Three Carnegie Mellon Ph.D. candidates devise way to track dollars

It’s a common situation among roommates: Having just received a bill for this month’s utilities, everyone tries to figure out how much is owed and who owes what.

After seeing this same situation continually occur, three Ph.D. candidates in Carnegie Mellon’s computer science department decided to do something about it.

Traditionally, roommates have broken out trusty pen and paper to try to figure out the money situation, but by the time that happens the bill can already be past due. But Ashwin Bharambe, Amit Manjhi, and Shashank Pandit turned to technology instead. The three designed to keep track of expenses.

“It started as a personal thing, a set of scripts, then people started asking us for copies—friends, friends of friends, until we finally decided to build a website,” Bharambe said.

The online tool is free and is designed to maintain transactions and personal finances. Many similar sites exist, but what makes Buxfer unique, and what constitutes 70 percent to 80 percent of its use, is the ability to create group transactions with other users and the fact that one can keep track of these transactions easily.

“We tried to make this site very simple and very usable for the common cases,” Manjhi said.

The website’s interface is similar to Google’s Gmail service, complete with associated functionality and ease of use. Almost every transaction field is able to handle the most common transaction types, allowing users to create new transactions with little more than a description and an amount. Users can also associate other users with the transaction.

One click later, all members of the transaction are notified via e-mail, all totals are updated, and the transaction is viewable and editable by anyone who was involved.

“When you enter transactions, a bunch of stuff gets taken care of automatically,” Bharambe said, highlighting a definite advantage over the traditional Post-It or notebook paper method.

The system assumes that groups are familiar with each other, and in keeping with the spirit of ease and simplicity, does not require group confirmations for new transactions; however, a transaction can be edited or even “reversed” (cancelled) by those affected by it if necessary.

Since no actual money is exchanged, there is little potential for transaction abuse by users.

User data and login information is protected and encrypted by standard procedures such as Secure Sockets Layer (commonly known as SSL) to ensure privacy and security. Also, the entire system is run on a web-hosting service using standard open-source applications, so there is no concern over third parties acquiring and using sensitive proprietary information.

The site requires users to register for a username and password, but for those who do not want to create a separate Buxfer account, the site offers integration with Facebook login information.

The Buxfer team plans to integrate the site with automatic payment services such as Paypal, and provide support for transaction deletions. The group is highly open to suggestions from its user base, and is constantly updating and modifying the service based on feedback.

“Unless you start using the website, you don’t realize how easy it becomes,” Manjhi said. “We urge users just to try it out.”