Lightweight
application monitoring
that automatically diagnoses server problems!

Developed by ex-Microsoft engineers specifically for Windows Server, IIS, and ASP.NET.

Troubleshoot most IIS and ASP.NET problems with LeanSentry's expert diagnostics!

Use LeanSentry to troubleshoot it in minutes!

Troubleshoot an IIS hang →
Fix an ASP.NET memory leak →

We were seeing severe hangs on our ASP.NET site.
Looked at what LeanSentry said was the cause of the hang,
disabled that code, and it’s been smooth sailing since.
- Thomas Nielsen, CEO, Progressive Media (see customer reviews)

1. Detect and instantly diagnose most IIS and ASP.NET issues in production.

Detect most IIS and ASP.NET production issues: errors, hangs, crashes, memory leaks.

LeanSentry watches your apps 24x7
and alerts you about:

Website hangs
Memory leaks
Apppool crashes
IIS/ASP.NET errors
High CPU
Slow requests


When a IIS/ASP.NET hang happens, LeanSentry will automatically debug it and identify its cause.


LeanSentry automatically diagnoses most production issues in the background. No waiting to reproduce, no painful debugging.
Troubleshoot and diagnose IIS and ASP.NET hangs

500 users in 4 months! Here is what they say:

In the first 3 weeks of use, we resolved 3 production issues affecting performance and availability. LeanSentry is now our go to tool for insight into how our applications are running.
- Steven Berkovitz, Platform Architect, OrderDynamics
Great product & company to work with. Ex MS guys who know IIS and the MS stack. You work with the team directly, not a customer care layer. LeanSentry uncovers things in minutes vs. days of digging.
- Dan Foxley, IT / Operations Manager, Pacific DataVision

2. Lightweight and non-intrusive monitoring with standard Windows protocols.

Maintains incredibly low overhead.

LeanSentry uses low-impact Windows protocols to monitor your applications, including IIS logs, Peformance counters, ETW tracing, and WMI.

Never loads third party code or profilers into your application.

Never collects sensitive data or code.
Deploy anywhere - AWS, Azure, or your own environment.

Deployment that makes sense.

LeanSentry can run on a separate VM in your environment, and monitor your production servers remotely without installing anything on them.

Deploys in < 5 minutes.

Works in Azure and EC2.


You could say we wrote the book on IIS.

The IIS 7.0 Resource Kit book
Mike Volodarsky founded LeanSentry after working on the IIS 7.0 and ASP.NET 2.0 products at Microsoft. Our story.

LeanSentry is based on tools and techniques developed while working with some of the largest Microsoft-based websites in the world, including MySpace, Vevo, Microsoft mobile, and hundreds of others. Take our production troubleshooting course.

3. Track application health and troubleshoot performance like an expert.

See every slow and failed request.

Track health of every URL.

Track the health of every URL.

Track application memory and CPU usage.


Track application memory and CPU usage

See every IIS, ASP.NET, and server error.

LeanSentry groups related errors, and identifies new and abnormal errors to review first.

Fix errors quickly with IIS error explanations and ASP.NET exception stacks.
See every IIS, ASP.NET, and server error.

Users love LeanSentry because it makes things simple:

This is a fantastic product. We were able to improve speed noticeably on a horrow-show of a server. Seriously, this is really good stuff... you're going to make a hero out of me.
- Dan O'Connell, Senior Developer, Millstone Medical
I have not seen a service that provides so much information with so little setup. LeanSentry made it simple to diagnose errors and slowdowns, and gave us a way to measure our success in resolving application issues.
- Ed W., Web Developer, InfoTrack