Withdata DataFileConverter converts JSON files to Fixed-Width Text locally — single file, batch, or merge multiple JSON files into one Fixed-Width Text. Object arrays, plain arrays and JSON Lines are all supported. 100% local, secure, and cross-platform.

JSON is a widely used structured data format.

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Why Choose Withdata JSON to Fixed-Width Text Converter?

🔒 100% Local & Secure

JSON files are read and converted on your own computer. Nothing is uploaded to any cloud server.

⚡ Fast Streaming Conversion

Large JSON files are processed in streaming mode with low memory usage — millions of rows within a minute.

📁 Batch & Merge

Batch convert many JSON files to Fixed-Width Text files, or merge multiple JSON files into one Fixed-Width Text.

🔄 Column Widths, No Delimiter

Define the width of every column (N columns need N-1 widths). No delimiter and no quoting are needed.

🖥 Windows, macOS, Linux

Native builds for Windows, macOS and Linux, with a step-by-step GUI wizard and a command line interface.

⏱ CLI & Scheduled Tasks

Save a conversion session and run it automatically from Windows Task Scheduler or crontab.

Full Feature Comparison

Feature	Supported details
Input source	Local JSON, batch JSON, merged JSON, URL / cloud JSON
Output format	Fixed-width text with detected or custom column widths
Conversion mode	Single file · merge many JSON files into one Fixed-Width Text · batch (one to one)
Running mode	GUI wizard · command line · scheduled tasks
Source options	Object array / JSON Lines mode, nested flattening, encoding
Output options	Column mapping, encoding, date format, empty value handling
Platform	Windows, macOS, Linux (native, 64-bit)

All JSON to Fixed-Width Text Conversions You Need

Single JSON file → Fixed-Width Text file, step by step in the GUI wizard
Batch convert multiple JSON files → multiple Fixed-Width Text files
Merge multiple JSON files into one Fixed-Width Text — merge tool
Convert JSON to Fixed-Width Text in the command line, and run it as a scheduled task
All JSON conversion tools and all Fixed-Width Text conversion tools

JSON to Fixed-Width Text Notes

A JSON object array, a plain array or JSON Lines (one object per line) can be read.
Nested objects and arrays are flattened into columns.
Deep nesting levels and UTF-8 files with BOM are handled.
Output column widths are detected from the data (measured width + 15% slack, at least 2 and at most 15 extra characters), or set manually.

How to Convert JSON to Fixed-Width Text (4 Steps)

Open Withdata DataFileConverter and select JSON as the input type and Fixed-Width Text as the output type.
Load your JSON data — a single file, a folder / list of files for batch conversion, or several files to merge into one.
Check the preview table, then adjust the source options and the output options.
Click Convert — the Fixed-Width Text output is written in seconds. Save the session if you want to run it again from the command line.

Convert JSON to Fixed-Width Text in GUI

In GUI mode the conversion is a step-by-step wizard: choose the JSON source, choose the Fixed-Width Text destination, check the preview, and click Convert. See Withdata DataFileConverter.