The Obama administration will reveal Sunday if promised improvements to the glitch-ridden HealthCare.gov website have worked, with those tasked with carrying out the fixes seemingly confident of success.

Speaking Saturday, officials indicated that a last-minute push — during which computer technicians worked around the clock — meant that the government would meet a self-imposed Nov. 30 deadline to drastically better the performance of a website at the center of President Barack Obama's signature piece of domestic legislation, the Affordable Care Act.

But a seemingly delayed briefing on the status of the website — now planned for Sunday at 9 a.m. EST, a day later than initially indicated — gives some insight to the frantic behind-the-scenes work that may have been involved in meeting the deadline. Moreover, some questions remain about the reliability of the fixes and the accuracy of the administration’s claims of success.

According to The Washington Post, officials say the site’s capacity has been expanded to handle 50,000 users at once, but the administration has not met all of its internal goals for completely fixing the site and it won’t be clear just how solid the improvements are until more people attempt to use the federal health-care website.

Any leap in performance of the website is likely to be talked up by a White House, especially given the disastrous rollout of HealthCare.gov. The federal website is seen as crucial in the success of Obama’s health care reforms. Once up and working properly it is hoped by the White House to encourage millions of uninsured Americans into finding affordable health care coverage.

But since launching on Oct. 1, it has been plagued by errors, outages, and slow speeds.

As criticism over the botched rollout continued, the administration promised five weeks ago that by Nov. 30 it would fix HealthCare.gov.

And on Saturday, officials involved in that process were indicating that they had made strides in solving the problems.

"We're on target to meet our stated goal for the site to work for the vast majority of users," said Aaron Albright, a spokesman for the Centers for Medicare and Medicaid Services (CMS), the agency responsible for the website. The CMS added that 90 percent of website users can now create an account on the system.

But some information technology experts said the metric cited by the agency was misleading, noting that a claim of anything below 100 percent success was impossible to verify.

"It prevents anyone from the outside from contradicting them," Jonathan Wu, co-founder of the consumer financial website ValuePenguin, told Reuters. He said only those working on the website know whether the 90 percent figure is accurate.

And there has been little insight given on how well the website works beyond the first step, where users choose a password and enter an email address.

A better performing website is seen as vital in helping rebuild public confidence in landmark health care reforms.

In an interview Friday with ABC’s Barbara Walters, Obama said he was confident that Americans would find the controversial law more favorable over time.

“I continue to believe, and [I am] absolutely convinced, that at the end of the day, people are going to look back at the work we’ve done to make sure that in this country you don’t go bankrupt when you get sick, that families have that security,” Obama said. “That is going be a legacy I am extraordinarily proud of.”

The administration has invested enormous political capital in making so-called Obamacare work and there are high stakes given that many of the president’s Democratic allies head into congressional elections next year.

Work on fixing the troubled site has been happening around the clock in the “war room,” a command center in, Columbia, Md. run by QSSI that is known internally as the Exchange Operation Center, or X.O.C., according to The New York Times.

Since the team started working on fixing the site, they have “knocked through well over 300 bugs,” Jeffrey Zients, the former acting director of the Office of Management and Budget tasked with overseeing the project, told The Washington Post.

Still, the risks from not sufficiently improving the website, and fast, are high.

If the website does not work for the "vast majority" of visitors this weekend as the administration has promised, uninsured Americans could face problems getting coverage by an initial December 23 deadline.

It also could create ripples that extend to the 2014 elections when control of the U.S. House of Representatives, now dominated by Republicans, and the Senate, where Democrats have a majority, will be up for grabs.

Congressional Democrats facing re-election already have shown signs of distancing themselves from the president and his health care program. If the website does not show significant improvement soon, some Democrats might call for extending Obamacare's final March 31 enrollment deadline for 2014.

The health care law’s success is also reliant on enrolling millions of young, healthy consumers, whose participation in the new insurance exchanges is key to keeping costs in check.

The administration is also planning on changing its web-hosting provided from Terremark, a Verizon subsidiary, to Hewlett-Packard in the spring according to The Wall Street Journal — a complex change that could present new hurdles and take months to complete.

The site also still does not have its own backup system in place, according to The Journal, but additional server hardware and monitoring software has been added to try and mitigate some of the issues.

The website could be placed under further stress be an anticipated major spike in applications towards the end of the year - insurers have been informed they must find ways to process applications that arrive as late as Dec. 23 instead of the Dec. 15, so people can have coverage by Jan. 1.

“I don’t know if the system will be able to support all of that,” Kevin Lewis of Maine Community Health Options told The Wall Street Journal.

On Friday evening, ahead of the self-imposed Saturday deadline to get the insurance shopping website working, CMS announced it was taking it down for an unusually long 11-hour maintenance period.

CMS is slated to take the site down again between 1 a.m. and 5 a.m. EST on Sunday to perform more upgrades. It will provide the last opportunity for last-minute fixes before Zients faces reporters on Sunday morning to update them, and Americans as a whole, on just how robust the website has become.

Dexter Mullins contributed to this report. With Al Jazeera and Reuters