Making an iOS app in a week

A candid look at trying to develop and publish the app Animal Peekaboo in a week, by Eat More Pixel's co-founders Zac Fitz-Walter and Jimmy Ti.

Jimmy and I have been designing and developing iOS apps for over 9 years! 😲

However, we have very few of our own apps to show on the App Store.

Why? Because we mostly make apps for other people - individuals, researchers and companies. This means that often our work is hidden. If you were to search for Eat More Pixels on the App Store you won't find much.

So we decided to fix that by making more of our own apps.

But making apps takes a while right?

Wrong! Not if we made sure the app we were going to build was super simple.

So I proposed to Jimmy we give ourselves a week to build an app.

Jimmy's response? Challenge accepted. 😎

App in a week!

So how do you make an app in a week?

Easy, you cheat

I already had an app in mind before we started.

You see, I played the game Progress to 100 last year, a really clever puzzle game, which had one puzzle where you need to flip your phone face down and then tilt it up to hear a lion roar.

I really like the way they used the gyroscope to create that effect and I thought this could be adapted to create a playful and physical toy app for kids. One that could help teach them about the diversity of different animals and sounds.

I created some mockups and a coded a really simple prototype of the app in December last year.


When I say simple, I mean really simple. It was about 20 lines of code and a had a few images of cats.

It was enough to playtest it though with my partner's little relatives. 👶

Apart from getting a little drool on the iPhone screen, they responded really well to it. 👍

So technically before we started our development week we had the following:

  • Mockups to help explain the idea to Jimmy 🤔
  • A really basic prototype tested with little humans 👶

The Ninety-Ninety Rule

So we grabbed our laptops and began our development week. I would finalise the design and gather all the assets needed. Jimmy would code.

On Thursday 8th at 10am Jimmy created a blank Xcode project and we began.


However, going from a simple prototype to a fully complete app ready for the App Store is no easy feat. 

The Ninety-Ninety Rule is a very relevant rule to share at this point. It states...

The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time
— Tom Cargill, Bell Labs

And it's true.

So much of development time goes into polishing the app to make sure it's ready for humans to use.

This includes:

  • Making sure the design looks good on all the different device screen sizes
  • Sourcing and editing appropriate assets
  • Testing for usability issues and technical bugs

So we had a pretty intense week of development (especially as we were doing this part-time while working on client apps too).

Nonetheless, one week later we found ourselves submitting the app to Apple for review.

We did it!

Rejected! 😱

We didn't do it. 

A day after we submitted the app we received an email from Apple.

Our app had been rejected from the App Store. 


But it's okay.

This happens more often than you think and it's generally something you should plan for whenever you make an app. 

In our case it was because we had made our app an App for Kids and we didn't have a parental gate when accessing our settings. As this was our first App for Kids this was something we hadn't run into before.

Apple's response was clear and informative, and they provided a link that detailed what we needed to do to add a parental gate.

However, we had to implement it ourselves. 

So this meant further research and development time was needed.

We submitted an update 3 days later.


This time the Apple review took 3 days but it was approved this time.

Two weeks later our app is now available on the App Store!


Here's a few lessons we learnt:

  • Prototypes are important to test your idea
  • Polish takes a lot of development time
  • Your app may be rejected, prepare for this

Also a disclaimer, we want to make sure that we're not underselling our work and other developers. Not every app will take a week to build. Larger apps can take many weeks or months.

It might be surprising but if you wanted an app like this developed it could easily cost anywhere between $5-10k. It sounds expensive, but if we take into account the design, prototyping, development and testing then it adds up. If you want a rough estimate of the cost of an app then check out this website.

Next steps?

So where to from here? Well, the journey has only just begun.

The saying "If You Build It, They Will Come" is far from true on the App Store. 

So our next step is to look at how we can improve sales through marketing and also keep improving on the app through feedback.

We'll post a future update on how that goes.

Until then you can find our app on the App Store and find more information about it on our official Animal Peekaboo app page

Full disclaimer: No animals were harmed in the process of making this app. Just a lot of colleagues were annoyed by the many animal sounds coming from our office.

Zac Fitz-Walter