Agentic Infrastructure

AI-Driven QA & Testing

AI-Driven QA & Testing

Keep QA ahead of agentic delivery.

AI-native teams need verification that keeps up with local and cloud agents. We provide an AI QA agent that checks work in real time on devices, locally and on pull requests, so regression checks, exploratory QA, and release validation become part of the delivery flow.

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AI-Driven QA & Testing

Why test with Callstack

Keep QA moving with delivery.

We wire AI QA into local workflows, pull requests, CI, and hosted or on-prem environments. Teams catch regressions, accessibility gaps, and release risks without slowing implementation down.

Run it locally or in the cloud.

The same QA product fits local workflows, CI, and hosted environments.

Debug issues with better instrumentation.

Access to the UI tree, native profilers, and visual diffs makes issues easier to investigate.

Get it into the stack faster.

Setup is lightweight and it works with any framework that runs on device.

Services

Validate every change before release.

Use Cases

AI-Native Test Automation

Run automated checks against code written by engineers and agents, so QA keeps pace with faster implementation.

Automated Accessibility Audits for EEA

Check interfaces for accessibility issues during delivery, helping teams catch compliance gaps before release.

Cross-Platform Code Verification

Validate behavior across platforms from one QA flow, so shared code does not hide platform-specific issues.

AI-Generated Code Validation

Review AI-written UI and logic before merge, so speed does not introduce regressions, edge-case failures, or bad implementation choices.

Release Validation

Run final checks on critical journeys, builds, and environments before rollout starts.

Real-Device Testing

Test on physical devices, where performance, gestures, and native integrations behave differently than in simulators.

Regression Prevention

Catch regressions in core flows with validation wired into pull requests, CI, and pre-release checks.

On-Prem & Cloud QA Execution

Run the same QA agent inside your own infrastructure or in hosted environments, depending on policy and scale.

AI-Driven QA & Testing

Put an AI QA agent in your flow.

Tell us where testing slows your team down today. We'll come back with a plan to wire the QA agent into your delivery flow and what to prove out first.

Add QA agent

Design → Build → Extend

Design QA that keeps delivery moving.

Design

We map the mobile delivery stack, controls, and cost. You get the plan before migration starts.

See hosted vs self-hosted economics
Find the gaps in the delivery stack
1 WEEK

Build

We deploy QA, CI/CD, OTA, and telemetry. The mobile delivery stack runs in your environment from day one.

QA agent, OTA, and CI/CD included
Telemetry and release signals included
2-4 WEEKS

Extend

Your team owns the stack long term. We stay on to extend it as delivery needs grow.

Extend the stack beyond the first rollout
Add new agents as needs change
AS NEEDED

Manifesto

When the way software is built changes, 
we help companies adopt it.

AI-native teams run on a system, not only on tools. Agents move the work forward. Experts make the calls that shape the outcome.

Learn Callstack Delivery Model

Case studies

What shipping at AI speed looks like

Case Study Cover
Architecture & Performance
AI-Assisted Migrations
AI-Driven QA & Testing

Migrating Questrade Edge Mobile to a Faster, More Scalable Architecture

33%

fewer re-renders across most features

Case Study Cover
Architecture & Performance
AI-Driven QA & Testing
Self-Hosted CI/CD Infrastructure

Enhancing Application's Performance for Expensify

5x

faster message sending time

10 years of React Native → Now in your AI stack

Put an AI QA agent in your flow.

Tell us where testing slows your team down today. We'll come back with a plan to wire the QA agent into your delivery flow and what to prove out first.

Add QA agent

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.

Rocket ascending into a blue night sky with digital binary code forming its smoke trail.

10 years in React Native. Now shaping agentic engineering.

For a decade, we have helped define how teams ship with React Native. Now we are helping shape how they work with agents.

Founded in 2016 ·Backed by Viking Global Investors

React Foundation members. Core Contributors.

We are founding members of React Foundation and Core Contributors to React Native. You get direct access to people close to the decisions shaping the frameworks you use.

Open source since 2016. Our code runs in your app.

We contribute to React Native and maintain libraries across its ecosystem. Our code runs in apps used by millions of people every day.

