The Ukrainian-born entrepreneur minted his reputation as somethingof a Silicon Valley superstar after co-founding the online payments service PayPal in the late 1990s. Levchin served as PayPal’s chief technology officer for four years, during which time he built the complex software that kept the Website operating while staffing up the engineering team. All the effort paid off big when eBay EBAY acquired PayPal for a cool $1.5 billion seven years ago (He reportedly banked $34 million.) Afterwards, Levchin had five-year run heading up mobile game maker Slide before selling it to Google, where he briefly served as vice president of engineering.

But for the last two years, Levchin has tried reinventing online payments, much the same way he did with PayPal. His latest start-up, Affirm, tackles consumer loans, but with a twist. Generally speaking, it’s a substitute for credit cards. “It turns out theres lots of data there about someone, and a lot of it is completely relevant,” explains Levchin.

Here’s how it works: Customers ofonline retailers that partner with Affirm partner can choose SplitPay as an option when they’re about to buy something. To determine eligibility, Affirm weighs tens of thousands of different bits of information about a person. Traditional credit approval usually relies on FICO scores, which arebased on five categories including a person’s credit payment history, debt, the length of credit history, any new credit and kind of credit they use. Affirm takes that information into account, plus much, much more like whether an applicant has a Facebook FB profile (which can be helpful in proving someone’s identity) to whether that person has had their cell phone account closed several times (a red flag). The goal is to deduce from such public and private data whether an applicant is worth the risk – a process Levchin says he has improved over the way traditional credit scores are calculated.

Loans can range from tens of dollars to upwards of $10,000, with the interest rate and number of paymentsdecided on a case-by-case basis. Meanwhile, Affirm pays the online retailer the full amount of the customer’s purchase within 48 hours from its pile of $45 million in venture-backed funding. Affirm has just four retailers signed up, including cosmetics retailer Beautylish and Blossom Coffee, but the company expects to announce new partners every week moving forward.

To be sure, Affirm has a lot to prove. There are a number of startups like LendUp and Earnest that are tinkering with the idea of approving loans based on information culled from unconventional sources. Affirm also runs up against other, more established services like Bill Me Later, eBay’s layaway program. It also competes, to some extent, with Lending Club, which bases its risk calculations on the income of loan recipients and has already lent more than $4 billion.

Of course, credit card companies already occupy a huge market. But part of Affirm’s potential appeal lies in its more detailed loan approval process. Because it takes into account tens of thousands of bits of data — versus FICO’S five — applicants who don’t have a long credit history, but may be responsible borrowers, are more likely to get approved.

Affirm is one of two startups that came through HVF, the startup incubator Levchin founded in 2010.Currently, HVF is home to at least at least give such potential startups, or “projects.”

“Its like a mad scientist lab where I invite my mad scientist friends to hang out and sit around and try to come up with something interesting for six or seven weeks,” says Levchin.

Aside from Affirm, the other HVF-funded startup graduate is Glow, a fertility app launched last fall aimed at helping couples conceive by tracking information like a woman’s menstrual cycle and offering health tips based on information users add daily. Four months ago, the company introduced Glow for Enterprise so that businesses could offer their employees more fertility benefits beyond the typical health insurance plan. To date, Glow for Enterprise has signed up tech startups like Evernote, Eventbrite, and data software company Domo.

So whileLevchin remains busy with multiple projects, he’s focused on taking Affirm mainstream and enjoying the daily minutiae of being CEO. Says Levchin, “I realizedthat running a company is something that I missed and really enjoyed.”

Launchedon Monday, the new feature, which is within Amazon’s “Login and Pay” service launched last fall, allows over 240 million customersto use saved credit card information to pay for monthly services, including phonebills and music streaming.

Amazon AMZN will make money from a fee on each transaction.

Ting, a mobile carrier and mobile product provider, was the first company to use the new feature in a test over the last few months. They“experienced pretty impressive results in the first few months,” according to Amazon, “including high conversion rates – customers choosing to use Amazon over other payment methods.”

