Published works.

by , product builder

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Willi Wu

The author · 2000 to now · Product builder · Copenhagen · San Francisco

I build products, and I have been building software since 2000.

I started out building web applications in Copenhagen. I designed enterprise software at IBM Denmark, and built an online bookshop in Ruby on Rails. Then the iPhone arrived.

In 2008 I founded icelantern and began making iOS apps: one for Podio, an augmented-reality app for Carlsberg, and iPad apps for the Danish railway. A year later I started Robocat, and the rest of this shelf follows from there.

Thermodo took me from Copenhagen to San Francisco in 2015, and I have been building in the Bay Area ever since.

Work experience

Studied

Talks and mentoring

On the side

Robocat

Volume 1 · Robocat · 2009–2016 · Founder and lead developer · Copenhagen

A Copenhagen studio that dreamed up and built its own apps. Two people became fourteen.

We dream up and build award-winning mobile apps. That was the line on the door, and for seven years it held: a small studio in Copenhagen making its own products.

Outside came first, in 2009. Thermo followed and passed twenty million users. Haze, Wordbase, 101 Airborne and a yearly festival guide for Roskilde came after, and then a thermometer you could hold.

The apps

In the press

Also from the studio

Outside

Volume 1 · Robocat · 2009 · Founder and lead developer, Robocat · Copenhagen

The weather, seen through a window.

Outside was Robocat’s first app. Instead of a table of numbers it showed a window, and through it the weather where you are.

Apple featured it, a late-night host joked about it on air, and it set the tone for everything the studio made afterwards.

In the press

Thermo

Volume 1 · Robocat · 2011 · Founder and lead developer, Robocat · Copenhagen

One big red thermometer, and the temperature where you stand.

Thermo launched free in early 2011 as a test of the free model: one thermometer, one number, and adverts to pay for it.

People kept asking why yesterday’s temperature looked wrong. It is the reading from exactly 24 hours ago, not yesterday’s average.

In the press

Roskilde

Volume 1 · Robocat · 2011–2013 · Founder and lead developer, Robocat · Copenhagen

The unofficial guide to Roskilde Festival.

The idea came out of a lunch-break pitch one week before the festival. There was no data feed, so we copied every artist and set time off the festival website by hand.

The festival counted a day from six in the morning to six the next, so a Friday 1 a.m. set was really on Saturday, and we shipped a fix. Our app pushed the festival to open its data to developers.

In the press

101 Airborne

Volume 1 · Robocat · 2012 · Founder and lead developer, Robocat · Copenhagen

A Vietnam-era helicopter game, made with BLINDesign.

Fly, shoot, dodge, bomb. 101 Airborne was Robocat’s arcade game, painted like a war-movie poster.

On iPhone 5 launch day I queued, did not get a phone, and handed out 101 Airborne stickers instead.

In the press

Haze

Volume 1 · Robocat · 2013 · Founder and lead developer, Robocat · Copenhagen

Beautiful, simple weather.

Haze cleared away the clutter of weather apps: one soft disc of colour, the number that matters, and gestures for everything else.

It was a collaboration between Robocat and Taptanium, and it arrived in February 2013.

In the press

Wordbase

Volume 1 · Robocat · 2013 · Founder and lead developer, Robocat · Copenhagen

A word game played for territory.

Two players, one grid of letters. Spell a path from your base to theirs and take the board: orange against blue.

Wordbase was built together with the largest magazine publisher in Scandinavia.

DR TV

Volume 1 · Robocat · 2015 · Founder and lead developer, Robocat · Copenhagen

The Apple TV app for DR, Denmark’s national broadcaster.

When Apple TV opened to apps in 2015, Robocat built DR’s: the national broadcaster’s programmes, on the big screen.

Thermodo

Volume 2 · 2013–2016 · Founder · Copenhagen and San Francisco

A tiny thermometer for your phone. Robocat’s first hardware product.

Thermo showed a big red thermometer on screen, and some people left one-star reviews because it did not measure anything. So we built one that did.

Thermodo plugs into the headphone jack and reads the temperature right where you are. It launched on Kickstarter in March 2013 as a Robocat product. In 2015 I spun it out as a company of its own and took it through the HAX accelerator in San Francisco.

In the press

Be My Eyes

Volume 3 · 2013–2016 · Lead developer and technical advisor · Copenhagen

The app that connects blind and low-vision people with sighted volunteers over live video.

Hans Jørgen Wiberg, who is visually impaired, had the idea: lend your eyes over a video call. Robocat helped turn it into an app.

A blind person points their phone at something. A volunteer somewhere in the world says what they see. It launched as a non-profit in January 2015 and has kept growing ever since.

In the press

Plume

Volume 4 · 2016–2019 · iOS lead · Palo Alto

Mesh WiFi that tunes itself, sold mostly through internet providers.

Plume put small pods in the wall sockets around a home and let the network tune itself.

I led the iOS app: setting up the pods, seeing what was online, and making an invisible thing feel simple.

Cocoon

Volume 5 · 2019–2020 · iOS lead, founding full-time developer · San Francisco

A dedicated space for the most important people in your life.

Cocoon was a private space for your closest people: family, and the friends who count as family, kept close wherever they are.

I joined as the founding full-time developer and led iOS. In 2021 the team joined Substack, and you can still see Cocoon in the way Substack’s chat looks.

In the press

Fable

Volume 6 · 2020–2024 · Lead software developer · San Francisco Bay Area

A social reading app for online book clubs.

Fable makes reading something you do together: clubs, shared highlights and conversation in the margins.

I led the iOS team on the social reading club part of the app, from before launch through four years of growth.

In the press

SuperMe

Volume 7 · 2025 to now · Member of technical staff · San Francisco Bay Area

Indexing what people know, so you can ask the people who have done the work.

SuperMe is on a mission to index collective human knowledge and build the most useful network on the planet.

I am the solo iOS engineer, and I also work across web and backend.

In the press