Digital performance has always been at the forefront of Google’s priorities, especially as web users demand increasingly frictionless browsing experiences. As we look ahead to 2025, one of the most notable updates to Core Web Vitals is the replacement of First Input Delay (FID) with a more comprehensive metric: Interaction to Next Paint (INP). This change reflects a deeper emphasis on overall responsiveness, underscoring Google’s evolving expectations for user-centric web design and performance.
Why Google Is Phasing Out First Input Delay (FID)
Introduced in 2020, FID served as an essential metric to capture the interactivity of a webpage, calculating the time between a user’s first interaction (like clicking a link or tapping a button) and when the browser responds. However, while FID was useful, it measured only the first interaction on a page. This often led developers to optimize only the initial impression, creating an incomplete picture of user experience.
Recognizing this limitation, Google has decided to introduce a more robust metric—Interaction to Next Paint (INP). Unlike FID, INP considers a range of user interactions throughout a session, essentially measuring the latency of all interactions and reporting the worst-case scenario, within reason. This allows developers to assess web responsiveness more accurately and holistically.
What Is INP and How Does It Work?
Interaction to Next Paint (INP) is a Core Web Vital that evaluates the time between a user interaction (such as clicks, key presses, or other discrete events) and the next time the page visually updates in response. Importantly, INP captures
- Event latency (the time the browser takes to process the input)
- Processing delays caused by JavaScript or other thread-blocking tasks
- Delays in rendering updates to the user interface
Unlike FID, which focused solely on the input delay, INP aims to provide a fuller picture by tracking how quickly the page responds visibly to user commands. In technical terms, INP marks the time between the start of a user interaction and the next time the browser paints after handling the event.
Google recommends that INP should remain under 200 milliseconds for a page to be considered highly responsive.
Key Differences Between INP and FID
Understanding the fundamental differences between INP and FID is critical for website owners, marketers, and developers preparing for 2025’s performance yardsticks.
| Metric | What It Measures | Scope | Focus |
|---|---|---|---|
| FID | Time from user’s first interaction to event processing | Only first interaction | Input delay only |
| INP | Time from user interaction to next visual update | All interactions (reports worst performance) | Input, processing, and rendering |
Why This Change Matters
This transition to INP is not merely a shift in measurement; it’s a reflection of today’s web behavior. Users interact with pages multiple times—not just once—and expect near-instantaneous feedback. FID often failed to highlight poor performance that occurred after the initial load, allowing under-optimized interactivity to slip through the cracks.
With INP, performance bottlenecks hidden in complex interfaces, JavaScript-heavy pages, or multi-step user flows become more visible. Websites that continue to measure only initial responsiveness risk falling behind as Google begins ranking based on overall performance beyond the load event.
2025 Core Web Vitals Playbook: Preparing for INP
With INP officially replacing FID as of March 2024 and expected to be fully institutionalized in 2025 ranking algorithms, developers and SEO professionals must adjust their strategies accordingly. Below is a focused playbook for ensuring your web experience meets this new standard.
1. Audit Current Interactions
Begin by using tools like Lighthouse, PageSpeed Insights, or WebPageTest to understand your existing INP performance. Be sure to examine interaction-heavy pages such as forms, filters, menus, and mobile navigations. These are often the primary culprits for degraded responsiveness.
2. Optimize Main Thread Work
Long tasks blocking the browser’s main thread can delay input processing and rendering. To mitigate this:
- Defer non-critical JavaScript
- Break up long JavaScript tasks using
requestIdleCallback()orsetTimeout() - Use web workers for offloading intensive computations
3. Improve Event Handling Efficiency
Assess how frequently and efficiently your event handlers run. Avoid attaching too many event listeners, and throttle or debounce high-frequency inputs like scrolling or resizing. Leveraging frameworks and libraries with efficient rendering systems can significantly reduce latency.
4. Prioritize UI Feedback
Ensure that the UI offers visible feedback immediately after input (like animations or loading spinners), even if the final response takes time. This alleviates perceived delays that could otherwise increase INP latency.
5. Monitor Field Data
Lab tools don’t always reflect real-user experience. Use field data sources like Chrome User Experience Report (CrUX) or integrate the web-vitals library into your website to gather real-time interaction delays. Focus particularly on the 95th percentile, which is used to report INP.
What Does This Mean for SEO?
Search Engine Optimization (SEO) is increasingly intertwined with user experience. With INP becoming a Core Web Vital, sluggish interaction responses will now more visibly impact search rankings. In other words, achieving fast load times (LCP) and visual stability (CLS) is no longer enough.
Interaction speed is now a UX and SEO concern. Google has repeatedly emphasized that page experience metrics translate directly into search performance—particularly on mobile. A slow INP can lead to high page abandonment, poor ranking, and reduced conversions, making it as essential as content quality and keyword relevance.
Future-Proofing Your Web Performance Strategy
As web technologies continue to evolve, it’s crucial for developers and business stakeholders to adopt a long-term mindset toward site performance. Transitioning to accommodate INP today means setting the foundation for:
- More responsive web interactions
- Higher customer satisfaction
- Improved accessibility and mobile performance
- Better SEO results in Core Web Vitals-driven algorithms
Ultimately, adopting INP isn’t just about meeting Google’s benchmarks—it’s about optimizing for what your users genuinely experience while interacting with your site.
Conclusion
The transition from First Input Delay to Interaction to Next Paint marks a pivotal moment in the evolution of web performance standards. As INP takes center stage in 2025’s Core Web Vitals, web teams must adapt their optimization and monitoring strategies to deliver comprehensive responsiveness across all user interactions. Those who succeed will not only appease Google’s search algorithms but also provide superior user experiences that build trust, loyalty, and engagement in an increasingly competitive digital landscape.
Make INP optimization a core component of your performance playbook—not just to meet standards but to lead in the web of tomorrow.
