Convert Fixed-Width Format to JSON
Free, online, no install. Upload your file and download the result in seconds.
Convert Fixed-Width Format to JSON now →Source format
Fixed-Width Format
Fixed-Width Format (FWF) is a legacy text format where each field occupies a fixed number of character positions, without delimiters. Widely used in mainframe, government, banking, and insurance data exports.
Target format
JSON
JSON (JavaScript Object Notation) is the standard data interchange format for web APIs and applications, supported by every programming language.
How it works
- 1. Click the button above to open Reparatio. Click Upload File and select your Fixed-Width Format file.
- 2. Reparatio previews your data instantly — schema, column types, and the first rows — so you can confirm the file loaded correctly.
- 3. Select JSON from the format dropdown and click Download Converted File. Done.
Common questions
Is it free?
Up to 100 rows are always free with no account required. Register a free account and verify your email to get 250 rows and 25 conversions per day. Full files require a Standard ($29/mo) or Professional ($79/mo) plan.
Is my data safe?
Files are processed in memory and never stored. They are not used for any purpose other than your conversion. See the Privacy Policy.
What's the file size limit?
Free accounts: 10 MB. Standard plan: 500 MB. Professional plan: 2 GB.
Can I automate this?
Yes — Reparatio has a REST API, CLI, Python/JS SDK, and an MCP server for AI assistants. All are available on the Professional plan ($79/mo). See the API docs.