App development - Cobalt Sign Symbol

The Chemistry of Apps

We like to take a meticulous approach to creating gorgeous apps,

starting from just an idea to product launch.

#iOS   #Android   #Windows

App development - Cobalt-Sign-Office-Desk
App development - Mobile-Summer-App-Course
App development - Cobalt-Sign-React-Native-Redux-Development
Our Style

Engineering & Passion

It is all chemistry. We enjoy building mobile apps, our languages of choice are: Swift, Java, React Native.

Our proven chemical formula for the best product = passion + attention to details + UX + tech skills + reliable team + good communication

Our Values

Teamwork & Good Times

We care a lot about team spirit and enjoying time at the office.

Also, we like to share and contribute to our community by organising free summer courses for students & creating pro-bono apps for local NGOs.

App development - Mobile Summer 4.0 City Apps
App development - Cobalt-Sign-2017-Christmas-Office -Cobalt
App development - Cobalt-Sign-Teambuilding-Berlin

Our own app,
"Ready Set Holiday!", has
1.5 million downloads and a
4.5 rating on the stores.

We love it →



International Awards

We always love a good challenge, enjoy taking part in competitions and, of course, receiving awards.

Samsung Gear App Challenge

We created a wearable version of our Tea Cup app designed for Samsung Gear 2. It was one of the winners in Round 1 of the Challenge.

Nokia Developer Champion

Awarded to Oana Csertus in May 2013. “Nokia Developer Champion is a recognition and reward program for top mobile developers from around the world.”

Fast Track to the Mobile App

Design & development competition by Core77 and Microsoft in November 2011. Our app, 1tap2send was one of the notable finalists.

Imagine Cup “Rockstar”

“Windows Phone Rockstar Award” 2010. We reached the top 10 with our app, Hawkeye, a travel trails app, that organised your photos and created a map trail.

Apps DD loyalty business app


October 15, 2016

Apps - ibrand

Project iBrand

March 30, 2016

cooking app

PetitChef for Android

March 24, 2015

Apps - Vocea Romaniei Windows Phone

Vocea României 2013

December 1, 2013


“Brilliant and intelligent team, precise, professional and extremely on-time, transparent and very friendly. Was a very pleasing and professional collaboration.”

Reza Paya, CTO ARMNet

“We love working together with Oana and Arthur from Cobalt Sign. They are highly skilled experts for mobile platforms and combine great UX design and coding skills.”

Simon Schweigruber, CEO - Dream Production AG

“Cobalt Sign delivered professional results within a very short time, which helped us meet the deadline for a product-launch. In addition to the professional results of the accomplished work, we especially want to highlight the quick understanding of our requirements and the structured, professional way of working.”

Mark Voorboom, Product Manager - Stb Automatisering & Advies BV

“I've had the pleasure of working with the Cobalt Sign team on a few projects and I'm looking forward to working with them again. Using a clean and structured project management approach, oriented to getting things done, they were able to deliver high quality work on amazingly short deadlines, while leaving out the stress and chaos that usually arises in these situations. Did I mention they consistently create beautiful and responsive UI's?”

Andrei Marinescu, CTO - Appscend

We can help bring your mobile app ideas to life.

Let's talk