Web Performance – Renderland’s Saga, Book 1

“Data is like cash: to be of worth it should flow into, and in circulating it will possibly enhance in amount and, hopefully, in worth.” ~ Louis L’Amour

In February, I had a job to enhance the efficiency of an NFT market. I had floor data of internet efficiency on the time. I spent an insane period of time researching and watching tech talks on movies. I made a decision to write down this text to make the journey simpler for you.

The Portal 👨🏿💻

Aimlessly in search of solutions with a gazillion tabs open, my PC freezes with no resolution in sight. I resolve to close down my PC after which exit for a stroll to clear my ideas.

I return half-hour later to discover a unusual blue gentle emitting from my room. It was coming from my PC which was nonetheless on however frozen. I attempt lengthy urgent the facility button however I find yourself getting sucked into the display screen.

The Large Robotic 🤖

I get up in a weird-looking room then I instantly get approached by an enormous robotic with the letters HTML on its chest.

🤖 Robotic: Hello, I am HTML5. I am glad you awakened, welcome to Renderland!

👦🏿 Me: The place am I?

🤖 Robotic: You are in Renderland.

👦🏿 Me: Render what???

What’s Renderland? 🤔

Renderland is the planet on which Rendering takes place. It is the closest planet to the display screen and it is what customers see and work together with. It is positioned within the Browser's Photo voltaic System which can be underneath the The Net Galaxy.

This diagram reveals how a typical request travels via the web the place it lastly reaches a server which sends again a response to the consumer.

The response manifests totally different entities corresponding to Kinds, Markup, Scripts, Fonts, and different recordsdata. They signify the totally different life types on Renderland. They reside collectively to make up the content material that you simply see and work together with.

The Residents of Renderland 🪐

HTML, the planet’s elder summoned us all for a gathering underneath the Sacred Tree.

🤖 Robotic 1 I am HTML, you have most likely met my grandson, HTLM5. We’re each from the Markup tribe and we make up the content material of pages on the net.

🤖 Robotic 2 I am CSS from the Kinds tribe, and we give internet pages seems and type.

🤖 Robotic 3 I am JavaScript however you possibly can name me JS, I am from the Scripts tribe- no relation, and we observe making internet pages interactive.

🤖 HTML A prophecy spoke of a FullSnack Engineer with a mechanical keyboard and an E mark who’d save Renderland. The Engineer spoke an historic language referred to as Code.

🤖 JS We consider you are the chosen one.

Renderland’s Historical past 🕰

Way back, the robots lived in a faraway land referred to as ServerLand the place they served a bunch of entities referred to as shoppers. The shoppers lived in ClientLand they usually all had totally different styles and sizes.

A Serverland native is known as server and a Clientland native is known as consumer.

The request-response-cycle is a mannequin that describes how shoppers and servers talk over a community by way of a protocol corresponding to HTTP or Net Sockets.


Rendering is the method of turning an online web page’s belongings (HTML, CSS, JSS, and different static belongings) into interactive content material on the browser. Rendering steps embrace type, structure, paint, and, in some instances, compositing.

Essential Rendering Path (CRP) 🛣

The Essential Rendering Path is the sequence of steps the browser goes via to transform the HTML, CSS, and JavaScript into really seen pixels on the display screen.


The Render Tree 🌲

HTML5 and CSS then summoned me to the Sacred Tree. They started explaining the historical past of the tree and the way it got here to life.

  • Doc Object Mannequin (DOM) describes the construction browsers use to signify HTML components internally.

  • CSS Object Mannequin (CSSOM) describes the construction browsers use to signify CSS types internally.

Each are represented internally as a tree-like construction that permits applications to work together with the CSS and HTML content material of an online web page.

The Render Tree is the product of mixing DOM and CSSOM timber. It defines the construction of an online web page. The tree accommodates solely the seen components of an online web page.

The browser calculates the structure of every seen component after which paints it on the display screen with the assistance of the Render Tree.

Untitled Diagram.drawio (5).png

Format (Reflow) 🗺

Browser computes the geometry of the structure and its components primarily based on the render tree.

Paint 🎨

Browser paints pixel by pixel to create the visible illustration we see on the display screen. Utilizing the Render Tree, the browser engine calculates the place of every seen component of an online web page.

Rendering in Quick

  • Belongings Changing the net web page’s HTML and CSS code into DOM and CSSOM.
  • Render Tree Establishing the Render Tree by combining DOM and CSSOM.
  • Format Calculate the scale and place of every node.
  • Paint portray components on the browser’s display screen for customers to view.

Rendering Patterns

The robots then started explaining how rendering is practiced in Renderland.

Server Aspect Rendering (SSR) 🛠

Essentially the most historic type of Rendering. This sample generates the complete HTML for the web page content material to be rendered in response to a consumer request.

Consumer Aspect Rendering (CSR) 💻

This type of rendering turned widespread in the course of the Ajax period in 2005. Ajax which stands for Asynchronous JavaScript and XML allowed builders to construct client-side functions.

