You've probably heard of Railo. Railo is an open source CFML engine. The latest prerelease version, 3.2, is mostly compatible with Adobe ColdFusion 9. Railo is very fast, has a small memory footprint, provides great management tools, and is free. You can purchase paid support plans from Railo, as well as excellent training and consulting.
I love Adobe ColdFusion. If you've already standardized on ColdFusion 9, don't plan significant growth, or are not doing much new development, or have a close relationship with Adobe, Adobe ColdFusion may be the better choice. I don't recommend Railo to everybody. However, there are a lot of good reasons to consider Railo as well. Many of them are documented at http://www.getrailo.org/index.cfm/why-railo/for-cfml-developers . Following is an example of how I used Railo to solve a client's needs.
How I used Railo to solve a client's challenge
One of my clients provides web-based software that is installed at their clients' locations. This software typically runs on a volume license of ColdFusion 7 that my client purchased years ago. There hasn't been any compelling reason to upgrade to ColdFusion 8 or 9; the site runs fine on 7, and it's just not worth messing with a large number of installations of the software all over the world to upgrade all the sites to a newer version of ColdFusion.
However, more and more of my client's clients are wanting to deploy on Windows 2008. ColdFusion 7 predates Windows 2008, doesn't officially support Windows 2008, and basically won't install on IIS 7. This is where Railo came to the rescue. In less than a day, I was able to port the application from CF7 to Railo 3.1. We are now able to deploy client installations on Windows 2008, using Railo. This has made a lot of my client's clients happy, which makes my client happy, which makes me happy.
Six reasons to use Railo
These are some of the benefits that I and my clients have found with using Railo.
1. Cost. Adobe ColdFusion costs between $650 to $7,500 (or more) per server. Railo can be free. There are of course costs beyond the license, but Railo can provide an upgrade path towards a more modern development environment than your old version of ColdFusion, without the license cost.
2. Standardize your environment. Some companies have production servers in ColdFusion 7 & 8, development in ColdFusion 9, and possibly no test or staging environment at all. Fragmented development, test and deployment environments lead to buggy software as inevitable you'll end up doing something like using someVariable++ instead of someVariable = someVariable + 1 in your code which will work in development but not in production. Standardizing on Railo lets you write more reliable code without spending thousands of dollars on more ColdFusion licenses.
3. Separation of sites on a server. ColdFusion Enterprise allows multi-instance usage, which works well for $7,500 per server. Railo offers the capability to run multiple sites in their own sandbox in a manner that so far I find more flexible and useful than ColdFusion's multi-instance setup. This is one reason why many ISPs (like Alurium which powers this site), as each client can have their own web administrator and set up DSNs, mappings, debugging settings, etc.
4. Features. Most of my clients are still running ColdFusion 7. When you compare CF7 to Railo, Railo offers a whole lot of features that make development faster, and in turn cheaper. Last week I converted another client's site from ColdFusion 7 to Railo. I think I had to change two lines of code. I can now take advantage of Railo's built-in ORM and very awesome caching tools, amongst other features. Additionally, their site now runs faster than it did under ColdFusion 7, which is an added and very welcome bonus.
5. Cloud deployment. ColdFusion Enterprise provides a license for up to 10 cloud deployments. That's great, bringing the cost of licensing down to as little as $750 per deployment. With Railo, you don't have to worry about licensing. Your application can go from one instance to three hundred of them without having to place an expensive call to anybody to purchase more licenses. I'm currently working on a project where there could easily be hundreds of Amazon EC2 instances spun up at any time, on demand. I can use Railo as an application server on every single one of those if I want to, without any worry.
6. Approachability. Railo is a small company. The team is approachable. If you post a question on the Railo mailing list, you'll often get an answer by one of the actual developers of the product. It's easy to become part of the process of defining what Railo should be, compared to Adobe ColdFusion. This point can be seen as a negative as well, as some companies will view migrating to Railo as a risk compared to sticking with Adobe which might be seen as more stable. Nobody knows the future, but the counterpoint to this argument is the consternation about what the idea of Adobe "merging" with Microsoft would pose to ColdFusion-based companies. I'd bet that if something like this happened, ColdFusion would go the way of FoxPro. Even if Railo packs up tomorrow, someone else will likely take over the project as it's open source. Railo does offer professional support contracts, which I'd recommend if this is at all a concern to you. Paying for support will ensure that you get extremely highly qualified people to help you out, and it will provide revenue to the Railo team as well.
OK, so a lot of those reasons do spring back to cost. If cost is no issue, you can do most of this with Adobe ColdFusion. However, even in these cases Railo can be a better choice due to its hassle-free licensing, multi-site configuration options, and other features. If you'd like to discuss how Railo might be able to help your business run better, please let me know.