The service is expected to allow customers to more easily track theirpayments as well as provide “trust and security” for customers seeking added protection.

“You should see it as one of many things that we’ll do to expand where people might think about Amazon helping them,” Tom Taylor, Amazon vice president of seller services, toldReuters.

The news comes ahead ofa mystery June 18 announcement by Amazon during which the e-commerce giant is expected to unveil asmartphone. The device wouldwidenAmazon’s role in mobile payments for customers.

Patrick and John now reside in San Francisco, where they founded Stripe, a company that has come to be a disruptor in the global financial system. Stripes technology allows businesses to circumvent the complexity of currency exchanges with online payments, enabling them to sell products or services to anyone, anywhere, in minutes. Stripes 80-member team is growing and has raised more than $40 million in funding from investors like Andreessen Horowitz, Sequoia Capital, and PayPal founders Peter Thiel, Max Levchin, and Elon Musk.

Collision, an avid reader and programmer, spoke to Fortune about what technology entrepreneurs and companies he finds most admirable, his laundry list of recently read books, and how to do important work.

1. What business or technology person do you admire most? Why?

In technology, I sorta see people in two camps — the visionaries like Douglas Engelbart, Ted Nelson, Alan Kay, and J.C.R. Licklider who inspired others to do amazing things, like create the web or the Macintosh or whatever, and the implementers like Linus Torvalds, Dennis Ritchie, Vint Cerf, or John Carmack who’ve pulled off incredible technical accomplishments.

I’m still not sure which group is more important. I guess you need both. There are also a few individual people, like Fabrice Bellard, Jeff Dean, and Dan Bernstein, who are just generally fabulously productive and make me feel guilty about how little I get done. I couldn’t pick one person. In general, I have a bias towards people who think about and have built basic infrastructure. It’s informed a lot of our thinking with Stripe.

2. What other companies do you admire? Why?

I admire companies that use time horizons as a competitive advantage — doing things that pay off over a longer timeline than competitors are willing to wait; companies that still do hard, basic research; companies that manage to pay attention to the details even when they’re big; companies that manage to retain a specific mission that’s broader than their business; and companies that try to figure out how an industry should work from first principles.

3. Is business school necessary for entrepreneurs?

I can’t, offhand, think of a great entrepreneur who went to business school.

4. What is the best advice you ever received?

“If you do not work on an important problem, its unlikely youll do important work.” That’s from You and Your Research by Richard Hamming, which is a generally good source of life advice.

5. What would you do if you werent working at your current job?

Probably trying to build or discover something useful somewhere else. Or in a cabin, reading books.

6. What technology sector excites you most?

Software is still fairly early in the process of both systematically rearranging other industries and enabling fundamentally new things, and I’m excited by the ways in which we can help facilitate that. What’s happening in energy, education, health care, biotechnology, and so on — especially the intersection between those fields and software — is also fascinating.

I don’t think it’s really accurate to look at software as a “sector;” software and the Internet are increasingly the atmosphere in which every other business exists.

7. What was the last book you read?

Creating the Twentieth Century by Vaclav Smil — highly recommended — and just before that, Powering the Future by Robert Laughlin, which was also pretty good. The best two books I’ve read this year are The Art of Doing Science and Engineering by Richard Hamming and The Dream Machine by Mitchell Waldrop.

8. What do you do for fun?

Cycling, running, reading, programming.

9. What is one goal that you would like to accomplish during your lifetime?

Read all the books.

10. What was your first job?

A friend and I tried to start a technology company when we were 13. It didn’t go very far. I blame market conditions.

More from Fortune‘s 10 Questions series:

• DAQRI CEO Brian Mullins: ‘4D excites me more than anything’
• Scopely CEO: To excel at business, create a narrative
• Polyvore CEO: To succeed, write ‘good, clean code’
• Annie Longsworth on the one trait every leader needs
• Tony Fadell on practicing what he preaches