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NSF files which end in the .NSF extension are most commonly IBM Lotus Notes database files.

A Lotus Notes database .NSF file stores Lotus Notes information. That information consists of user data, metadata and also design information. There are many different types of Lotus Notes databases, the most common being mailbox databases used to store Lotus Notes mail, usually on a Domino server, or address book databases which are usually stored on a users PC and contain multiple contact records.

This site provides an introduction to the IBM Lotus Notes NSF file. Hopefully you will find the information here useful. If you have any comments or would like to post some information that you think may assist others please go to our submit information page and post us a message.


What applications read .NSF files?

The following applications will read .NSF files:

  • IBM Lotus Notes Client (client software installs to a PC)
  • IBM Domino Server (server software also referred to as Lotus Notes server)
  • 3rd Party Lotus Notes Applications - which require at least the Lotus Notes Client installed before use


What is the .NSF file format?

The Lotus Notes .NSF file format is proprietary to IBM. It is complex and is constantly changing with different releases of Lotus Notes. The format is known as ODS which stands for On Disk Structure. There are many versions of ODS that relate to different versions of Lotus Notes. You access and read an .NSF file using the Lotus Notes Client, Lotus Notes Server, a 3rd party application (Lotus Notes client must be installed) or if you are a developer through the Lotus Notes API (for which the Lotus Notes client must also be installed).

...more on the NSF File Format and ODS

Is there a Lotus Notes Reader or Lotus Notes Viewers for .NSF files?

No, there are no known standalone 3rd party .NSF file readers or viewers. People often say they do not want to download Lotus Notes they just want small reader program to reader the file. I am sorry but there are none we have seen in the past 15 years however the Lotus Notes Client will read these files. Trial or beta versions of Lotus Notes are available to download from IBM (see download section below). As the .NSF format is proprietary, complex and constantly changing we believe the likelihood that a standalone viewer or reader will become available is extremely low.


Download reader / viewer


Associated file extensions

The following files extensions are also used for Lotus Notes / Domino files.

  • NS4 - Lotus Notes Version 4 databases (limited to)
  • NS5- Lotus Notes Version 5 databases (limited to)
  • NS6- Lotus Notes Version 6 databases (limited to)
  • NS7- Lotus Notes Version 7 databases (limited to)
  • NTF - Lotus Notes Database Template


Most common .NSF files

There are many types of .NSF Files which are Lotus Notes databases. The most common are listed below:

  • Mailbox
  • Address Book (often called names.nsf)
  • ...there are many more

Lotus Notes databases can be custom designed so can be of any type.


Converting .NSF files

You can convert .NSF files to other formats but usually to do that you will need a 3rd party tool. Some common formats you may need to convert to are listed below:

There are various tools available to covert NSF files to other formats. See converting NSF to PST files for more information about converting NSF files to Microsoft Outlook.