React Native Brownfield
Incrementally move your iOS and Android apps to React Native without breaking
552 stars
The AI delivery loop
Work does not stop between steps.
In traditional delivery, work moves in phases. In AI-native delivery, it flows. Agents continue where others stop. Our setup keeps that work moving for longer before a human needs to step in.
The multiplier
The best engineers got exponentially better.
AI amplifies what's already there. Callstack engineers have spent a decade building the framework that agents now write for. That depth doesn't disappear, it multiplies.
The missing 30%
Every agent loop needs a human at the end.
Agents don't architect. They don't debug what they can't see. The missing 30% is where Callstack lives.
Callstack was founded for a specific kind of moment.
A technology starts to prove itself. The opportunity is clear.
But most companies still do not know how to use it well.
That was React Native in 2016.
The promise was clear: one team, one codebase, more platforms shipped from a single codebase. The challenge
was underneath. Architecture. Performance. Native modules. Upgrades.
That is why we built Callstack.
We wanted to help companies use React Native without having to figure out every hard part on their own.
Now the shift is happening again.
AI is changing how software gets built. We have moved past code completion into fully agentic systems.
More work now happens in parallel, across multiple sessions, and the patterns, standards, anti-patterns, and tools around it are changing fast.
Our role is to help teams adopt this new model without having to solve every hard problem on their own.
At Callstack, our universal goal is simple.
When the way software is built changes, we help companies adopt it.
We have done this before with React Native.
And we are here to do it again.
Founder + React Native Core Contributor
From strategy to infrastructure
Everything you need to ship at AI speed
You understand how we work. Now pick the lane.
Expert engineering
Build and scale React Native apps.
Agentic Delivery
Turn AI into better software delivery.
Why teams bet on Callstack
From billion-user apps to React Native core, this is why teams choose Callstack when they need to move fast and get it right.
React Foundation
Founding Member
300+ commits to React Native
100+
Enterprise projects delivered
Industry runs on our tooling
50M+
OSS downloads / month
3.7×
Lower task cost vs Opus 5.5
I recommend them as a trusted tech partner for running complex projects.
5x
Faster message
sending time
ISO 27001 certified
Clients
Trusted by enterprise teams at scale.
Teamworks needed Module Federation, we helped make it real
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We had been struggling with React Native application performance until we met Callstack.
The trainers are always very helpful and supportive. It really makes a difference!
Not only does Callstack have tremendously talented engineers, but I know they care about the success of the project as much as I do.
I appreciate their attention to detail, flexible approach and a high degree of expertise.
Their engineers proved to be a crucial part of our mobile app relaunch project.
I recommend them as a trusted tech partner for running complex projects.
The team at Callstack are the most experienced engineers in the React Native community.
If you're looking for skilled and trusted React Native developers, Callstack is definitely the way to go.
