lookup> .nns

.NNS·File Extension

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

Data & Textapplication/vnd.noblenet-sealer

Quick facts

Extension.nns

File typeNNS Data & Text

MIME typeapplication/vnd.noblenet-sealer

CategoryData & Text

Charset—

Compressible—

What is .nns

What is a .nns file?

A .nns file is a NNS 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/vnd.noblenet-sealer. When serving .nns over HTTP, set the Content-Type header as shown in Developer info below.

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

How to open .nns files

Use VS Code or Notepad++ to open and edit .nns 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/vnd.noblenet-sealer

Common software that reads/writes .nns:

VS CodeNotepad++Sublime Textjq

Relation chain

.nnsextension of

format

NNS Data & Textserved as

mime type

application/vnd.noblenet-sealersent via header

http header

Related extensions

Related MIME types

application/vnd.noblenet-sealer

.nns

Common uses

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

How to edit .nns 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 .nns files

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

Frequently asked questions

What programs can open .nns 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 .nns file?

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

What is the relationship between .nns and the application/vnd.noblenet-sealer MIME type?

application/vnd.noblenet-sealer is the media type identifier used for .nns files during network transfer (for example in the HTTP Content-Type header).

Sources & standards

Updated 2026-09-13

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