On this sample, the server renders a skeleton of an HTML container while the consumer handles the logic required to render an online web page. The consumer takes care of fetching, templating, routing, and many others.

Guardians of Renderland (The Pillars 👺)

Often known as the Net's Vitals, they’re Renderland’s guardians of efficiency. They measure and report any points which will have an effect on the efficiency of an online web page.

Screen Shot 2022-05-14 at 01.37.03.png

This screenshot is from Lighthouse's report on Hashnode’s dwelling web page.

First Pillar (First Byte) 1

This Pillar is chargeable for reporting the arrival of the very first byte of incoming information. It helps amount a server’s response time by measuring the latency of a spherical journey to and from stated server. It precedes each different Pillar.

Time to First Byte (TTFB) The time between the preliminary request and the arrival of the primary byte.

Second Pillar (Paint) 🎨

This Pillar measures the time a browser takes to color pixels on a display screen. The shorter the time, the higher the efficiency.

First Paint (FP)

The primary occasion of content material that seems on the browser. Consider it as the primary drop of water once you open the faucet.

First Contentful Paint (FCP)

Measures how lengthy it takes the browser to render the primary piece of DOM content material after a consumer navigates to your web page.

💡 The really helpful FCP rating is 1.8 seconds or much less

Largest Contentful Paint (LCP)

The time when the primary web page content material turns into seen. It consists of the preliminary HTML doc + LCP Useful resource.

💡 The really helpful LCP rating is 2.5 seconds or much less

Third Pillar (Time to Interactive) 🎬

Often known as (TTI), represents the state at which an online web page is prepared to answer occasions and consumer interactions. That is made doable when all of the Scripts tribe members have arrived/loaded.

TTI is reached solely after FCP. Having an enormous hole between these two metrics causes critical issues.

💡 The really helpful TTI rating is 3.8 seconds or much less

Whole Blocking Time (TBT)

The overall period of time between FCP and TTI. It implies that the occasion handlers are registered for many seen web page components, and the web page responds to consumer interactions inside 50 milliseconds.

💡 The really helpful TBT rating is 200 milliseconds or much less

Assault on Renderland 👾 – Second Act

“If you recognize the enemy and know your self, you needn’t concern the results of 100 battles. If you recognize your self however not the enemy, for each victory gained additionally, you will undergo a defeat. If you recognize neither the enemy nor your self, you’ll succumb in each battle.” – Solar Tzu, The Artwork of Battle.

We obtain a number of reviews from totally different places. Net pages are unresponsive, some fail to load and others are painfully sluggish.

It was later revealed that Renderland is being invaded by an clever species of bugs. They got here in numerous styles and sizes and wreaked havoc on the planet.

Bugs 👾 vs Pillars 👺

The bugs have directed their first assault on the pillars. Let’s examine how every metric impacts efficiency.

First Pillar (First Byte) 1

The bugs that have an effect on this community often manifest within the type of community or gadget points.

The next elements might have an effect on TTFB

  • The Community protocol, HTTP/1 as a substitute of HTTP/2 for instance.
  • Longer community request phases. You possibly can be taught extra about this here.

Second Pillar (Paint) 🎨

This metric primarily reviews efficiency points associated to static/viewable content material. The bugs that have an effect on this metric often manifest within the type of unoptimized belongings corresponding to HTML, CSS, and pictures.

Third Pillar (Interactivity) 🎬

The bugs that have an effect on this pillar primarily deal with scripts because it focuses on points associated to the interactivity/usability of an online web page. Unoptimized JavaScript is the largest offender on this class as a result of it must be parsed and compiled earlier than it is lastly executed.

Miscellaneous Efficiency Bottlenecks

These are a few of the most typical internet efficiency bottlenecks.

Blocking Assets

These embrace the scripts, types, and HTML imports that block or delay the browser from rendering content material to the display screen.

Bundle Dimension

That is the quantity of JavaScript a consumer should obtain to load your web site. A bigger bundle dimension means customers should wait longer earlier than they may work together along with your website.

Community Requests

Huge community payloads scale back the appliance’s efficiency. Additionally, larger latencies make requests take longer to journey to and from the server.

DOM/CSSOM Bottlenecks

  • Occasion handlers are expensive.
  • Format thrashing and reflows trigger re-renders which means the browser should recalculate and re-paint content material with each reflow.

The Resistance – Last Act

“With nice energy comes nice accountability.”

As builders, we should be sure that the apps we construct are performant and resilient. This part will equip you with new superpowers to imagine this position.

Measuring Efficiency

To defeat the bugs, we want absolutely perceive to tips on how to measure the influence of their assaults on efficiency.

💡 How is efficiency measured?

  • Subject Testing Includes actual customers loading and interacting with the web page.
  • Lab Testing Utilizing instruments to simulate a web page load in a predictable setting.

