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@sendilkumarn

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@sendilkumarn Parker Solar Rover 635,266 km/h

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@sendilkumarn

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@sendilkumarn

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@sendilkumarn

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@sendilkumarn

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@sendilkumarn And many more… Janky Sliders Shifting contents 7mb images 71 critical requests ie support CSS JS shenanigans Animations

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@sendilkumarn And many more… Janky Sliders Shifting contents 7mb images 71 critical requests ie support CSS JS shenanigans Animations

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@sendilkumarn Sendil Nellaiyapen High Performance Web Applications

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@sendilkumarn 🇮🇳 / 🇳🇱 Sendil Nellaiyapen

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@sendilkumarn Engineering Manager @ Uber 🇮🇳 / 🇳🇱 Sendil Nellaiyapen

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@sendilkumarn Engineering Manager @ Uber 🇮🇳 / 🇳🇱 Sendil Nellaiyapen Right now learning Zig-lang

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@sendilkumarn Engineering Manager @ Uber 🇮🇳 / 🇳🇱 Sendil Nellaiyapen Right now learning Zig-lang GDE Web Performance

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@sendilkumarn What would you like to see in the session?

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@sendilkumarn What would you like to see in the session? Code

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@sendilkumarn What would you like to see in the session? Code Light

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@sendilkumarn What would you like to see in the session? Code Common Light

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@sendilkumarn What would you like to see in the session? Code Common Light Rendering

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@sendilkumarn What would you like to see in the session? Code Common Light Rendering Saga

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@sendilkumarn How websites work? Browser Server

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@sendilkumarn How websites work? Browser Redirect GET / Server

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp HTML

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process HTML

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load HTML

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load Time To First Byte HTML TTFB

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@sendilkumarn Web Performance Terminologies TTFB TTI LCP FID FCP Main thread Prefetch Preload CLS TBT CWV Core Web Vital INP Req Res Jargon alert!!!

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@sendilkumarn Time To First Byte TTFB

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@sendilkumarn 0.3 - 3s human attention span

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@sendilkumarn

Hello World

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@sendilkumarn

Hello World

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load HTML

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load HTML JS

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load HTML JS CSS

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@sendilkumarn How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load HTML JS CSS Img

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@sendilkumarn Critical Resources How websites work? Browser Redirect GET / Server Cache DNS TCP TLS Resp Process Load HTML JS CSS Img

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@sendilkumarn So why TTFB matters?

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@sendilkumarn 71 average requests per page source

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@sendilkumarn Hosting

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@sendilkumarn • Tune your backend + optimise based on your hosting provider • Real world TTFB latencies https://ismyhostfastyet.com/ • Godaddy / Shopify / GitHub • Response header: X-Powered- By: XXXXXX Hosting

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@sendilkumarn Content Delivery Network

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@sendilkumarn Content Delivery Network • CDNs are your friend • They increase your capability • Modern technologies / compression • Cloud fl are / GCP / AWS

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@sendilkumarn Reduce the load in critical path. Improve TTFB

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@sendilkumarn Reduce the load in critical path. Improve TTFB

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@sendilkumarn TTFB

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@sendilkumarn Use caching anywhere and everywhere TTFB

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@sendilkumarn Use caching anywhere and everywhere Avoid multiple page redirects TTFB

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@sendilkumarn Use caching anywhere and everywhere Avoid multiple page redirects Use Service Workers TTFB

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@sendilkumarn Core Web Vitals CWV

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@sendilkumarn First/Last Contentful Paint FCP

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@sendilkumarn FCP First/Last Contentful Paint FCP

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@sendilkumarn FCP LCP First/Last Contentful Paint FCP

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@sendilkumarn FCP

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@sendilkumarn FCP

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@sendilkumarn 1712 Kb FCP

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@sendilkumarn Split & Budget FCP

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@sendilkumarn Load what is needed & Virtualise FCP

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@sendilkumarn Preload / Lazyload FCP

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@sendilkumarn FCP

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@sendilkumarn FCP

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@sendilkumarn Minify resources FCP

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@sendilkumarn Minify resources Eliminate render blocking resources FCP

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@sendilkumarn Minify resources Eliminate render blocking resources Preload / prefetch FCP

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@sendilkumarn Cumulative Layout Shift (CLS) CLS

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@sendilkumarn Cumulative Layout Shift (CLS) CLS

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@sendilkumarn CLS

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@sendilkumarn Avoid Mutations & Re-rendering CLS

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@sendilkumarn Optimise JS CLS

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@sendilkumarn CLS

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@sendilkumarn Add dimensions for your images CLS

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@sendilkumarn Add dimensions for your images Web Fonts CLS

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@sendilkumarn Add dimensions for your images Web Fonts Animations (without layout shift) CLS

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@sendilkumarn Interaction to Next Paint (INP) INP

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@sendilkumarn Interaction to Next Paint (INP) INP

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@sendilkumarn INP

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@sendilkumarn FID First Input Delay Time To Interactive TTI INP

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@sendilkumarn INP

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@sendilkumarn Avoid long running tasks INP

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@sendilkumarn Avoid long running tasks Avoid using timers INP

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@sendilkumarn Avoid long running tasks Avoid using timers Avoid interaction overlap INP

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@sendilkumarn 45.7% Origins have a good CWV source CWV

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@sendilkumarn CWV

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@sendilkumarn Faster First Contentful Paint (<1.8s) CWV

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@sendilkumarn Faster First Contentful Paint (<1.8s) No Cumulative Layout Shift (< 0.1) CWV

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@sendilkumarn Faster First Contentful Paint (<1.8s) No Cumulative Layout Shift (< 0.1) Instant Interaction Next to Paint (<200ms) CWV

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@sendilkumarn

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@sendilkumarn Measure! Optimise!! Measure!!!

