Whether you host your app on your own servers, rent servers from a hosting provider or even can afford a CDN - you probably want to know, how performance looks on distant locations. Is there any way to measure website performance in Asia, Europe, on the other side of the continent (or the world) without beeing there?
Frankly this type of monitoring (geographically dispersed) is most often requested by pointy haired bosses. Measuring is great if what you're measuring is realistically under your control. If your app is slow in Outer Mongolia, are you going to upgrade the internet backbone there? Or go upgrade the users dialup modem?<p>Only pay the extra to measure response time from say, china, if you have a target response time in mind, money, and a plausible plan to improve it if it does not meet the target. Otherwise, spend the money on making your app faster by load testing and scaling it locally and paying for a reliable, professional host. This is not to say don't monitor--you need to watch relative response times and downtime, but the services you're describing cost a lot more, and buy you very little.<p>Edit: Also, I strongly suggest transactional monitoring. If your monitor plays a transactional script (add to cart, checkout, etc) as opposed to a simple page request and you monitor the returned content, you will be able to catch all sorts of errors that are missed by simple page checking. (someone kicked the database ethernet cord out, db lost connection, etc),
It depends on what you mean by app performance.<p>The company I work for (www.alertsite.com) provides basic site/service monitoring that is great for measuring basic infrastucture performance like: DNS, TCP conn, First byte, and HTML content.<p>We also offer measurement from the web browser that shows an incredible amount of detail about every aspect and object on the page. We call this service DejaClick and it is available for free on the desktop (www.dejaclick.com).<p>DejaClick is great for transactional monitoring that can visit your site, run a search, view information, login, etc.<p>DejaClick monitoring for a web application provides the most authentic view possible of website performance as it is measurement from the web browser.<p>Ken Godskind
www.alertsite.com
Keynote and Gomez are two of the most common ways to measure app performance. You can select the number and location of agents you want to test from based on your app's geo market.
Try webperform. They were purchased by Gomez, but basic remote testing is free:<p><a href="http://www.webperform.com/" rel="nofollow">http://www.webperform.com/</a><p>Most frontend optimizations will help everywhere, so as ericb says, do those first. We turned on a CDN (Panther) and used this service and some others from Gomez to test the results.