Open Source Projects

39M+

Downloads / month

67K+

GitHub stars

300+

React Native commits

100+ Enterprise clients with 7B+ users.

We work with teams shipping at real scale. You get a partner used to high-stakes products, not learning on your roadmap.

Agent Conf. The conference for the Agentic era.

The conference we built for the shift from writing code to orchestrating agents.

Agent Conf
Gradient background blending white, light blue, and purple shades with smooth transitions.Man wearing glasses and a Stanford sweatshirt speaking into a microphone during a presentation.

We are Codex Ambassadors.

We run meetups, workshops, and hands-on 
sessions that help teams learn Codex 
and apply it in real work.

Check Events
Rocket ascending into a blue night sky with digital binary code forming its smoke trail.

10 years in React Native. Now shaping agentic engineering.

For a decade, we have helped define how teams ship with React Native. Now we are helping shape how they work with agents.

Founded in 2016 ·Backed by Viking Global Investors

React Foundation members. Core Contributors.

We are founding members of React Foundation and Core Contributors to React Native. You get direct access to people close to the decisions shaping the frameworks you use.

Open source since 2016. Our code runs in your app.

We contribute to React Native and maintain libraries across its ecosystem. Our code runs in apps used by millions of people every day.

Open Source Projects

39M+

Downloads / month

67K+

GitHub stars

300+

React Native commits

100+ Enterprise clients with 7B+ users.

We work with teams shipping at real scale. You get a partner used to high-stakes products, not learning on your roadmap.

Agent Conf. The conference for the Agentic era.

The conference we built for the shift from writing code to orchestrating agents.

Agent Conf
Gradient background blending white, light blue, and purple shades with smooth transitions.Man wearing glasses and a Stanford sweatshirt speaking into a microphone during a presentation.

We are Codex Ambassadors.

We run meetups, workshops, and hands-on 
sessions that help teams learn Codex 
and apply it in real work.

Check Events

Open Source

Want to build it on your own?

We open-source the tools behind our delivery model.
Use them, fork them, or let us run them for you.

Check All Tools
Explore AI Infrastructure
Agent Device

CLI to control iOS and Android devices for AI agents

188238
downloads / month
React Native Testing Library

Simple and complete React Native testing utilities that encourage good testing practices

9460312
downloads / month
Reassure

Performance testing companion for React and React Native

1438
stars
React Native Harness

Harness brings Jest-style tests to real native environments so you can test TurboModules like you would test your React Native app: with JavaScript.

136602
downloads / month
Rozenite

Plug-and-play panels for React Native DevTools. Install, enable, and start debugging in minutes.

665223
downloads / month
Skill Gym

Prove your agent skills work before you ship them

1500
downloads / month
React Native Evals

A benchmark suite for evaluating how coding models solve real React Native tasks

91
stars

Insights

Worth your time, by engineers.

Explore Insights
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Jul 6
·
Article

Introducing Sniffler: Run only the E2E tests your changes can affect

Sniffler helps JavaScript and TypeScript teams run only the E2E tests affected by a change. It traces import and export relationships and reduces unnecessary CI work without asking teams to give up test coverage.
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Jun 26
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Article

How Expensify Uses Agent-Device for Mobile Bug Evidence and Profiling

This article shows how we use agent-device with the Expensify app across three everyday mobile workflows: verifying bug fixes with recorded before/after evidence, measuring Sentry performance spans, and profiling React renders.
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Jun 24
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Article

Writing Custom Renderers for React

React Test Renderer’s deprecation forced React Native Testing Library to find a long-term replacement. In this article, Maciej Jastrzębski explains what it took to build a new JavaScript-only test renderer for RNTL and uses that process to show how React renderers actually work. It’s a practical look at React elements, Fiber, host instances, HostConfig, and React Reconciler for anyone who wants a clearer mental model of how JSX becomes UI.
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Apr 17
·
Article

How Skillgym Helps You Verify Agent Skills Still Work After Every Change

Small edits to a SKILL.md can change agent behavior in ways that are hard to spot manually. This article shows how skillgym helps you test skills against real agent runners, validate the right behavior, and catch regressions before they reach production.
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Apr 14
·
Article