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@sendilkumarn WPOstats.com Performance improves Business FCP CLS INP Conversion

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@sendilkumarn 92% business thinks poor UX is costing them sales storyblok research weird fact

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@sendilkumarn Rendering

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@sendilkumarn Rendering

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@sendilkumarn Client Side Rendering CSR

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@sendilkumarn Traditional Web Applications

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@sendilkumarn CSR - what & how? Network Client

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@sendilkumarn CSR - what & how? Network Client GET /

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@sendilkumarn CSR - what & how? Network Client GET / GET /bundle.js

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@sendilkumarn CSR - what & how? Network Client GET / GET /bundle.js

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@sendilkumarn CSR - what & how? Network Client GET / GET /bundle.js Render (App)

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@sendilkumarn CSR - what & how? Network Client GET / GET /bundle.js Render (App) Fetch

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@sendilkumarn CSR - what & how? Network Client GET / GET /bundle.js Render (App) Fetch Load

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@sendilkumarn CSR - what & how? FCP Network Client GET / GET /bundle.js Render (App) Fetch Load

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@sendilkumarn CSR - what & how? FCP Network Client GET / GET /bundle.js Render (App) Fetch Load

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@sendilkumarn CSR - what & how? FCP Network Client GET / GET /bundle.js Render (App) Fetch Load

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@sendilkumarn CSR - what & how? FCP Network Client GET / GET /bundle.js Render (App) blocked Fetch Load

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@sendilkumarn CSR - what & how? FCP Network Client GET / GET /bundle.js Render (App) blocked Fetch Load

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@sendilkumarn CSR - what & how? FCP TTI Network Client GET / GET /bundle.js Render (App) blocked Fetch Load

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@sendilkumarn CSR - Things to note

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@sendilkumarn Search Engine Optimisation CSR - Things to note

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@sendilkumarn Search Engine Optimisation Fetching Data CSR - Things to note

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@sendilkumarn Search Engine Optimisation Fetching Data Main thread CSR - Things to note

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@sendilkumarn CSR - Performance Optimisation

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@sendilkumarn Split & Budget JavaScript (170kb) CSR - Performance Optimisation

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@sendilkumarn Split & Budget JavaScript (170kb) Preload / Lazyload CSR - Performance Optimisation

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@sendilkumarn Split & Budget JavaScript (170kb) Preload / Lazyload Application Shell CSR - Performance Optimisation

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@sendilkumarn Static Rendering SR

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@sendilkumarn Build pages at compile time

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@sendilkumarn SR - what & how? FCP TTI Network Client

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@sendilkumarn SR - what & how? FCP TTI Network Client GET /

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@sendilkumarn SR - what & how? FCP TTI Network Client GET /

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@sendilkumarn SR - what & how? FCP TTI Network Client GET /

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@sendilkumarn SR - what & how? FCP TTI Network Client GET /

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@sendilkumarn SR - what & how? FCP TTI Network Client GET /

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@sendilkumarn SR - what & how? FCP TTI Network Client GET /

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@sendilkumarn SR - what & how? FCP TTI Network Client GET / JS optional

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@sendilkumarn SR - what & how? FCP TTI Network Client GET / JS optional

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@sendilkumarn SR - Things to note

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@sendilkumarn Faster FCP & TTI SR - Things to note

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@sendilkumarn Faster FCP & TTI Good for SEO SR - Things to note

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@sendilkumarn Faster FCP & TTI Good for SEO Build times SR - Things to note

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@sendilkumarn SR - Performance Optimisation

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@sendilkumarn Do not use it for dynamic / interactive site SR - Performance Optimisation

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@sendilkumarn Do not use it for dynamic / interactive site Hosting service SR - Performance Optimisation

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@sendilkumarn Do not use it for dynamic / interactive site Hosting service Pre-rendering SR - Performance Optimisation

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@sendilkumarn Server Side Rendering SSR

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@sendilkumarn Generate HTML on server as response

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@sendilkumarn SSR - what & how? FCP TTI Network Client

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page Server Rendering

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page Server Rendering

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page Server Rendering

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page Server Rendering

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@sendilkumarn SSR - what & how? FCP TTI Network Client GET /page JS Server Rendering

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@sendilkumarn Loading Start Fetches Data Uses 3rd party lib Generates HTML

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@sendilkumarn Receives HTML Only HTML with no interactions.

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@sendilkumarn Hydrates

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@sendilkumarn Finish Fetching Finish Loading Finish Hydrate Interaction

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@sendilkumarn SSR - Things to note

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@sendilkumarn SSR - Things to note Slower TTFB

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@sendilkumarn SSR - Things to note Slower TTFB Good for SEO

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@sendilkumarn SSR - Things to note Slower TTFB Good for SEO Server cost

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@sendilkumarn SSR - Performance Optimisation

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@sendilkumarn SSR - Performance Optimisation Reduce JS

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@sendilkumarn SSR - Performance Optimisation Reduce JS Minimize Roundtrip

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@sendilkumarn SSR - Performance Optimisation Reduce JS Minimize Roundtrip Hydration

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@sendilkumarn Optimised Rendering techniques

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@sendilkumarn Optimised Rendering techniques

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@sendilkumarn Progressive rehydration via Suspend

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@sendilkumarn PR - what & how? FCP TTI Network Client Render

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