We create game-changing apps  that transform your business from the inside out.

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React Atom

Instead of splitting development across multiple languages, platforms, and teams, React Universe combines front and back-end development with cross-platform capabilities using a single programming model.


We create game-changing apps that transform your business from the inside out.

Optimization of Products and Processes

Optimization of Products and Processes

Diagnose performance issues and develop solutions that establish new standards for your product and operations
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Special Services

Optimization of Products and Processes

Use super apps in your organization

Master of the react universe
Team Upskilling

Team Upskilling

Unlock the full potential of your in-house team - we can help your developers tackle the most complex challenges
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Special Services

Team Upskilling

Use super apps in your organization

Master of the react universe

Case studies


“The team at Callstack are the most experienced and trusted engineers in the React Native community and ecosystem.”

Nader Dabit
Senior Developer Advocate at Amazon Web Services

“Callstack made the perfect staff augmentation partner. Their engineers proved to be a crucial part of our mobile app relaunch project.”

Brian Aznar
Engineering Director of Major League Soccer

“I appreciate their attention to detail, flexible approach and a high degree of expertise. I definitely recommend the Callstack team!”

Glen Moriarty
Founder and CEO of 7 Cups

“The collaboration was great throughout, with Callstack engineers seamlessly working as part of our agile teams.”

Gareth Jenkins
Head of Engineering ‑ Trades Product

How we work

A holistic approach to software design:
Principle 1

People first

The people layer is as important as the code layer. People are at the center of innovation. The heart of software. The way we interact and communicate with each other shapes the things we make. So when you’re designing software, the best place to start is not your product, but your people.

Principle 2

Think Small

Small is beautiful. Small is agile, responsive and efficient. Small teams make better code. So when you're designing your software, choose modular, loosely linked, highly cohesive teams. They breed better products, build better organizations and you only need two pizzas to feed them, too.

Principle 3

Open over closed

Business is always better open than closed. Open source development helps organizations operate with agility by rapidly integrating new technologies into their stack. Teams can also easily connect open source software to other tools they use every day, while drawing top talent from the coding community.

Principle 4

Declarative over imperative

Declarative programming focuses on the desired end result, not how you get there. When the goal is determined automatically, how you get there can always be optimized. Creating a future-proof solution. Declarative programming also makes development faster, simpler to customize and easier to maintain, test and grow.

Principle 5

Optimizing for change

Software development is not about reaching an end point. The clue is in the name. It’s about constantly developing, changing, adapting. Building on what’s come before, and reacting to what’s coming. The success is in the agility of the software, not its completion.

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