Agent React DevTools: Give AI Agents Access to React Internals

Agent React DevTools gives AI agents direct access to the React component tree, state, and performance data. Instead of relying only on UI snapshots, agents can now inspect what happens inside React and debug issues with proper context. This enables more reliable QA, better performance analysis, and deeper automation for React and React Native apps.
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Apr 3
·
Article

How We Optimized Agent Device for Mobile App Automation

AI agents are powerful tools for mobile automation, but running them can get expensive and slow if they consume too many tokens. In this post, we break down how we optimized Agent Device to cut LLM token usage in half and speed up execution by 33%.
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Feb 17
·
Article

Agent Device: iOS & Android Automation for AI Agents

This article introduces agent-device, a new CLI for automating mobile UI workflows with AI agents. It explains what the tool is, how it helps developers with token-efficient snapshots and repeatable interactions, and why Callstack is building it to bridge exploratory agent behavior with deterministic replay across iOS and Android.
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Oct 15
·
Article

Introducing React Native Harness: Fast, Real-Device Testing for Native Modules

Introducing React Native Harness: a new way to test native modules directly on real devices and emulators. It brings together the speed and simplicity of Jest with the realism of on-device execution, giving developers a powerful, CI-ready tool to validate native behavior with ease. Harness makes it simple to ensure your native code works exactly as intended across every platform.
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Oct 3
·
Article

From Unit to E2E: A Guide to Testing React Native TV in 2026

While many React Native testing tools like Jest and Appium are transferable to TV development, they lack built-in support for remote control interactions. For component tests, this means the standard library helpers are insufficient, requiring developers to build their own mocks that emit low-level hardware key events to simulate D-pad focus changes. For end-to-end tests, it requires distinct configurations and commands for native versus web-based TV platforms. This article explains how to create these custom JS test helpers from scratch and how to set up Appium to run automated E2E tests on emulators, real devices, and device farms.
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Feb 5
·
Article

Type-Checking React and Redux (+Thunk) with Flow - Part 1

Flow is a static type checker for JavaScript that can help catch errors in React code. This guide walks through practical examples of using Flow to type check React components, including stateless functions, class components, transferring props, and higher-order components.
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Apr 25
·
Article

Using AI to Write Tests for React Components

Writing tests for UI can be tedious, but it's critical for ensuring code quality. This guide explores how AI tools like GitHub Copilot and ChatGPT can help make the process more efficient by suggesting test code for React components.
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Oct 5
·
Article

Time to Detox

Detox is a new end-to-end testing library for React Native that allows you to simulate user interactions and make assertions on the app's interface. This guide walks through how to set up Detox with Jest and write your first tests to check for expected text and behavior.
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Jun 23
·
Article

Testing With React Native Accessibility Snapshot

Adding accessibility tests to your React Native app doesn't have to be a chore. This guide walks through setting up AccessibilitySnapshot, simplifying test creation, and automating the process with GitHub Actions.
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Nov 6
·
Article

Testing a React App With Cypress

Cypress is a new open-source testing tool that makes it fast and easy to write end-to-end tests for web apps. We walk through setting up Cypress to test core auth flows like login and logout in a real React app.
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May 3
·
Article

Testing Your React Native Apps

Snapshot testing can save you hours of headache when upgrading React Native apps. This step-by-step guide shows you how to set up snapshot tests for iOS, capture reference images, and validate UI changes at a glance.
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Oct 29
·
Article

Testing React Native Apps in the Cloud - Part 2

Tired of waiting for tests to run on your local machine? This guide walks through how to set up cloud testing for React Native apps using XCUITest and AppCenter. You'll learn how to create test suites, submit your app, and verify the results across multiple devices.
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Sep 29
·
Article

Testing React Native With the New Jest - Part II

Testing Redux reducers and actions in React Native doesn't have to be tedious. This guide shows how to use Jest snapshots to easily capture the expected output of your Redux code, simplifying the process of writing and maintaining tests.
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Sep 9
·
Article

Testing React Native With the New Jest - Part I

Writing tests for React Native apps doesn't have to be painful. We explore how Jest's new snapshot testing feature makes it easy to catch bugs and verify your UI stays consistent as you iterate, without tedious manual comparisons.
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Oct 22
·
Article

