NSSM

Free plan Windows

What NSSM is

NSSM runs an application as a Windows service, monitors it, and can restart it after it exits. A graphical interface handles service installation and removal, while command-line options allow service configuration from scripts. On exit, NSSM can restart the application, ignore the exit, exit itself, or exit uncleanly to trigger Windows service recovery actions. It records its own progress in the Windows system Event Log and can redirect the monitored program's input and output. Output files can be rotated at a configurable size, including while the application is running. Other controls include setting process priority and CPU affinity, and starting, stopping, or querying services. NSSM is public domain, and its source code may be used for any purpose. The site lists 32-bit and 64-bit binaries and says it should work on Windows 2000 or later. The latest listed release is version 2.24, dated 2014-08-31; a 2.24 prerelease build is dated 2017-04-26. Managing services requires administrator access, and the site warns that bugs can cause severe system issues.

Who it suits

NSSM suits Windows users who need to run and monitor applications as services, with optional restart behavior and logging. Its scriptable configuration may also help administrators automating service setup.

What it does well

Graphical service installation and removal
Command-line options support scripted configuration
Can redirect application input and output
Public domain, with source code usable for any purpose

What to know first

Managing services requires administrator access
Latest listed release is version 2.24 from 2014
The site warns bugs can cause severe system issues

Limits

The free plan is listed as free. Managing services requires administrator access, and the site lists bugs affecting several cases, including newer Windows service startup and log rotation over 4 GB.

Plans

Plan	Billed and limits	Price
NSSM	Public domain; Windows service helper; 32-bit and 64-bit binaries	Free

As nssm.cc lists them, read 4 Oct 2026. The maker's own page has the final word.

Getting started

Open the NSSM website.
Choose the 32-bit or 64-bit binary for Windows.
Run NSSM with administrator access to manage services.
Install or remove a service through the graphical interface, or configure it with command-line options.

Verdict

NSSM provides service setup, monitoring, restart choices, and output handling for Windows applications. Readers should weigh its old latest listed release and the site's warning about serious issues before relying on it.

Questions

How much does NSSM cost?

The NSSM plan is listed as free.

Which operating systems does NSSM support?

The site says it should work on Windows 2000 or later and provides 32-bit and 64-bit binaries.

What happens when a monitored application exits?

NSSM can restart it, ignore the exit, exit itself, or exit uncleanly to trigger service recovery actions.

Is NSSM open source?

NSSM is public domain, and its source code may be used for any purpose.

Who made NSSM?

The NSSM site identifies Iain Patterson as its author.

How can users troubleshoot NSSM?

The site directs users to the Windows Application Event Log. It also points to the author's email address in repository commits for bug reports.

Facts from NSSM's own pages

Build and distribution: The site says NSSM is built with Jenkins and that its Chocolatey package is maintained by a third party and may not match the latest site build. · nssm.cc, 4 Oct 2026
Exit behavior: When an application exits, NSSM can restart it, ignore the exit, exit itself, or exit uncleanly to trigger service recovery actions. · nssm.cc, 4 Oct 2026
Known issues: The bugs page lists version 2.24 issues affecting newer Windows service startup, Windows XP crashes, log rotation over 4 GB, and other cases. · nssm.cc, 4 Oct 2026
License: NSSM is public domain and may be used with its source code for any purpose. · nssm.cc, 4 Oct 2026
Logging and I/O: NSSM logs its progress to the Windows system Event Log and can redirect the monitored application's input and output. · nssm.cc, 4 Oct 2026
Maker: The NSSM site identifies Iain Patterson as its author. · nssm.cc, 4 Oct 2026
Other controls: NSSM can set an application's priority class and CPU affinity, and can start, stop, and query services. · nssm.cc, 4 Oct 2026
Output rotation: NSSM can rotate output files when they reach a configurable size, including while the application is running. · nssm.cc, 4 Oct 2026
Purpose: NSSM runs an application as a Windows service, monitors it, and can restart it if it exits. · nssm.cc, 4 Oct 2026
Release status: The page lists version 2.24, dated 2014-08-31, as the latest release and a 2.24 prerelease build dated 2017-04-26. · nssm.cc, 4 Oct 2026
Security and privileges: NSSM requires administrator access to manage services, and the site warns that bugs can cause severe system issues. · nssm.cc, 4 Oct 2026
Service setup: It provides a graphical interface for installing and removing services, and its command-line options can configure services from scripts. · nssm.cc, 4 Oct 2026
Support: The site directs users to the Windows Application Event Log for troubleshooting and to the author's email address in repository commits to report bugs. · nssm.cc, 4 Oct 2026
Windows support: The download page says NSSM should work on Windows 2000 or later and includes 32-bit and 64-bit binaries. · nssm.cc, 4 Oct 2026

Where NSSM stands on Freedom251

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