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.ONETOC2·File Extension

ONETOC2 Data & Text — A .onetoc2 file is a ONETOC2 Data & Text. It is a text-based data format widely used for configuration files, data interchange and API payloads.

Data & Textapplication/onenote

Quick facts

Extension.onetoc2

File typeONETOC2 Data & Text

MIME typeapplication/onenote

CategoryData & Text

Charset—

Compressible—

What is .onetoc2

What is a .onetoc2 file?

A .onetoc2 file is a ONETOC2 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/onenote. When serving .onetoc2 over HTTP, set the Content-Type header as shown in Developer info below.

Related entities: it maps to application/onenote — and is delivered over HTTP via the Content-Type header.

How to open .onetoc2 files

Use VS Code or Notepad++ to open and edit .onetoc2 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/onenote

Common software that reads/writes .onetoc2:

VS CodeNotepad++Sublime Textjq

Relation chain

.onetoc2extension of

format

ONETOC2 Data & Textserved as

mime type

application/onenotesent via header

http header

Related extensions

Related MIME types

.onetoc .onetoc2 .onetmp

Common uses

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

How to edit .onetoc2 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 .onetoc2 files

Create a new file and save it with the .onetoc2 extension, or export this format from VS Code.

Frequently asked questions

What programs can open .onetoc2 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 .onetoc2 file?

Create a new file in any text editor or the app that owns the format and save it with the .onetoc2 extension.

What is the relationship between .onetoc2 and the application/onenote MIME type?

application/onenote is the media type identifier used for .onetoc2 files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-09-13

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