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Hydration failed because the initial ui does not match what was rendered on the server. Don’t you just love hate it when that happens?

In this guide, you’ll gather how to identify and solve the most common bugs and performance issues. We’ll cover debugging client-side React, if you have a React app that uses server-side rendering, you can also look at our Node.js debugging guide or on-demand workshop. In the below sections you’ll learn.

OpenTelemetry can be used to trace React applications for performance issues and bugs. You can trace user requests from your frontend web application to your downstream services. OpenTelemetry is an open-source project under the Cloud Native Computing Foundation (CNCF) that aims to standardize the generation and collection of telemetry data. Using OpenTelemetry Web libraries, you can instrument your React apps to generate tracing data.

Fetch Waterfalls are scenarios where multiple fetch requests are invoked in a sequential manner, not in parallel. This leads to some serious performance degradation. Here’s how they look: In this case, the second and third requests can be fetched in parallel, which will improve the page load and data display by 4.053 seconds. The negative performance impact with fetch waterfalls is also stacking - meaning the more requests there are, the worse the performance impact is going to be.

React is an open source JavaScript library known for its simplicity and incredible performance when creating an interactive user interface. React has gained wide adoption from web developers and reputable companies. While there are other frameworks in the JavaScript ecosystem, React is often the first choice when it comes to user interface and frontend business logic.

In this article, we’re going to look deeply at React Server Components (RSCs). They are the latest innovation in React’s ecosystem, leveraging both server-side and client-side rendering as well as streaming HTML to deliver content as fast as possible. We will get really nerdy to get a full understanding of how RFCs fit into the React picture, the level of control they offer over the rendering lifecycle of components, and what page loads look like with RFCs in place.

Have you seen this problem? Or maybe this one? You’ve most likely seen this: Hint: they’re all the same. The first image is Sentry’s Event Details page, the second is Chrome’s Network tab, and the code snippet is what causes it. If you can answer yes to any of these, then you need to keep reading. If not, you still need to keep reading, so your future self can thank you. This is called “fetch waterfall” and it’s a common data fetching issue in React.