The stress-free process left Haagh wondering how she could make finding a trustworthy babysitter easier for Kiwi parents.
"It's quite a common parenting problem finding a source of reliable and trustworthy babysitters," said Haagh.
So, the former marketing manager got together with parents from her son's school and asked them to recommend babysitters they had used, for the new online service.
"I understand that [leaving children with a babysitter] can be quite an emotional transaction for parents because I'm a mum and I'm quite careful who I leave my children with. But I felt that if [the babysitter] had been recommended by a friend or someone at school then I would feel better about hiring them," said Haagh.
"Another parent's recommendation really does hold quite a lot of weight."
Sitterzen allows parents to scroll through a list of babysitters trusted by other parents and have someone at their door in as little as an hour.
If a babysitter wants to join the website, they must be recommended by a family who they have babysat for at least twice in the past. Then, information including their photo, a short description, age, rate, experience and availability will appear on the website.
The site also provides users with the ability to contact parents who have recommended a babysitter before they make a booking.
Sitterzen doesn't currently police vet babysitters. However, Haagh said if parents asked them to start carrying out police checks she would be happy to do so.
Sandringham resident Annabel Hurman has used Sitterzen twice and said the lack of police vetting didn't worry her.
"Police vetting is not something that I would have routinely done for babysitters that I've used in the past," said Hurman. "If they were recommended by a friend, [carrying out police checks] wouldn't have even crossed my mind."
Hurman said she found Sitterzen made finding a babysitter "really easy" and liked that her two kids could read about the sitters before she booked.
Since Sitterzen started taking sign-ups in August, 24 babysitters have joined the website.
The service has also expanded from Balmoral into Mt Eden, Mt Albert, Mt Roskill and Sandringham.
While Haagh would like to see Sitterzen become available nationwide, she is focused on making sure it doesn't grow too quickly.
"It's growing quite organically. I'm happy to keep going the way we are going now and build the technology required to create quite a seamless solution based on our customer feedback".