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Sherlo VS React Engine

Compare Sherlo VS React Engine and see what are their differences

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Contents:
  1. ยป Base Details
  2. ยป Videos
  3. ยป Reviews
  4. ยป Alternatives

Sherlo logo Sherlo

Visual regression testing for React Native. Compare screenshots on iOS & Android simulators, catch visual regressions before release. Free plan, no credit card.

React Engine logo React Engine

A react render engine for Universal (previously Isomorphic) JavaScript apps written with express, by PayPal
  • Sherlo Baseline vs snapshot, side by side
    Baseline vs snapshot, side by side //
    2026-08-05
  • Sherlo Changed pixels highlighted automatically
    Changed pixels highlighted automatically //
    2026-08-05
  • Sherlo Review as a team - report and comment
    Review as a team - report and comment //
    2026-08-05
  • Sherlo Built-in inspector - the code behind any screen
    Built-in inspector - the code behind any screen //
    2026-08-05
  • Sherlo Compare against your Figma design
    Compare against your Figma design //
    2026-08-05

Sherlo is a visual regression testing tool built specifically for React Native. On every build it renders your app on real iOS and Android simulators in the cloud - native rendering, not React Native Web - screenshots every screen, and compares each against the previous version pixel by pixel.

When something changes, the whole team - developers, designers, PMs, and QA - reviews the diffs together in a shared web app and approves or rejects them before release. It catches unintended visual regressions and confirms intended UI changes look exactly as designed, across many devices, screen sizes, themes, and languages.

Sherlo plugs into any CI pipeline and integrates with Storybook, turning your existing stories into an automated visual test suite. The cloud simulators are included from the free plan - no device farm to build, no credit card to start.

Unlike Percy, Applitools, and Chromatic (web-first, multi-platform generalists), Sherlo is the React Native specialist: it tests how your app actually renders on device. Used in production by React Native teams, from fintech to social apps.

  • React Engine Landing page
    Landing page //
    2023-10-02

Sherlo

Website
sherlo.io
Pricing URL
Official Sherlo Pricing
$ Details
freemium
Platforms
SaaS Web Cloud CLI
Release Date
2022 January
Startup details
Country
Poland
City
Szczecin
Founder(s)
Dawid Krajewski, Michaล‚ Ziรณล‚kowski
Employees
1 - 9
Edit details

React Engine

Website
github.com
Pricing URL
-
$ Details
-
Platforms
-
Release Date
-
Edit details

Sherlo features and specs

  • iOS & Android simulators
    Renders your app on real iOS and Android simulators in the cloud - no device farm to manage.
  • Pixel-by-pixel diffs
    Screenshots every screen and compares each against the previous version, flagging changed pixels.
  • Team review app
    Developers, designers, PMs and QA review changes together and approve or reject before release.
  • Storybook integration
    Turns your existing Storybook stories into an automated visual test suite.
  • CI integration
    Runs in CI on every build via the CLI; both platforms in one run.
  • Device/theme/language matrix
    Test across many devices, screen sizes, themes and languages from one config.

React Engine features and specs

  • Isomorphic rendering
    React Engine enables both server-side and client-side rendering of React components, providing a seamless isomorphic/universal JavaScript experience. This allows for faster initial page loads and better SEO while maintaining rich client-side interactivity.
  • Express.js integration
    React Engine is designed as a view engine for Express.js, making it easy to integrate React into existing Express-based applications with minimal configuration. It follows familiar Express conventions for setting up view engines.
  • Built-in React Router support
    The library comes with built-in support for React Router, enabling developers to easily set up server-side and client-side routing without complex manual configuration.
  • PayPal backing
    React Engine was developed and maintained by PayPal, which provided credibility and ensured it was battle-tested in a large-scale production environment before being open-sourced.
  • Simplified setup
    The library abstracts away much of the complexity involved in setting up server-side rendering with React, reducing boilerplate code and allowing developers to get a universal React application running quickly.

Possible disadvantages of React Engine

  • Abandoned project
    The repository appears to be no longer actively maintained, with no recent commits or updates. This makes it risky to use in production as bugs and security vulnerabilities may go unpatched.
  • Outdated dependencies
    React Engine was built for older versions of React and React Router. It may not be compatible with modern versions of React (16+, 17, 18) or React Router (v5, v6), limiting its usefulness in current projects.
  • Limited ecosystem support
    The library is tightly coupled to Express.js, meaning it cannot be easily used with other Node.js frameworks like Koa, Hapi, or Fastify, reducing its flexibility.
  • Better modern alternatives
    Modern tools like Next.js, Remix, and Vite with SSR plugins provide far more comprehensive and well-maintained solutions for server-side rendering with React, making React Engine largely obsolete.
  • Limited documentation and community
    The project has relatively sparse documentation and a small community, making it difficult for new developers to troubleshoot issues or find examples and best practices for advanced use cases.

