Some of the biggest players in the U.S. tech industry are writing big checks for the Democrat challenging Rep. Mike Honda (D-Calif.), helping the newcomer to a huge fundraising edge over Silicon Valley’s longtime congressman.

Former Obama administration official Ro Khanna (D) raised a whopping $1 million in the first three months of his campaign against Honda, a substantial haul for a rookie candidate. 

Khanna, who is bucking the Democratic Party establishment in his bid for Honda’s seat, raised almost all of his money from the booming Silicon Valley region he hopes to represent. 

Much of the fundraising haul came from major donors to President Obama. 

They include: Facebook executive Sheryl Sandberg, Yahoo CEO Marissa Mayer, CEO Marc Benioff, Napster founder Sean Parker, venture capitalist Marc Andreessen and technology entrepreneur Mike McCue.

McCue hosted a fundraiser for Obama at his home less than a month ago, and Sandberg, Benioff and others have also previously hosted fundraisers for the president where he was personally in attendance.

Honda raised $345,000 over the same three-month period, his campaign announced Wednesday afternoon. 

It’s a solid total under normal circumstances, but less than a third of what Khanna brought in. 

Honda has $375,000 cash on hand. 

Obama has officially endorsed Honda and Vice President Biden recently made a campaign pit stop for the longtime congressman. 

But those White House endorsements haven’t swayed Obama’s donors to stick with Honda. 

Several top Obama campaign staffers are also working for Khanna, a former deputy assistant secretary at the Department of Commerce who has known Obama since his first campaign for state senator. 

They include Jeremy Bird, Obama's 2012 national field director; Steve Spinner, a top Obama campaign fundraiser who is chairing Khanna’s campaign; and Larry Grisolano, who ran Obama’s paid media efforts in both 2008 and 2012.

Khanna already has $1.75 million in the bank — more than some congressional campaigns raise in an entire campaign cycle. 

According to Khanna’s campaign, he's the first candidate ever to raise $1 million while running against a sitting congressman without self-financing.

"What's clear from the early support I’ve received is that Bay Area voters are frustrated with Congress — and they agree we need to bring Silicon Valley thinking to Washington," Khanna said in a statement. 

"What's especially exciting is knowing we're attracting so many new, young voters and Asian Americans who are not only supporting my campaign but will be involved in the Democratic Party for years to come."

Khanna’s gaudy fundraising numbers come despite Honda having the endorsements of nearly every major Democratic figure: House Minority Leader Nancy Pelosi (Calif.), Democratic National Committee Chairwoman Debbie Wasserman Schultz (Fla.), Democratic Congressional Campaign Committee Chairman Steve Israel (N.Y.), and California Sens. Dianne FeinsteinDianne FeinsteinTrump's Democratic tax dilemma Feinstein: Trump immigration policies 'cruel and arbitrary' The Memo: Could Trump’s hard line work on North Korea? MORE and Barbara BoxerBarbara BoxerTime is now to address infrastructure needs Tom Steyer testing waters for Calif. gubernatorial bid Another day, another dollar for retirement advice rip-offs MORE.

Honda has also been endorsed by actors Kal Penn and George Takei and received donations from Silicon Valley companies including McAfee, Philips Electronics and Qualcomm Inc.

Khanna, 36, faces a tough battle in the Silicon Valley district and will need to keep up his torrid fundraising pace if he hopes to take down the longtime lawmaker.

Honda, 71, has been in Congress for more than a dozen years, and has close ties with the Asian-American and tech communities. He was also a longtime vice chairman of the powerful Democratic National Committee. 

Honda's campaign released a poll earlier this year showing him leading Khanna 57 percent to 5 percent.

Honda spokesman Dan Cohen emphasized a large number of low-dollar donors gave money to the congressman — and can keep giving throughout the campaign.

Cohen also argued Honda was revered by the tech-savvy grassroots supporters in the party.  

Honda was warmly received at the recent annual Netroots Nation gathering of activists that this year took place in his San Jose district, he said. 

“We had just yesterday 100 local elected officials endorsing the congressman. We had Netroots Nation in the district, where the congressman was welcomed like a rock star. And Joe BidenJoe BidenMoore, Strange advance in Alabama GOP primary Alabama GOP Senate primary: live results White House clarifies: We condemn all violence MORE was just in the district, did a stop-by at a coffee shop for Congressman Honda,” Cohen said.

The district is heavily Democratic, giving Obama 72 percent of its vote in 2012. 

But the race won’t function like a normal primary. 

California’s unique “jungle primary” system means the top two vote getters in the primary move to the general election, regardless of party. 

Khanna is making a play for the district’s independent-leaning Democrats and Republican voters as well, opposing a plan embraced by Honda to tax capital gains like regular earnings. 

Some of Khanna’s donors reflect the independent streak Khanna is hoping to show. 

Mayer has also donated to centrist Republicans, while Benioff donated to Rep. Paul RyanPaul RyanGOP chairman to discuss Charlottesville as domestic terrorism at hearing Trump’s isolation grows GOP lawmaker: Trump 'failing' in Charlottesville response MORE’s (R-Wis.) campaign as well as Obama. Andreessen was a Romney backer.

Honda has also rolled out endorsements from Republicans like former Rep. Joseph Cao (R-La.) as well as from Democrats like former House Majority Leader Dick Gephardt (D-Mo.) and former Senate Majority Leader Tom Daschle (D-S.D.).

This story was first posted at 9:20 a.m. and has been updated to reflect that Cao, Gephardt and Daschle endorsed Honda.