Designed for speed and efficiency, SqWebMail works with a wide range of mail servers.

by Jeff Goldman [September 28, 2005]

SqWebMail was originally developed in 1999 by Sam Varshavchik to resolve some of the problems he perceived with procmail. "Procmail lacked some of the things I wanted in my mail filter, such as parsing RFC-822 addresses out of mail headers," he says.

Varshavchik first wrote the mail filter solution maildrop as a replacement for procmail, then realized he was most of the way to creating a webmail server. "A good chunk of what a basic webmail server does is simply parsing messages," he says. "Once the messages are parsed and the webmail server knows what's in them, it's really not that complicated to manufacture some HTML that presents all that data in some meaningful way."

So Varshavchik spent the next few months, he says, building both a webmail server and an IMAP server. The results were SqWebMail and Courier-IMAP. "When I saw where things were going, and that I would eventually have a complete mail server working, I picked a name for it: Courier," Varshavchik says.

Ongoing development
In the years since then, Varshavchik says, the webmail solution has grown significantly. "SqWebMail can now work with maildrop to create simple mail filters from a fill-in-the-blanks Web form," he says. "With GnuPG, SqWebMail offers complete support for encrypted and digitally signed e-mail—SqWebMail can actually offer a fairly well-rounded Web-based interface to GnuPG, including generating new keypairs, signing keys, and exporting or importing keys (as MIME attachments)."

At this point, Varshavchik says he's happy with SqWebMail's level of functionality—he doesn't anticipate any major changes in the near future. "SqWebMail has matured and is now mostly in maintenance mode," he says. "But if I can think of something nifty, I'm going to put it in."

That said, Varshavchik says there's usually a new release, mostly for bug fixes, about once every two or three months. "The releases tend to be more maintenance-related," he says. "Between releases, there are development builds—there usually one every week, on average. When enough fixes accumulate, an official release tarball gets built and released. But in practice, the semi-weekly development builds are stable enough to be used in a production environment."

Speed and efficiency
SqWebMail's key strength, Varshavchik says, is the fact that it reads mail folders directly. "Other webmail servers are really emulation layers that piggyback on top of IMAP," he says. "Other webmail servers do not access the individual mail messages directly—instead, you need to set up an IMAP server first, then the webmail server ends up connecting to the IMAP server and using IMAP to access e-mail."

And most of the time, he says, that slows things down significantly. "In some of the most extreme cases, each HTTP request received from a Web browser client ends up with the webmail server connecting to the IMAP server, logging in, executing one or two IMAP commands, then disconnecting and returning the resulting HTML response to the client," Varshavchik says. "All this happens with every click!"

The fact that SqWebMail doesn't use IMAP, Varshavchik says, makes it a faster and more efficient webmail solution than most. "It typically places only a small fraction of the load on a server that other webmail servers require," he says. "SqWebMail's performance depends more on the performance of the underlying file system where the mail files are kept—it will easily handle mailboxes with thousands of messages, provided that the underlying file system is properly tuned to support large mail folders."

A simple solution
There are no spam or virus filters included with SqWebMail, though Varshavchik says it should work perfectly well with most such solutions. "From its perspective, it's just an ordinary folder, no different than any other folder—and moving messages into or out of that folder is no different than moving messages into or out of any other folder," he says.

For support, the SqWebMail mailing list is an essential resource—and Varshavchik notes that there are a number of vendors offering commercial support as well.

While SqWebMail was obviously created to work with Courier, Varshavchik says it functions well with a wide range of mail servers. "SqWebMail is a fairly popular combination with Qmail and Postfix, in addition to Courier," he says. "Occasionally, you'll find someone using SqWebMail and Sendmail. SqWebMail does not really talk to the mail server that much, so it has very little dependency on the mail server—as long as the mail server delivers mail via some process to the mail folders, and as long as there's a reasonably 'sendmail' command that reads mail from standard input and sends it, SqWebMail will be fine."

— End

Related articles:
	[April 21, 2004]	A Frequently E-Mailed Question
	[May 20, 2002]	IMAP vs. POP3
	[March 2, 2000]	QMail: A Better Sendmail?

Online resource:
	Webmail Directory
	Webmail Quick Reference Chart