Analysis of React Engine

Overall verdict

  • Unable to verify a project specifically named 'React Engine' on GitHub with confidence, as this does not correspond to a widely recognized or well-documented open-source project that I have reliable information about. There may be multiple small or niche repositories using this name, and quality would vary significantly between them.

Why this product is good

  • React Engine is not a commonly recognized name in the mainstream React ecosystem
  • No verifiable consensus data on stars, maintenance status, documentation quality, or community adoption is available
  • Could refer to a personal project, a boilerplate, a rendering engine, or a niche tool - without more context, its quality cannot be assessed
  • Names like this are sometimes used for student projects, abandoned repos, or experimental tools that lack production readiness

Recommended for

  • Not recommended without further verification
  • Developers should search GitHub directly, check star count, last commit date, open issues, and documentation before adopting
  • Best suited for evaluation on a case-by-case basis rather than a blanket recommendation
  • If you have a specific repository URL, sharing it would allow for a more accurate assessment

Sherlo videos

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Visual testing for React Native ยท Sherlo demo

React Engine videos

No React Engine videos yet. You could help us improve this page by suggesting one.

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Category Popularity

0-100% (relative to Sherlo and React Engine)

Sherlo

React Engine

Software Development
100 100%
Software Development
0% 0
eCommerce Tools
0 0%
eCommerce Tools
100% 100
Automated Testing
100 100%
Automated Testing
0% 0
Customer Experience Management
0 0%
Customer Experience Management
100% 100

Questions & Answers

As answered by people managing Sherlo and React Engine.

What makes your product unique?

Sherlo's answer

Sherlo is the visual regression testing tool built specifically for React Native. It renders your app on real iOS and Android simulators in the cloud - native rendering, not React Native Web - and diffs every screen pixel by pixel. Web-first tools like Percy, Chromatic, and Applitools can't test how a React Native app actually looks on a device; Sherlo does.

Why should a person choose your product over its competitors?

Sherlo's answer

Because it's the React Native specialist. Percy, Applitools, and Chromatic are multi-platform generalists that test web-framework Storybook in a browser, not native iOS/Android rendering. Sherlo runs your app on real iOS and Android simulators, covers both platforms in one run, plugs into CI, and includes the cloud simulators from a free plan - no device farm, no credit card.

How would you describe the primary audience of your product?

Sherlo's answer

React Native teams that ship UI frequently - developers, designers, PMs, and QA who want to catch visual regressions before release. It fits teams already using Storybook and anyone shipping to many devices, themes, and languages who can't check them all by hand.

What's the story behind your product?

Sherlo's answer

Sherlo was built by React Native developers who kept shipping UI bugs that slipped past functional tests and were painful to catch by hand across devices. Existing tools were web-first and didn't test native mobile rendering - so they built the visual testing tool they wanted for React Native.

Which are the primary technologies used for building your product?

Sherlo's answer

React Native, TypeScript, an open-source SDK/CLI (github.com/sherlo-io/sherlo), cloud-hosted iOS and Android simulators, and a web app for reviewing diffs. Integrates with Storybook and any CI pipeline.

User comments

Share your experience with using Sherlo and React Engine. For example, how are they different and which one is better?
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Social recommendations and mentions

Based on our record, React Engine seems to be more popular. It has been mentiond 1 time since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

Sherlo mentions (0)

We have not tracked any mentions of Sherlo yet. Tracking of Sherlo recommendations started around Aug 2026.

React Engine mentions (1)

  • react-engine vs other template engines
    I was wondering to use paypal's React Engine (https://github.com/paypal/react-engine), but I have some doubts:. Source: over 4 years ago

What are some alternatives?

When comparing Sherlo and React Engine, you can also consider the following products

Applitools Eyes - Automated visual application testing and monitoring

Imagium.io - Accelerate your software testing process with one of the most advanced visual comparison tool from the future

Lost Pixel Platform - Visual Regression Testing for busy engineers

PixellPeep - Visual regression testing with 6 comparison algorithms, bulk CSV comparison, and native Playwright/Cypress/Puppeteer SDKs. AI diff explanations. Free tier.

Spectre - Spectre is a web application to diff screenshots.

VisualReview - VisualReview, a human-friendly tool for testing and reviewing visual regressions.

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