Everything You Need To Know About Google’s New Core Web Vitals: TTFB and INP

Everything You Need To Know About Google’s New Core Web Vitals: TTFB and INP

In March 2024, Google made a significant update to Core Web Vitals that website owners cannot afford to ignore. The search giant replaced First Input Delay (FID) with Interaction to Next Paint (INP) and elevated Time to First Byte (TTFB) to a critical supporting metric. These changes fundamentally shift how Google evaluates website performance and, consequently, search rankings.

If you’re seeing declining rankings despite quality content, the culprit might be your Core Web Vitals scores. This comprehensive guide explains exactly what TTFB and INP are, why they matter, and how to optimize them for better search visibility and user experience.

What Are Core Web Vitals?

Core Web Vitals are Google’s standardized metrics for measuring user experience on websites. They’re part of Google’s broader “page experience” ranking signals and directly impact where your site appears in search results.

The Current Three Core Web Vitals (2024-2025):

1. Largest Contentful Paint (LCP): Loading performance – how quickly main content appears
2. Interaction to Next Paint (INP): Interactivity – how quickly page responds to user interactions (NEW)
3. Cumulative Layout Shift (CLS): Visual stability – how much content shifts as page loads

Critical Supporting Metric:

• Time to First Byte (TTFB): Server response speed – how quickly server sends first byte of data

Think of these as Google’s report card for your website’s user experience. Poor scores don’t just hurt rankings—they cost you visitors, conversions, and revenue.

Why Google Changed Core Web Vitals

Google replaced FID with INP because FID only measured the delay before the first interaction started processing—it didn’t account for how long the actual interaction took or how responsive the page remained during the user’s entire session.

INP provides a more comprehensive view of interactivity by:

• Measuring ALL interactions, not just the first
• Capturing the full interaction lifecycle (input delay + processing + rendering)
• Better representing actual user experience throughout the session

Google’s research showed that 90% of user time on a page is spent after initial load, making post-load interactivity critically important for user satisfaction.

Deep Dive: Time to First Byte (TTFB)

What Is TTFB?

Time to First Byte measures the time from when a user’s browser requests a page until it receives the first byte of data from the server. It’s essentially a measure of server responsiveness.

TTFB Includes:

• DNS lookup time
• SSL/TLS negotiation
• Request travel time to server
• Server processing time
• Response travel time back to browser

TTFB Scoring Thresholds

Score	TTFB Time	Status
Good	0-800ms	Green (Optimal)
Needs Improvement	800ms-1.8s	Yellow (Suboptimal)
Poor	Over 1.8s	Red (Critical Issue)

Why TTFB Matters

TTFB is the foundation upon which all other performance metrics are built. If your server takes 3 seconds just to start sending data, achieving good LCP scores becomes nearly impossible.

Business Impact:

• Amazon found every 100ms of latency costs them 1% in sales
• Google discovered 53% of mobile users abandon sites taking over 3 seconds to load
• Faster TTFB directly correlates with better search rankings

Common Causes of Slow TTFB

1. Slow Hosting/Server Performance

• Shared hosting with limited resources
• Underpowered servers for traffic volume
• Server geographic distance from users
• Outdated server software

2. No Server-Side Caching

• Every request regenerates entire page
• Database queries execute on every page load
• No object caching for frequent operations

3. Bloated Databases

• Years of accumulated data without optimization
• Missing database indexes
• Inefficient queries
• Too many database calls per page

4. Third-Party Scripts

• Server-side scripts that execute before page sends
• External API calls blocking rendering
• Slow third-party services

5. Poor CDN Configuration

• No CDN at all
• CDN not caching properly
• Incorrect cache headers

How to Improve TTFB

Quick Wins (Hours to Implement):

1. Enable Server-Side Caching

• WordPress: Use WP Rocket, LiteSpeed Cache, or W3 Total Cache
• Enable object caching (Redis or Memcached)
• Cache database queries
• Set appropriate cache expiration times

2. Optimize Database

• Remove post revisions and spam comments
• Optimize database tables
• Add indexes to frequently queried columns
• Clean up autoloaded options (WordPress)

3. Implement CDN

• Use Cloudflare (free tier available)
• Configure proper cache rules
• Enable Argo Smart Routing for faster connections

Medium-Term Improvements (Days to Implement):

4. Upgrade Hosting

• Move from shared to VPS or managed WordPress hosting
• Choose hosting with server locations near your audience
• Select hosts using latest PHP versions and LiteSpeed/Nginx
• Consider providers like WP Engine, Kinsta, or Cloudways

5. Reduce Server Processing Time

• Minimize plugins (WordPress) or extensions
• Defer non-critical functionality to after page load
• Use lazy loading for content below fold
• Optimize code and remove bloat

6. Optimize Third-Party Scripts

• Load analytics and tracking scripts asynchronously
• Delay non-essential scripts until after page interaction
• Remove unused third-party services
• Self-host critical scripts when possible

Deep Dive: Interaction to Next Paint (INP)

What Is INP?

