Kinder Browser Developer Interview: Giving Children Only the Useful Side of the Internet
OBARA Hiroki Ā· DeveloperKinder BrowserInterview
The first commit of Kinder Browser is dated August 10, 2023, and version 1.0 was released on September 19. It is a native app written in Swift, available in 19 languages, and runs on iPhone, iPad and Mac. It costs Ā„1,500 in Japan and $9.99 in the US as a one-time purchase, with no in-app purchases.
Development resumed at the end of January 2025, and version 1.6 added UI Removal Mode, history, Blue Light Cut and whitelisted pages, among other things. I asked hiroki, who made it, about how it started and how they think about it now. The answers are kept as close to the original Japanese as translation allows.
Handing over Safari felt scary
Q. The store listing says it began because there was no good browser for your daughter to use websites for learning.
When I let her use sites like Scratch and NatGeo, browsers like Safari were hard for her to operate, and it felt scary that she could go to other sites when I wasnāt watching. The existing apps were hard to use too, so I made one myself, DIY style.
Q. It took about a month from first commit to release. What was non-negotiable?
Blocking navigation to anything other than the pages a parent allowed was essential. Some of the sites children wanted to see showed ads, so I wanted ad blocking too, but it was a bit hard to implement, so I put it off.
Q. In the first version, the home URL was set in the iOS Settings app.
I wanted the settings somewhere the child couldnāt reach. But that design also made things awkward for parents, so it wasnāt great.
Q. From September 2023 to January 2025 the app was barely touched.
My younger daughter started using it, and I noticed things I wanted to fix, so I fixed them a little at a time.
Like a knife
Q. Unlike apps for drawing, playing or writing, a browser is partly a tool for stopping things.
A web browser is very useful for reaching the vast internet, and at the same time it can be dangerous. A knife can be useful or dangerous depending on how it is used. But if it is designed carefully as something for children, a child can use it safely on their own.
On the web, harmful and useful things exist side by side. I think tools like Kinder Browser, which deliberately put limits on children, are necessary so that children can take in only the useful side of the internet.
Q. Do you ever disagree with yourself, as a parent and as a maker?
Not really. I try to keep it simple and avoid complexity. Even so, early versions felt complicated, and I got negative feedback from users. That kind of feedback stings, but I think it is valuable.
Not allowed unless allowed
Q. Why start from what is allowed rather than listing what is blocked?
I follow a fail-safe approach. The target age is young, so I think the default should be not to allow.
Q. Links within the same site open, and links to another site are stopped.
I thought it was better for children to move freely within a site that has been allowed, so that is how it works.
Q. Without a custom PIN, the parental gate is a multiplication question.
The target age is young, so I think multiplication is enough. As children get older, parents can use a custom PIN.
Q. A US review said that a multiplication problem was all it took to get into an unrestricted browser. It was actually the parentsā search screen, but thatās not how it looked to the user.
Whenever I see reviews like that, I think how deep interface design is. Basically, what users feel is right. I have to design so that it doesnāt mislead.
UI Removal Mode, Web App Mode, Mac
Q. UI Removal Mode, added in 1.6, lets you pick elements on a page and hide them.
I thought it would be good to be able to remove UI elements that get in the way, so I built it.
Q. In Web App Mode you can put the button on the left, centre or right.
Some web apps like Scratch fix elements to the bottom of the page, so this is to work around them.
Q. The screen doesnāt turn off automatically while a page is showing.
Because itās more convenient that way.
Q. There is also a Mac version.
I thought it should properly support Mac, including file saving and microphone permissions, so I developed and released a Mac version.
Graduating at about 13
Q. What do you want the internet to be for children?
A place where they can reach the world. Kinder Browser exists so that even children can use the internet safely.
Q. At what age should a child graduate from Kinder Browser?
Around 13. Legally thatās about the age, too. I donāt think it is good to keep using this app forever.
Q. You make a strong point of collecting no data.
As a user, itās only natural not to want your browsing data collected. Using the data of children, whose judgement is still developing, to make more money is evil, in my view. So I state that clearly.
Big browser makers collect childrenās data too and use it for all kinds of commercial activity. Compared with them, I think I am giving up chances to earn more. Being a paid app also makes it relatively weak in store search rankings. Itās a hard trade-off, but I hold myself to a strict standard there.
Q. There is no way for a child to ask a parent for a new site from their own device.
Problems that can be solved by talking should be solved by parent and child talking directly. I donāt believe in doing everything through an app.
4.5 and 2.9
Q. The rating is 4.5 in Japan and 2.9 in the US.
I think tolerance for UI complexity differs by region.
Q. One review asked for instructions. In May 2026 you removed the help screen and rebuilt the start as a three-page onboarding.
I thought it was better to fix usability at the root than to add explanations.
Q. A browser is a product where the websites change on their own.
I handle what I can and leave what I canāt. To some extent, Iāve accepted that.
Q. Is there anything you wish you had built differently from the start?
I wish I had designed a parentsā area inside the app from the beginning, as it is now. On the other hand, since I made it as a DIY project, I kept releasing it as a simple, ultra-light app, and before I knew it the number of users had grown. I liked that easy-going way it happened.
Users and price
Q. Is there any feedback that stayed with you?
I get messages from all over the world saying itās simple but a very powerful tool, and that it helps.
Q. The suggested sites in onboarding differ by language.
I pick sites that are popular in each language area.
Q. How did you set the price at Ā„1,500 in Japan and $9.99 in the US?
StudyX uses a one-time $9.99 as the global baseline for its apps. If Iām lucky enough to have users who buy at that price, I can make a living and keep improving apps and building new ones. That is the line. Almost all my apps are made for the whole world, so many small things add up.
Q. A word for parents wondering whether to try Kinder Browser?
Itās quietly useful, so please give it a try. And if anything bothers you, send feedback any time. Iāll respond as quickly as I can.
About Kinder Browser
Browsing starts from the home page and bookmarks. Links within the same site open, and links to another site are stopped unless that site is bookmarked or on Whitelisted Pages. A built-in blocklist focused on adult and gambling sites is included. The parentsā screens are protected by a multiplication question or a custom PIN, and the app can be used alongside Screen Time.
For using it with Screen Time, see How to Set Up Screen Time on an iPad for Your Child. For a first session, see Getting Started with Kinder Browser. The app itself is described on the Kinder Browser page.
