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.LESS·File Extension

LESS Data & Text — A .less file is a LESS Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

Data & Texttext/lessCompressible

Quick facts

Extension.less

File typeLESS Data & Text

MIME typetext/less

CategoryData & Text

Charset—

CompressibleYes

What is .less

What is a .less file?

A .less file is a LESS Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

In the mime-db registry it maps to text/less, and it is marked as compressible. When serving .less over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to text/less and is used by Less among others — and is delivered over HTTP via the Content-Type header.

How to open .less files

Use VS Code or Notepad++ to open and edit .less files.
Any text editor (Notepad, VS Code) can inspect the raw content as text.

Developer info

When served over HTTP, responses should set the following header:

Content-Type: text/less

Common software that reads/writes .less:

VS CodeNotepad++Sublime Textjq

Relation chain

.lessextension of

format

LESS Data & Textserved as

mime type

text/lesssent via header

http header

Related extensions

Related MIME types

Related programming languages

Less

.less

Common uses

Configuration files
Data interchange between systems
API request and response payloads
Logs and data exports

How to edit .less files

Open the file with VS Code, make your changes and save.
Most editors preserve the original formatting and encoding — avoid changing the charset.

How to create .less files

Create a new file and save it with the .less extension, or export this format from VS Code.

Frequently asked questions

What programs can open .less files?

Common options include VS Code, Notepad++, Sublime Text. You can also open many of these files with built-in viewers or a browser.

How do I create a .less file?

Create a new file in any text editor or the app that owns the format and save it with the .less extension.

What is the relationship between .less and the text/less MIME type?

text/less is the media type identifier used for .less files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-09-13

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