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Introducing Union Station: our web app performance monitoring and behavior analysis service; now in open beta

By Hongli Lai on March 2nd, 2011

Web application monitoring: easy, high quality, detailed and low overhead

We are pleased to announce Union Station, our state-of-the-art web application performance monitoring and behavior analysis service. It aids web application developers by helping them to understand their web application’s behavior and identifying bottleneck and problems. It aids system administrators by notifying them of potential problems so that they may react quickly. As a result, it aids organizations as a whole by improving visitor satisfaction. Union Station supports Ruby and Rails web applications through Phusion Passenger.

We have been testing Union Station in private with various parties for some time now. Today we are taking things to the next level by opening Union Station for public beta testing. During this beta period we allow up to 1000 sign ups. This is because we take user feedback seriously and by limiting the number of sign ups we believe we can process feedback better.

Union Station is to become a paid subscription service. We will offer a variety of plans with different features and characteristics. But during the open beta Union Station is entirely free of charge. When the open beta ends we won’t bill you until you’ve explicitly given chosen to pay. The open beta ends when we think we’ve gathered sufficient feedback.

Main highlights and differentiation points


Union Station differentiates itself by being extremely easy to use and to setup. Our web interface is carefully designed for maximum usability. With Union Station, you will not waste time learning how it works and how to make it work only to give up in frustration hours later.

Union Station monitors and indexes many different kinds of information and displays them in a friendly web interface.


Union Station monitors and indexes response times, memory usage, database accesses, cache accesses, web application process histories and request information.

One can browse freely into any time in history (as far as data retention allows) and see exactly what the web application was doing at that time: its processed requests, its memory usage behavior, its application processes, and more.


Union Station is a hosted service that works on a subscription basis. Your data will be sent to us for processing, and we will index it and display it on a slick web interface. Different plans are available with different data retention times and features.

By being hosted, you do not need to install complex software on your servers for processing data, do not need to worry about updating that software and do not need to worry about backing up the data. We will take care of all that.

Important information is visualized in charts and placed strategically to allow easy comparison.


We believe that security should not be a premium feature. Attacking unsecured network connections is now easier than ever with the availability of tools like Firesheep. In order to protect our users, we encrypt all data sent to us through HTTPS and the use of HTTPS for our web interface is mandatory. HTTPS is the same security protocol used by banks and other organizations in which security is of utmost importance. Your security is dealt with the greatest care.


An HTTP/REST application programming interface is provided for querying data from Union Station. This allows you or your IT department to create automation tools that take advantage of the information provided by Union Station.

Relating data

We understand that when things go wrong, multiple sources of information must be consulted. We link related information together so that this job becomes easy. For example, given a request, one can easily query the database actions that were executed and query the web application’s memory behavior during that point in time.

Improvement progress feedback

Union Station also allows one to compare recent metrics with metrics in an earlier point in time, in order to determine whether improvements have had effect.

Clustering support

Union Station fully supports web applications that are clustered over multiple machines. We are able to collect data for each machine in the cluster and display everything in a single web interface.


Don’t find out that your servers are over capacity until it’s too late. Union Station can automatically keep an eye on your resource usages such as CPU usage, memory usage and response times and notify you if things don’t look so well. Notification is near-instant and happens through email, though SMS support is in the works.


Union Station supports multiple user accounts as well as access control. One can easily share web application data with multiple users under a secured environment: the data is only available to those users who have been given explicit accesss. Additional user accounts are free, we only charge for data collection and processing.

Firewall install

We understand that some organizations cannot allow their data to leave their firewalls. Other organizations simply have too much traffic to make sending data to an external service feasible. It is for these reasons that we will also provide a firewall install in the future. Please contact us for licensing details.

Quality through specialization

Union Station requires the newly released Phusion Passenger 3.0.4

We believe in doing few things instead of many things, but doing them very, very well so that we can commit ourselves to the highest product quality. It is for this reason that Union Station currently supports all Rails as well as all Ruby (Rack) web applications in combination with Phusion Passenger 3, but not web applications written in other languages or web applications deployed on application servers other than Phusion Passenger.

The request timeline, a unique feature made possible by tight Phusion Passenger integration.

Union Station support is tightly integrated into Phusion Passenger. This brings the following benefits:

  • Union Station can gather information that other monitoring products can not, such as detailed request timing information.
  • Enabling Union Station support only requires a few configuration lines. There’s no need to install separate plugins or daemons for data collection, greatly reducing installation and setup risk.
  • Many other monitoring products impact the performance of web applications due to the way they collect data. However, Phusion Passenger’s Union Station support is written in carefully coded C++, allowing the highest degree of performance and the lowest possible overhead.
For more information, please visit the Union Station website.
You can also follow us on Twitter @unionstationapp.