The Campaign Finance API makes structured campaign-finance data from the Federal Election Commission available via the Internet, so that it can be used to build web, mobile and database applications.

The API provides both timely information like which committees filed today, but also historic information that can help answer the question of how much a candidate raised in the same period of time four years ago.

Users get a key to access the API, and they can request different kinds of information about candidates and committees, including summary financial information and specific transactions. Documentation for the API, including how to get a key, is here.

Q: Why did you build it? What’s the major need for it?

Our API exists to provide data for making web applications that can provide details about how candidates and committees are faring on the fundraising front. Since this is public data, it only makes sense to make it available to everyone.

The FEC has done a great job of making bulk data available to reporters and researchers for decades (and recently launched an API of its own). But our tool has an advantage in terms of timeliness. Data can be retrieved minutes after committees file their reports with the FEC, rather than waiting for the next day or week for the FEC’s official databases to be updated.

Q: How has it been used thus far?

While The New York Times hosted the API, it provided data for both deadline reporting and long-term project research, and gave reporters the ability to get alerts about significant updates or filings. It was used in interactive graphics during the 2012 campaign, and for ProPublica’s PAC Track application.

At ProPublica, we launched FEC Itemizer, which provides a real-time feed of electronic filings that include financial summary data, so you can easily see who filed today and how much money was raised and spent.

An earlier version of Itemizer provided me with many leads as a reporter. I doubt I would have written about the mysterious Virgin Islands GOP committee had I not noticed it in Itemizer.

Q: You frequently tweet fun little nuggets that come through in candidate’s campaign-finance filings. Any favorites?

There are the patently silly ones that clearly aren’t serious, but I think my favorites are ones are the ones I see repeatedly.

Lyndon LaRouche’s PAC still raises hundreds of thousands of dollars a year (and sometimes loses some), and it always brings a smile to my face.

I also like connecting the dots. Recently I found a $100,000 donation to a super PAC last year, which turned round the next day and gave $100,000 to a super PAC backing Marco Rubio’s presidential campaign.

Q: What do you think are big unanswered questions that journalists or scholars could address using these data?

Many reporters and researchers are very skilled at explaining the current state of things or the newest innovation, but I’d also like to see more about how the behavior of filers changes over time. Are the ways that expenditures are described changing since the advent of super PACs, or can we be faster in spotting new trends in fundraising and spending?

I also don’t think we’ve done a great job of mapping finance networks, among donors, vendors and people who run political committees. And if others have questions they want to tackle, I’d love to hear from them if we can make it possible for the API to be a part of that process.