Testing React Native Apps In the Cloud - Part 1

Testing React Native apps on real devices can be challenging, especially for rare or older models. Cloud testing services like Microsoft's AppCenter allow you to easily run tests on hundreds of iOS and Android devices in parallel, without needing physical devices. This guide walks through how to set up a React Native project and configure AppCenter to run tests in the cloud using native frameworks like XCUITest.
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Jun 12
·
Article

Testing Expo Web3 Apps With Wagmi and Anvil

Writing tests for web3 apps in React Native doesn't have to be daunting. This guide walks through configuring your project with Anvil, Wagmi, Viem, and Web3Modal, and shares practical tips for testing wallet connections, transactions, and edge cases without sacrificing speed or reliability.
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May 12
·
Article

Run Tests for Key Pieces of Your App

Writing automated tests is key to shipping React Native apps with confidence. This guide shares practical tips for testing the most important parts of your app, from unit testing components to end-to-end flows, without getting bogged down trying to achieve 100% coverage.
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Aug 5
·
Article

React Native Testing Library With Redux

Testing Redux with React Native Testing Library doesn't have to be complex. This guide walks through how to set up a custom render function to test your connected components in a real Redux environment, without relying on implementation details.
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Jan 10
·
Article

React Native Testing Library Turns Into Testing Library

React Native Testing Library and Native Testing Library have officially merged into a single library under the Testing Library family. The new @testing-library/react-native package combines the best of both libraries while providing a smooth migration path for existing users.
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May 28
·
Article

React Native Testing Library 2.0 - What’s New?

React Native Testing Library 2.0 is out with new features to improve testing React Native components. It adds automatic cleanup, async act support, and scoped queries with the within operator. The release also removes some deprecated APIs and improves compatibility with community projects.
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Sep 12
·
Article

React Native Android Accessibility Tips

Writing accessible React Native apps for Android takes extra care. This guide shares practical tips to fix common issues like inline text links, icon sizes, text input placeholders, header titles, and WebView styling to ensure your app works well for all users.
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May 18
·
Article

React Native Accessibility: What, Why, and How?

Accessibility in mobile apps is about enabling equal access for people with disabilities. This guide shares practical tips for implementing accessibility in React Native, from design considerations like color contrast and font readability to testing with screen readers and other assistive tools.
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Feb 2
·
Article

Performance Regression Testing for React Native

As your React Native app grows, performance tends to degrade over time. This guide shows how to catch performance regressions early with Reassure, a new open-source tool for automating performance tests in CI/CD pipelines.
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Jul 30
·
Article

Merge of React Native Testing Libraries

The React Native community has been using two separate testing libraries with near-identical interfaces. After much discussion, the libraries are finally merging into a single official package: @testing-library/react-native. The merge brings together the best of both worlds while making the migration process as smooth as possible.
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Sep 12
·
Article

Introducing E2E Tests to React Native Core

React Native's core team recently introduced automated end-to-end (E2E) tests to improve the framework's reliability and catch regressions early. The effort was a collaboration between engineers from Callstack, Microsoft, and Meta, who worked together to research, propose, and implement a robust E2E testing setup using Appium, WebDriverIO, and Jest.
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Jul 8
·
Article

From Enzyme to React Native Testing Library: How I Changed My Way of Unit Testing

Writing unit tests for React components can be tricky, especially when checking implementation details instead of functionality. This article shows how to refactor tests using React Native Testing Library to make them more effective and focused on what users actually interact with.
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Sep 21
·
Article

Continuous App Performance Monitoring Made Simple With Reassure

Tired of performance regressions slowing down your React or React Native app? Reassure is an open source library that makes it easy to write performance tests, integrate them into your CI, and catch issues before they hit production.
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Mar 11
·
Article

Consistently Improve App Performance With DMAIC and Reassure

Keeping React Native apps performant as they grow can be challenging. This guide walks through using the DMAIC process to consistently identify and fix performance issues, and catch regressions early with automated testing tools like Reassure.
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Sep 27
·
Article

A Comprehensive Guide to Mock Service Worker (MSW)

