development experts

We support and inspire other developers and companies to launch their products for everyone at the same time, on every platform

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React native

Cross-platform development, workshops, and consulting


Master cross-platform development quickly



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Hire the best developers and deliver great products

Behind callstack

Mike Grabowski

In cross-platform development we trust! As co-creators of React Native, two years ago we dove into the new wave of software development with open minds and hearts, evangelizing and teaching how to write once and run everywhere.

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Anna Lankauf

We are well-known in the community, contributing to many Open Source projects, and organizing the first European React Native conference, React Native EU.

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Mike Grabowski

Mike Grabowski

Co-Founder & CTO

Anna Lankauf

Anna Lankauf

Co-Founder & CEO

Meet the team
Mike Grabowski Mike's signature
Anna Lankauf Anna's signature


of your most beloved apps
are cross-platform and use Open Source libraries


We contribute to the Open Source community by making our own Open Source software

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How we work

Your direction
Our code

Callstack’s goal is to help you and your team deliver a great product. That’s why working with us feels significantly different to what you might have experienced with external teams. We feel like your developers, just working remotely today.

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We make sure that your app is not only cutting-edge, but rock solid in the long term.

Always in Touch

We're happy to use any software you prefer, be it Slack, Asana, Trello, etc.

Pay as You Go

We are your own full-time employees, but with a short-term commitment.

What our clients say
    Working with Callstack has helped us complete several large projects and raise the developer IQ!
    Todd Williams
    Not only does Callstack have tremendously talented engineers, but I know they care about the success of the project as much as I do. Having a true partner is a wonderful experience and gives us the ability to move so much faster than we could without them.
    TC Davis
    We at We Are Voice realized the need to have a React Native app for our choral music service. In that process, Callstack became a natural development partner for us given their deep knowledge of the platform. Despite the geographical distance, our collaboration has been successful with strong deliveries on time, together with a good communication.
    Martin Rolinski, CEO
    We Are Voice
    We worked together for over 9 months to deliver a game-changing educational platform with some forward-thinking design elements (...) I would have no hesitation in recommending Callstack to others, to provide a flexible solution to an existing workforce or on a longer-term basis as part of a remote team.
    Ben Caulfield, CEO & Co-Founder
    Callstack team cares deeply about not just the project but also the people they partner with. It’s not often that you see this in a Sam with Deep domain expertise and relentless energy.
    Raghav Kapoor, CEO
    We worked with Callstack on our React Native app. Being half way around the world, they were very communicative and followed our technical instructions carefully.
    Adeel Raza
    San Francisco Wrocław


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