Interaction to Next Paint measures the latency of ALL user interactions with a page—clicks, taps, keyboard inputs—throughout the entire visit. It captures how quickly the page visually responds to those interactions.

INP Measures Three Phases:

1. Input delay: Time from user action to when browser can start processing
2. Processing time: Time for event handlers to run
3. Presentation delay: Time for browser to paint next frame showing result

INP reports the worst interaction latency during the page visit (excluding outliers).

INP Scoring Thresholds

Score	INP Time	Status
Good	0-200ms	Green (Excellent responsiveness)
Needs Improvement	200-500ms	Yellow (Noticeable lag)
Poor	Over 500ms	Red (Frustrating user experience)

Why INP Matters

Users expect instant feedback when they interact with a page. Delays between clicking a button and seeing a response create frustration and abandonment.

User Perception Research:

• Under 100ms: Instantaneous (users don’t notice delay)
• 100-300ms: Slight perceptible delay but acceptable
• 300-1000ms: Feels sluggish; users notice
• Over 1000ms: Users assume something is broken

Google’s research shows that sites with good INP scores see 24% lower bounce rates and 13% higher conversion rates.

Common Causes of Poor INP

1. Long JavaScript Tasks

• JavaScript blocks main thread during execution
• Large scripts take too long to parse and execute
• Heavy computations blocking user interactions

2. Too Many Third-Party Scripts

• Analytics tools competing for resources
• Ad networks injecting heavy scripts
• Chat widgets, social media buttons, tracking pixels
• Each script potentially blocking interactions

3. Inefficient Event Handlers

• Click handlers doing too much work
• No debouncing or throttling on scroll/resize events
• Synchronous operations in event callbacks

4. Large DOM Size

• Pages with thousands of DOM nodes
• Browser struggles to update large DOM trees
• Slow rendering after interactions

5. Render-Blocking Resources

• CSS and JavaScript blocking paint
• Large stylesheets taking time to parse
• Fonts loading synchronously

How to Improve INP

Quick Wins (Hours to Days):

1. Reduce Third-Party Scripts

• Audit all scripts with Chrome DevTools Performance tab
• Remove unused analytics, pixels, and widgets
• Load non-essential scripts after user interaction
• Use Google Tag Manager to control script loading

2. Break Up Long Tasks

• Split large JavaScript functions into smaller chunks
• Use setTimeout() to yield to main thread
• Implement requestIdleCallback() for non-urgent work
• Move heavy computation to Web Workers

3. Debounce and Throttle Events

• Don’t trigger functions on every scroll/resize event
• Use debouncing for search inputs (wait until user stops typing)
• Throttle scroll handlers to run maximum once per 16ms

4. Optimize Event Handlers

• Move complex logic outside event handlers
• Use event delegation instead of multiple listeners
• Defer non-critical updates until after interaction completes

Medium-Term Improvements (Weeks):

5. Reduce DOM Size

• Target under 1,500 DOM nodes
• Use virtualization for long lists (only render visible items)
• Lazy load content below the fold
• Simplify HTML structure

6. Optimize JavaScript Delivery

• Code-split large JavaScript bundles
• Load only necessary JavaScript for current page
• Use dynamic imports for route-based code splitting
• Minify and compress JavaScript files

7. Implement Performance Monitoring

• Use Chrome User Experience Report data
• Set up Real User Monitoring (RUM)
• Track INP in Google Analytics 4
• Monitor performance degradation over time

8. Optimize CSS

• Remove unused CSS
• Split CSS by route/page
• Inline critical CSS
• Defer non-critical stylesheets

How to Measure Core Web Vitals

Tools for Testing:

1. Google PageSpeed Insights

• URL: https://pagespeed.web.dev
• Provides both lab and field data
• Shows mobile and desktop scores
• Offers specific optimization recommendations

2. Google Search Console

• Core Web Vitals report shows real-user data
• Identifies which pages need improvement
• Groups issues by similarity
• Tracks improvements over time

