Profile Image


I’m a Freelance Software Developer based in Berlin, Germany. I am skilled at building mobile apps for Android, iOS, and Flutter. I am passionate about mobile development, programming languages and machine learning, and also about sharing knowledge and building communities.

My Expertise

I’ve been working professionally as a developer since 2006, when I got my first job as a Java developer. I did my first mobile app for iOS in 2011, then I switched to Android in 2012. Since then, I’ve been building native apps for Android, iOS, and learning about other multiplatform solutions like Flutter.

In the past, I have also worked with embedded systems in C, I’ve created games in C++, and management tools in C#. Check my projects here.

As a mobile developer, I’ve been creating apps and libraries for eight years and I am still enjoying it. I enjoy working with Kotlin and Swift.

My largest app is the app, built in Kotlin for Android, which I created from scratch for Good Hood GmbH.

As well, I’ve been experimenting with Flutter, a new framework to build high-performant hybrid applications that run both on Android and iOS.

In the latest years, I’ve also been learning Machine Learning and Neural Networks, with special focus on practical approaches for mobile devices.

And last but not least, I love teaching. I am a public speaker and also blog author. I have spoken at conferences worldwide and my articles have helped thousands of developers understand complex concepts.

I’m also author at Pluralsight, where I published my course Android Navigation Architecture Components: Getting Started.

I’d be more than happy to help your team improve with workshops and seminars.

My way of working

I believe that communication is the most important skill that developers should have and I reflect that in my way of building things: well documented code, easy to read and easy to maintain. I am always happy to answer questions and collaborate even remotely.

What my managers/clients say about me

“[…] strongly recommend him for his professionality, leadership, organization and communication skills, and his major expertise in Software Development”

Sven Tantau - CTO of Good Hood GmbH

“Even in complicated problems, he was always able to familiarize himself quickly. Mr. Beltran has always exceeded the agreed goals even under the most difficult conditions.” (translated from German)

Martin Tews - Managing Director of castLabs GmbH

Work with me!

Sounds good? Then let’s work together! Send me an email to Recruiters are also welcome to contact me.

Download my CV
Download my Portfolio

rss facebook twitter github youtube mail spotify instagram linkedin google google-plus pinterest medium vimeo stackoverflow reddit quora