Peanut adopts the format of dating apps such as Tinder where mothers upload profiles and pictures and "swipe" to register their interest in each other.
Co-founder Michelle Kennedy was deputy CEO of European dating app Badoo and was also on the board at Bumble.
It is one of a growing number of apps aimed at helping parents to build connections.
Ms Kennedy said she was disappointed by the digital services available to new mums wanting to chat with others when she became a parent herself.
"I had been working in tech for a long time, I felt I had this level of expectation about the type of product I could use," she said.
She said many of the mobile apps had poor user interfaces, and the traditional chat forums felt old-fashioned and alienating.
"I felt really frustrated by the tone of language, it wasn't something I recognised," she said.
"Lots of abbreviations I was Googling - DS [darling son], OH [other half] - it felt really weird. I felt immediately like I had aged."
Peanut is free to use and for the moment the focus is on building a community rather than accepting advertising - but that is not being ruled out in the future.
Mothers upload a profile and choose three badges which best describes them - including 'single mum', 'sleep deprived' and 'spiritual gangsta'. But the platform uses machine learning to work out what else mothers have in common with each other and what is a priority for them in order to match them.
Ms Kennedy says many women are already familiar with the dating format.
"There's this entire generation of women who met their partner on a dating app," she says.
"The tech is there - why hasn't it been accessible to us to use?"
There is a growing market place for this type of introductory platform for parents, such as the Bubble app which hooks up parents with recommended babysitters, and Koru Kids which connects those seeking to share a nanny with those who have a nanny to share.
Sarah Hesz and Katie Massie-Taylor founded the mums' platform Mush in April 2016, and the app has so far had around 60,000 downloads and been used one million times, they say.
But it does not have a swipe format.
"It's more about browsing local mums based on your interests," said Ms Hesz.
"It's not about rejecting people."
Mush is also free to use but they have worked with "brand partners" including Johnson & Johnson and Unilever.
"We don't have a tech background - we've learned not to be afraid of that, we can manage a team of developers," said Ms Hesz, who said she met Ms Massie-Taylor in a playground and exchanged numbers with her because she was "desperate for adult conversation".
Parenthood, especially in the early days, can be a very lonely experience, she said,
"Mums are not very good at being open about the fact that we need friends," she added.
"Some of our users are making friends for life, others are just trying to make the day better."