3. Chrome DevTools

• Performance tab for detailed analysis
• Lighthouse audits for comprehensive testing
• Network tab for TTFB diagnosis
• Coverage tab to find unused code

4. WebPageTest

• URL: https://webpagetest.org
• Test from multiple locations
• Advanced waterfall charts
• Video comparison of page loads

5. Third-Party Monitoring

• GTmetrix for regular monitoring
• Pingdom for uptime and speed tracking
• New Relic or Datadog for enterprise monitoring

The Connection Between TTFB and INP

While TTFB and INP measure different aspects of performance, they’re interconnected:

• Fast TTFB enables fast LCP: Quick server response means content loads faster
• Fast initial load improves INP: Less JavaScript parsing on load means main thread is freer for interactions
• Server-side optimization benefits both: Faster servers help TTFB; less server-rendered content helps INP

Think of TTFB as the foundation and INP as the user experience built on top. Both must be optimized for excellent overall performance.

Core Web Vitals and SEO Impact

How Much Do Core Web Vitals Affect Rankings?

Google confirmed that Core Web Vitals are a ranking factor, but:

• They’re one of hundreds of ranking signals
• Content quality and relevance still matter most
• Poor Core Web Vitals won’t sink great content, but good scores provide a competitive edge
• The impact is more significant for queries where multiple pages are similarly relevant

Real-World Impact Studies:

• Vodafone improved LCP by 31%, saw 8% increase in sales
• NDTV improved INP by 50%, saw 50% reduction in bounce rate
• Rakuten improved Core Web Vitals, saw 33% increase in revenue per visitor

Mobile vs. Desktop Core Web Vitals

Google uses mobile performance for ranking (mobile-first indexing), but most tools show both:

Mobile Challenges:

• Slower processors than desktop
• Cellular connections less reliable than WiFi
• Smaller screens require different loading strategies
• Limited memory affects JavaScript execution

Mobile Optimization Priorities:

• Reduce JavaScript execution time (biggest mobile impact)
• Optimize images aggressively
• Minimize third-party scripts
• Test on actual devices, not just emulators

Common Core Web Vitals Myths

1. Myth: “Perfect 100 PageSpeed score guarantees good rankings”
   Reality: PageSpeed Insights score is different from Core Web Vitals. Focus on the three vitals, not the overall score.
2. Myth: “Core Web Vitals only matter for new content”
   Reality: Google evaluates all pages. Old high-traffic pages may need more attention than new low-traffic ones.
3. Myth: “Desktop performance doesn’t matter”
   Reality: While Google uses mobile for ranking, desktop performance affects user experience and conversions.
4. Myth: “Once optimized, scores stay good”
   Reality: Performance degrades over time as sites add features, plugins, and content. Regular monitoring is essential.
5. Myth: “Only developers can improve Core Web Vitals”
   Reality: Many improvements require only configuration changes or plugin selection.

Creating a Core Web Vitals Optimization Plan

Phase 1: Assessment (Week 1)

• Run PageSpeed Insights on 10-20 key pages
• Check Google Search Console Core Web Vitals report
• Identify worst-performing pages and common issues
• Document current scores as baseline

Phase 2: Quick Wins (Weeks 2-3)

• Enable caching plugins
• Implement CDN
• Optimize images (compress, convert to WebP)
• Remove unused plugins/scripts
• Defer JavaScript loading

Phase 3: Medium Improvements (Weeks 4-6)

• Upgrade hosting if needed
• Optimize database
• Reduce DOM size on heavy pages
• Break up long JavaScript tasks
• Implement lazy loading

Phase 4: Advanced Optimization (Weeks 7-8)

• Code splitting for JavaScript
• Critical CSS inlining
• Custom performance monitoring
• A/B test performance improvements against conversions

Phase 5: Ongoing Monitoring

• Weekly Search Console checks
• Monthly comprehensive audits
• Performance budgets for new features
• Regular regression testing

Expert Help With Core Web Vitals Optimization

Optimizing Core Web Vitals requires technical expertise, performance monitoring tools, and ongoing maintenance. Google’s shift to INP and emphasis on TTFB makes professional optimization more valuable than ever.

At Capetivate, we help New England businesses achieve and maintain excellent Core Web Vitals scores through comprehensive performance audits, technical optimization, and ongoing monitoring.

Our Core Web Vitals optimization service includes TTFB optimization, INP improvements, LCP enhancement, and monthly performance monitoring to ensure your site maintains competitive rankings.

Explore our website optimization services or schedule a free performance audit to see where your site stands.