Subject Testing

Often known as Actual consumer monitoring (RUM) refers back to the technique of recording consumer interactions on a manufacturing web site.

Examples of RUM software program: InfluxDB, Google Analytics, CloudFlare, Stackify, and many others.

This subject is past the scope of this text so we’ll leap proper into Lab Testing.

Lab Testing

Refers back to the technique of testing an software in an setting corresponding to growth or staging earlier than the location is launched to the general public.

Rescuing the Pillars

Studying tips on how to measure the efficiency of an internet site was step one. Now we have to learn to optimize the metrics we measured.

First Pillar (First Byte) 1

This metric signifies how briskly or sluggish a server is. It measures the latency of a spherical journey to and from a server.

💡 Measuring TTFB

How you can enhance TTFB

  • Higher server infrastructure (Utilizing Load Balancers and Caches) for instance.
  • Pre-connect to required origins for cross-origin assets.
  • Utilizing HTTP2 if doable.

Second Pillar (Paint) 🎨

Asset optimization can play an enormous position in enhancing this efficiency metric. Let’s examine how we will accomplish this.

💡 Measuring Paint Metrics

How you can improveFCP

  • Remove render-blocking assets.
  • Minify CSS and take away unused JavaScript code.
  • Cut back TTFB.
  • Keep away from monumental community masses and pre-load essential requests.
  • Serve static belongings with an environment friendly cache coverage.

How you can enhance LCP

  • Cut back TTFB.
  • Optimize useful resource load instances, for instance compressing photographs, serving them in numerous sizes, utilizing a CDN, and many others.
  • Optimizing CSS, for instance compressing, eradicating unused CSS and deferring non-critical CSS.
  • Shortening the Essential Rendering Path (CRP).
  • Deferring non-critical scripts and add scripts to the physique of the HTML doc.

Third Pillar (Time to Interactive) 🎬

You may be accustomed to JavaScript’s single thread nature, if not then this article may be an excellent useful resource for you.

💡 What’s a Foremost Thread?

The principle thread is the place a browser processes consumer occasions and paints. The browser makes use of a single thread to run a web page’s JavaScript, in addition to the Essential Rendering Path. The browser might not reply to consumer interactions if the primary thread is blocked/occupied by one other course of.

How you can enhance TTI

1. Minimizing Foremost thread’s work

We run most of our code on the primary thread. Lifting off the burden or delegating a few of this work to a different Service can enhance the efficiency of an online web page.

2. Debouncing Occasions

Delaying the execution of occasion handlers can enhance efficiency as a result of it helps the browser keep away from quick consecutive occasions. These occasions can block frames from finishing, and may trigger further and pointless structure work.

3. Net Staff

Net staff can be utilized to delegate complicated processes and run duties within the background in a separate thread.

4. Minification

Minifying and deferring non-critical CSS/JavaScript can enhance an online web page’s efficiency.

5. Code Splitting

Means the browser will solely obtain the JavaScript customers want on the time. For instance, let’s contemplate an online app with three pages, specifically dwelling, chat and notifications. Code-splitting permits you to obtain solely the JavaScript related to your property web page after which obtain the remaining belongings on-demand or when a consumer navigates to a web page that really wants.

6. Occasion Delegation

Propagating or effervescent up an occasion within the hierarchy of the DOM tree can enhance an online web page’s efficiency.

Extra Rendering Patterns

We have beforehand mentioned the 2 foremost rendering patterns, specifically Consumer Aspect Rendering (CSR) and Server Aspect Rendering (SSR). Now it is time to introduce some new rendering patterns that mix the very best of the 2 worlds.

SSR with Rehydration 🌨

This sample makes use of a pre-built DOM with parts rendered as HTML. The app then masses the remaining information within the consumer aspect.

CSR with Pre-rendering 🚧

This sample renders an app shell to static HTML throughout construct time .

Miscellaneous Efficiency Suggestions

  • Detect and get rid of pointless re-renders. Why did you render is a good library if you happen to’re constructing an app utilizing React.
  • Memoize values with React.memo/callbacks.
  • Analyze your packages if you happen to’re utilizing WebPack. WebPack Bundle Analyzer is a good selection. I’ve personally used it to enhance the efficiency of an NFT market.


Selecting the best instrument for the job is a important ability for each Software program Engineer. Software program decisions are often decided by the venture’s necessities.

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Assets 📚

I am at present engaged on just a few extra sagas. Let me know if you happen to’re focused on extra sagas within the feedback beneath 😁

NB: Half 2 of this text. will discover the sensible facets of internet rendering efficiency. I made a decision to interrupt it into two components as a result of I do not need to overwhelm the reader.

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Enjoyable Reality: This text’s story line was impressed by

  • This Tweet
  • Lupe Fiasco’s The Cool.
  • Demon Slayer: Kimetsu no Yaiba.
  • Marvel Motion pictures (Thor, Spiderman and Thor 2).
  • Assault on Titan.

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