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What Is Time to First Byte (TTFB) and 5 Ways to Optimize It

  • 6 min read

Time to First Byte (TTFB) is a measure taken from the moment a user’s browser makes a request to a server to the time the browser receives the first byte of data from the server. It’s a useful metric for understanding the responsiveness and speed of a web server or network. 

TTFB includes the time taken to establish a connection, send the HTTP request, and start receiving the response. Measuring TTFB is critical for web performance analysis. A lower TTFB means a website’s content starts loading quicker, enhancing the user experience. Factors such as network latency, server load, and website optimization can influence TTFB.

This is part of a series of articles about real user monitoring.

In this article, you will learn:

Why Is TTFB Important? 

TTFB directly impacts the user’s perception of site speed. Fast TTFB contributes to quicker page loads, improving user satisfaction. Users expect websites to load instantly, so delayed TTFB can lead to increased bounce rates, lower user engagement, and as a result, decreased conversions and revenues.

While TTFB is one of the broader set of Core Web Vitals (CWV) published by Google, it is not one of the primary metrics included in the Google algorithm, which are LCP, INP, and CLS. However, TTFB is closely related to these metrics and can be a prerequisite for achieving a passing score for these metrics.

TTFB Components 

Here’s a breakdown of the factors measured in Time to First Byte.

Image credit: Web.dev

Time Taken to Send an HTTP Request

The first component is the time taken to send an HTTP request from the user’s browser to the server. This involves DNS lookup, establishing a connection, and sending the request. A fast, direct connection and optimized DNS services can reduce this time. Factors like geographical distance and network congestion can also affect this phase.

Time Taken to Process the Request

Once the server receives the HTTP request, it processes it. This involves querying databases, executing server-side scripts, and initiating backend tasks necessary to generate the response. Efficient code and server optimization can decrease processing time. Server capacity plays a role here. Overloaded servers or insufficient resources can cause significant delays.

Time Taken for the Server to Send the First Byte Back

The last component is the server sending the first byte of the response. This marks the end of the server’s processing and the beginning of data transfer back to the user’s browser. High-performing servers and optimized application code contribute to a quick response. Network speed and server bandwidth affect how quickly the data travels back to the user. Ensuring ample server resources can enhance this stage.

What Is a Good TTFB Score? 

According to Google, an adequate TTFB score is generally considered to be under 800 milliseconds. Achieving this target ensures a website is responsive and user-friendly.

Exceeding 800 milliseconds suggests room for improvement, while TTFB over 1800 milliseconds is considered poor. High TTFB may deter visitors, making optimization a priority for website owners aiming for superior performance and user experience.

How to Measure TTFB 

Here are some of the means that can be used to measure Time to First Byte.

Chrome DevTools

Chrome DevTools allows users to measure TTFB by inspecting the network tab. Here, loading times for each resource can be analyzed, including TTFB. This tool is effective for quick checks and identifying slow-loading resources. Using Chrome DevTools requires no additional installations, making it accessible for immediate performance evaluations. 

Source: Chrome Developers

WebPageTest

WebPageTest provides detailed insights into loading times, including TTFB, allowing for comprehensive analysis. It offers advanced settings, including testing from different locations and devices, giving a well-rounded view of a site’s performance. Its ability to simulate different scenarios helps identify potential areas for improvement, making it useful for web performance optimization.

Source: WebPageTest

GTmetrix

GTmetrix combines performance and loading time insights, offering a clear picture of a website’s speed, including TTFB. Customizable testing parameters and detailed reports make it a strong option for detailed analysis. With recommendations provided by GTmetrix, users can pinpoint specific areas needing optimization, streamlining the improvement process.

Source: GTmetrix

What Causes a Slow TTFB? 

There are several factors that can slow down Time to First Byte.

Insufficient Server Resources

A lack of server resources, such as CPU and memory, can lead to high TTFB. Demand exceeding supply slows down response times. Upgrading server components or optimizing server-side software can address this issue. Investing in scalable, high-performance server solutions ensures resources meet demand, optimizing TTFB and overall site speed.

Connection Issues

Connection issues, including poor server response and network latency, can increase TTFB. The physical distance between the user and server plays a role, as does overall network health. Choosing strategically located servers and ensuring robust connectivity options can mitigate connection-related delays, enabling a smoother user experience.

Long Redirect Chains

A long redirect chain can significantly slow TTFB, as each redirect adds delay. Reducing redirects optimizes response time, improving TTFB. Ensuring users and search engines reach the final destination with minimal redirects improves efficiency. Optimization involves identifying unnecessary redirects and streamlining the path to content, benefiting speed and SEO.

5 Ways to Improve TTFB for Your Website 

Here are some measures that can help you achieve the optimal Time to First Byte for a website.

1. Set Up a Cache Layer

A cache stores frequently accessed data, reducing server load and improving TTFB. Solutions like Varnish or built-in caching in content management systems can be effective. Caching responds to repeated requests faster by serving saved data rather than processing each from scratch.

Regularly updating cached content ensures it remains relevant, balancing performance with up-to-date information delivery.

2. Implement a CDN

A Content Delivery Network (CDN) stores site content in multiple locations worldwide, reducing the distance data travels to reach the user, thus improving TTFB. CDNs enhance content accessibility and reduce the server load.

Selecting a CDN that integrates well with your website infrastructure and content distribution needs can boost performance and reduce TTFB.

3. Use Minification and Compression

Minification and compression reduce file sizes of HTML, CSS, and JavaScript, leading to quicker processing and reduced TTFB. Tools like Gzip compress data for faster transmission over the network.

Applying these techniques optimizes bandwidth usage and speeds up content delivery, contributing to a more efficient TTFB and overall site performance.

4. Avoid Multiple Page Redirects

Excessive page redirects create unnecessary delays. Simplifying the path to content by reducing or eliminating redirects optimizes TTFB. Examining and restructuring redirect chains can improve speed.

Centralizing and managing redirects helps streamline access to content, benefiting the user experience and TTFB.

5. Update CMS, Plugins, and Themes

Keeping your content management system (CMS), plugins, and themes up to date ensures optimized performance and security. Updates often include optimizations that can improve TTFB by enhancing efficiency and fixing bugs that may slow down a site. Regular maintenance and updates are crucial to optimize TTFB and ensure a website runs smoothly, securely, and quickly.

Optimizing Core Web Vitals with Coralogix

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