Fibonacci ToolBox

CSV ⇄ Excel

Turn CSV files into an .xlsx workbook (one sheet each), or every sheet of a workbook into CSVs.

CSV ⇄ Excel options
Files
Drop files here or click to browse
CSV, TSV, XLSX · up to 25 MB each, 10 max · paste works too
Runs in the background · stops after 120s
Results appear hereAdd your files, adjust the options and press Run.
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JSON formatter

Validate, pretty-print or minify JSON, with exact error positions.

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JSON ⇄ YAML ⇄ TOML

Convert configuration between JSON, YAML and TOML.

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CSV ⇄ JSON

Convert CSV to an array of JSON objects, or JSON records back to CSV (nested keys flattened).

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JSON to types

Generate TypeScript interfaces, Pydantic models, Zod schemas or Go structs from a JSON sample.

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