A 22-year-old who once pitched Justin Caldbeck has built an anonymous tool for rating investors

And then he read that another famous investor, 500 Startups' Dave McClure, admitted to being a "creep" towards women.

"I've actually gone through 500 Startups," Zhang told Business Insider. "I knew Dave McClure personally, and had pitched Justin a few times."

Zhang went through 500 Startups with his food delivery startup EnvoyNow, which he then sold to JoyRun for an undisclosed amount.

It troubled Zhang that he knew these investors, but knew so little about their bad behaviour.

"It was a complete blindside to not know that side of their character ... before pitching them," he said. "I got to talking to other founders and sharing stories. Lots of [stories] showed behaviour that was very biased, or flat out disrespectful. Like having five meetings, being really interested, requesting lots of information, then never calling again."

His solution? A kind of Glassdoor for VCs where, instead of rating places of employment, people rate investors.

Zhang has spent the last month building Know Your VC, a platform where founders can anonymously or publicly submit reviews and comments for any investor.

Founders who want to leave a review or comments need to sign up (and be verified by Zhang's team). For now, anyone can search for and read reviews for any investor.

This is one of the reviews that shows up if you search for Justin Caldbeck.

There are some obvious gaps here. There's nothing here flagging the allegations against Caldbeck, or the fact he's stopped investing for the time being. It's the same for Dave McClure, who resigned from 500 Startups. Zhang said his team plan to add tags that will flag negative news coverage, and whether the person is still an active investor.

While founders can submit open reviews, they can also ask to submit comments privately in a kind of personal log. They can then ask to be alerted if someone else submits something similar about the same investor. For a female founder hesitating about whether to go public about harassment or discrimination, that could provide important support.

Zhang is also hoping to add an anonymous chat function so founders can swap tales through the platform, but that's a way off.

He's already had to deal with at least one VC trying to trash another's reputation.

"We have filters and flags for when, say, five emails get created and they all review one person poorly," he said. "We can tell who's signed up. We had an address bashing one VC but could see on their LinkedIn that they were interning for another VC firm."

Still, defamation seems like an obvious problem, particularly since investors rely heavily on their networks to strike new deals.

For now, Zhang is relying on the company's terms and conditions, which stresses that users are responsible for the truthfulness of their reviews. And he said no one's complained about negative reviews yet.

There's a team of five behind Know Your VC, who are building out the platform in their spare time. Zhang said there are almost 1,000 reviews on the platform, and "a few thousand" founders and investors using the platform already.

It's already spread to Europe. Business Insider heard about Know Your VC from an early stage, British female founder, who thought the project was broadly positive. Though she also likened it to a particular episode of dystopian drama "Black Mirror", where people rate each other every few minutes with their phones.

Harry Stebbings, a young British VC who has cofounded a new investment fund with Fred Destin — an investor accused of inappropriate behaviour — is an early adopter for the service. He told Business Insider: "It is incredibly hard for founders to know the right VC for them and so any product that brings transparency to the market will be welcomed by the entrepreneurial ecosystem."

While there are existing resources for founders such as AngelList, there aren't any platforms that vet angels or investors publicly. Most founders rely on private networks and groups to share information. Ultimately, that's probably still the best way for founders to get the most candid views on an investor, but Know Your VC is a good first step towards transparency.

For now, Zhang's focus is on growing Know Your VC and on quality. "If it becomes the Glassdoor of VC, that would be amazing," he said.