Here's a preview of what Obama will say in his big DNC speech
Obama is set to focus on Clinton's experience and readiness for the job, a common theme he has sought to tout in contrast to Republican nominee Donald Trump.
Obama will say:
"You know, nothing truly prepares you for the demands of the Oval Office. Until you've sat at that desk, you don't know what it's like to manage a global crisis or send young people to war. But Hillary's been in the room; she's been part of those decisions. She knows what's at stake in the decisions our government makes for the working family, the senior citizen, the small business owner, the soldier, and the veteran. Even in the middle of crisis, she listens to people, and keeps her cool, and treats everybody with respect. And no matter how daunting the odds; no matter how much people try to knock her down, she never, ever quits.
"That's the Hillary I know. That's the Hillary I've come to admire. And that's why I can say with confidence there has never been a man or a woman more qualified than Hillary Clinton to serve as President of the United States of America."
And in another veiled reference to Trump, Obama will paint a picture of optimism for the country, a stark contrast to Trump's speech at last week's Republican National Convention that was widely viewed as a "dark" portrait of the US' near future.
Obama will say:
"The America I know is full of courage, and optimism, and ingenuity. The America I know is decent and generous. Sure, we have real anxieties - about paying the bills, protecting our kids, caring for a sick parent. We get frustrated with political gridlock, worry about racial divisions; are shocked and saddened by the madness of Orlando or Nice. There are pockets of America that never recovered from factory closures; men who took pride in hard work and providing for their families who now feel forgotten. Parents who wonder whether their kids will have the same opportunities we have.
"All that is real; we're challenged to do better; to be better. But as I've traveled this country, through all fifty states; as I've rejoiced with you and mourned with you, what I've also seen, more than anything, is what is right with America. I see people working hard and starting businesses; people teaching kids and serving our country. I see a younger generation full of energy and new ideas, unconstrained by what is, and ready to seize what ought to be."
Obama's speech will come two days after first lady Michelle Obama's rousing address to the convention. Democratic vice-presidential nominee Tim Kaine, former New York Mayor Michael Bloomberg, and Vice President Joe Biden are also set to speak Wednesday.