Massachusetts’ notoriously opaque state government is about to get more transparent, with the launch of a website detailing state payroll and spending data.

Comptroller Thomas G. Shack III says his office’s site, dubbed “CTHRU’’ and set to go live Sept. 14, will give the news media, public interest groups, and others an important tool to uncover waste and fraud.

“As a [former] prosecutor . . . I’m interested in the truth,’’ he said, in a briefing Wednesday on the new site. “This is a truth machine.’’

The state already has a similar website in place known as “Open Checkbook.’’ And some of what is available on that site, such as spending by quasipublic state agencies, will not appear on CTHRU when it launches next week.

But Shack said his office is moving to add that information. And he suggested that CTHRU — located at Mass.gov/comptroller/cthru — will soon make “Open Checkbook’’ obsolete, providing more information, in a more digestible way, at a lower cost.

“As we expand the system, you’re going to have a whole dashboard of information available to you that was never available to you before,’’ he said.

Shack said he wants to provide detailed information on state contracts, for instance, and make it easy to track spending by vendors’ ZIP codes.

The comptroller’s office built the site, with Seattle-based technology firm Socrata, in anticipation of a new public records law signed by Governor Charlie Baker in June.

The measure requires government agencies to provide records in digital format, where possible. It also puts some limits on what agencies can charge for producing records. And it allows the public to potentially recoup their attorneys’ fees when they successfully sue government agencies for improperly withholding records.

Plenty of barriers to open government remain. Massachusetts is the only state, for instance, where the governor’s office, the Legislature, and the judiciary all claim to be exempt from public records law. But Shack suggested Wednesday that CTHRU will provide a new level of transparency when it comes to state spending, at least.

He offered news outlets and public interest groups a brisk tour of the website.

One section offered detailed payroll information, including a list of the five highest-paid public employees in the state last year, with University of Massachusetts basketball coach Derek Kellogg coming in first at $1.07 million.

Another allowed users to search how much the state is paying vendors like copying giant Ricoh — and to compare the totals with spending by other US governments.

Officials say the site puts a premium on data visualization, with charts and graphs to make the information user-friendly to a broad slice of the public.

The service will cost the state about $175,000 in the first year, according to the comptroller’s office, with the figure climbing into the low $200,000 range per year as new features are added.

David Scharfenberg can be reached at david.scharfenberg @globe.com. Follow him on Twitter @dscharfGlobe.