lookup> .tcl

.TCL·File Extension

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

Data & Textapplication/x-tcl

Quick facts

Extension.tcl

File typeTCL Data & Text

MIME typeapplication/x-tcl

CategoryData & Text

Charset—

Compressible—

What is .tcl

What is a .tcl file?

A .tcl file is a TCL 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 application/x-tcl. When serving .tcl over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to application/x-tcl and is used by Tcl among others — and is delivered over HTTP via the Content-Type header.

How to open .tcl files

Use VS Code or Notepad++ to open and edit .tcl 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: application/x-tcl

Common software that reads/writes .tcl:

VS CodeNotepad++Sublime Textjq

Relation chain

.tclextension of

format

TCL Data & Textserved as

mime type

application/x-tclsent via header

http header

Related extensions

Related MIME types

Related programming languages

Tcl

.tcl .adp .sdc

Common uses

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

How to edit .tcl 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 .tcl files

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

Frequently asked questions

What programs can open .tcl 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 .tcl file?

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

What is the relationship between .tcl and the application/x-tcl MIME type?

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

Sources & standards

Updated 2026-08-18

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