.json — JavaScript Object Notation
Data application/json
What a .json file is
The dominant data interchange format on the web: nested objects and arrays of strings, numbers, booleans and null.
How to open it
Any text editor. Format and validate it here.
Worth knowing
JSON has no comments and no trailing commas. Both are the most common syntax errors.
How to identify a .json file
A file's extension is only its name — renaming a.png to a.json changes nothing inside. What software actually reads is the magic number, the first few bytes of the file.
| Signature | none |
| MIME type | application/json |
| Category | Data |
Plain text. Usually starts with { or [ but that is convention, not a signature.
# what is this file really?
file mystery.json
# look at the first bytes yourself
xxd mystery.json | head -2
head -c 16 mystery.json | xxd
# Windows PowerShell
Get-Content mystery.json -AsByteStream -TotalCount 16 | Format-HexFrequently asked questions
What is a .json file?
The dominant data interchange format on the web: nested objects and arrays of strings, numbers, booleans and null.
How do I open a .json file?
Any text editor. Format and validate it here.
Is .json safe to open?
Yes. A .json file is data, not code — opening one cannot execute anything by itself.
Can I change a file's extension to convert it?
No. Renaming changes the label, not the bytes. The one place it appears to work is between formats that genuinely share a container — renaming .docx to .zip works because a DOCX is a ZIP. Everything else needs a real converter.
Other data formats
- .csv — Comma-Separated Values
- .yaml — YAML Ain't Markup Language
- .sql — SQL Script
- .parquet — Apache Parquet