FAQ
Data & spreadsheets conversion questions
Can CSV preserve nested JSON data?
CSV is a flat row-and-column format, so nested structures may need flattening or string values before they can be represented clearly.
Why do numbers or dates change after spreadsheet conversion?
Spreadsheet formats can apply locale, date and number interpretations. Always inspect important columns after export.
Are converted spreadsheets sent to a server?
No. ConvertME spreadsheet and data tools are designed to run locally in the browser.