Tired of flaky tests and complex mocking? Mock Service Worker (MSW) lets you intercept real network requests in your tests, making it easy to test components that rely on APIs. We share best practices and advanced techniques for using MSW effectively in larger projects.
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May 13
·
Podcast

How AI Is Changing React Native Development and Testing

Zack Ebenfeld joins React Universe On Air to talk about how AI is changing React Native workflows, testing, QA, and day-to-day engineering work.
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Jul 17
·
Podcast

What's New in Reassure 1.0

Find out how to monitor React and React Native performance better than ever before with Reassure's new features.
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Jul 28
·
Podcast

Reassure - Open Source Tool Measuring Performance Regression

Explore Reassure, an Open Source tool for measuring performance regression in React Native apps.
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Jun 22
·
Podcast

React Native News and App.js Conf

Join Michał Pierzchała and Abi Thiao as they discuss the most interesting talks at App.js Conf 2022 and other React and React Native news.
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Aug 11
·
Podcast

Look into the Future of React Native Testing Library

The first episode of React Universe On Air (formerly known as The React Native Show) provides insights into React Native Testing Library. Mike and his guest give a quick glimpse into the very concept of Testing Library and tell the story behind React Native Testing Library.
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Aug 23
·
Podcast

Introducing E2E Tests to React Native Core

This episode of the React Native Show dives into the recent introduction of End-to-End (E2E) testing in RNTester. Join us as we unpack the thought process, technical considerations, and practical implementation of this new approach to testing in React Native.
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July 21, 2026
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Webinar

Behavior Review for AI-Native Delivery

AI can increase code output faster than teams can verify the real app. See why behavior review matters before merge.
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June 12, 2026
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Event

Giving AI Agents Hands: Mobile Feedback Loops with Agent Device

Mike Grabowski will speak at React Summit 2026 about Agent Device, Callstack’s agent-native automation layer for giving AI coding agents a practical feedback loop across mobile, TV, and desktop apps.
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July 6, 2026
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Event

Mobile QA with Cloud Agents at AI Coding Summit London

Michał Pierzchała will speak at AI Coding Summit London 2026 about mobile QA agents for iOS and Android pull request workflows.
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June 3, 2026
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Event

Callstack x Expo AI Meetup

Join Callstack and Expo in San Francisco for practical talks on AI-native mobile development, Expo Agent, Cloud Agents and autonomous mobile QA.
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June 17, 2026
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Event

Automating Mobile QA with Cloud Agents

Michał Pierzchała will present Automating Mobile QA with Cloud Agents at Ship London on 17 June 2026.
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March 19, 2026
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Event

Agent Device, AI workflows, and mobile testing in practice

A discussion on Agent Device, AI-driven workflows, and testing mobile apps using simulators and accessibility data.
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December 9, 2025
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Event

Write Once, Test Everywhere: Cross-Platform Testing for React Native

Join Szymon Chmal at WarsawJS #133 to explore cross-platform testing in React Native with a new approach powered by React Native Harness.
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November 14, 2025
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Event

Testing Native Modules Reliably With JavaScript

Learn how React Native Harness bridges the gap between mocking and E2E testing: real device tests, full native access, Jest-style simplicity.
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October 16, 2025
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Event

React Native Harness, Next.js 16 Beta & Remix v3

This week’s Live Dev Session dives into React Native Harness with Szymon Chmal, explores the Next.js 16 Beta and Remix v3 “pre-drop,” and breaks down the biggest React and React Native updates from the community and React Alicante 2025.
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October 4, 2025
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Event

Write Once, Test Everywhere: Cross-Platform Testing for React Native

Cross-platform testing in React Native made simple: a lightweight architecture to run and extend tests on any JavaScript-powered platform.
February 24, 2023
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Event

Automated Performance Regression Testing With Reassure

Developers often fix performance issues in React apps, but this is unsustainable and prone to regressions. Reassure, a testing library, helps spot problems before production, enhancing automated testing suites.
April 1, 2025
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Event

How to Run E2E Tests on Every PR and Don’t Burn All Your CI Credits

End-to-end tests are notoriously slow and costly, especially in mobile development. This talk introduces new tools and techniques to make E2E testing fast and efficient, so you can run tests on every pull request without draining CI resources.