Tips for Improving Time to First Byte (TTFB)

Time to First Byte (TTFB) is a measurement used to evaluate the performance of a website. It specifically measures the time from when a user makes an HTTP request to the moment when the first byte of the response is received by the browser.

When a user navigates to a website, their browser sends a request to the server hosting the website. The server then needs to receive the request, process it, gather the required data for the page, and start sending the response back to the browser. TTFB measures just the time it takes for that first chunk of data to arrive.

TTFB is measured in milliseconds (ms). A lower TTFB is better for performance. A TTFB under 100ms is generally considered good, while over 200ms is typically considered poor and slow.

The TTFB measurement encompasses the entire journey of the initial request. This includes:

• DNS lookup time – The time it takes to translate the domain name to an IP address
• Time to establish a TCP connection
• Time for the request to travel across the internet to the server
• Server processing time to gather the response
• Time to send the first byte of response back

So TTFB depends on client-side factors like DNS and latency, but more importantly on server-side factors like hosting speed and application efficiency. Optimizing these server-side factors is key to improving TTFB.

Monitoring TTFB is important because it directly impacts the user experience. A high TTFB means a longer delay before seeing page content load, which can cause users to

Why is TTFB Important?

Time to First Byte is a critical measurement of website performance because it directly impacts how quickly pages appear to load for users.

When a user requests a page, the browser cannot start rendering content until it receives the initial chunk of HTML from the server. So the TTFB determines when the browser can begin processing and displaying page content.

A high TTFB will therefore increase the loading time perceived by users. Even if the rest of the page loads quickly, a delay in TTFB will make the site feel sluggish. Users are very sensitive to delays – research has shown that even 250ms slowdowns can increase bounce rates.

This perception of slowness due to a high TTFB can lead to significant user experience impacts:

• Higher abandonment rate – Users will leave a slow-loading site before content displays.
• Lower conversion rate – Longer load times reduce conversions from visitors to customers.
• Higher bounce rate – More users will navigate away from the site after viewing only one page.
• Damage to brand reputation – Users will associate a slow site with poor quality or reliability.
• Loss of revenue – For ecommerce sites, every 1 second delay in load time can result in 7% loss in conversions.

By optimizing TTFB, sites can deliver a smooth, responsive user experience. Pages start loading quicker, allowing sites to retain users as well as gain search engine ranking benefits. Prioritizing TTFB optimization is therefore critical for overall business success. A fast TTFB helps create positive first impressions that keep users engaged.

Typical TTFB Values

Typical TTFB values vary depending on a number of factors, including the location of the server, the distance between the server and the user, the amount of traffic on the server, and the complexity of the web page. However, a good TTFB value is typically less than 100 ms. A TTFB value of 200 ms or more is considered to be slow.

Here are some things that can contribute to a high TTFB:

• A slow web host
• A congested network
• A poorly optimized database
• A large number of redirects
• The use of large or uncompressed images

Time to First Byte values can vary widely depending on the infrastructure and optimization of the website. However, there are some general guidelines for good vs poor TTFB:

• Good TTFB:

Under 100ms is considered good for most websites. Optimized sites should aim for sub-100ms TTFB for a responsive user experience. 50-70ms is excellent.

• Poor TTFB:

Over 200ms starts to be noticeable and feels sluggish to users. 300ms or higher is considered very poor and will significantly impact site performance.

Some key factors that influence TTFB include:

• Server location – Distance between the user and web server impacts latency. Closer servers have lower TTFB.
• Server load – High traffic sites or limited server resources increase queueing delays. Additional capacity is needed to handle load.
• Application efficiency – Complex sites with unoptimized dynamic content or databases are slower to respond. Code optimization helps.
• Caching – Reusing previously fetched content improves TTFB vs regenerating every page. Effective caching reduces database queries.
• Redirects – Each redirect adds a round trip time. Eliminating unnecessary redirects improves TTFB.
• Image optimization – Large uncompressed images slow down page generation. Compression and resizing helps.
• DNS lookup time – A slow DNS resolver adds delays before connecting to the server. A fast DNS service reduces latency.

With optimization across these areas, sites should target sub-100ms TTFB for a fast user experience. Setting up monitoring helps catch any TTFB regressions.

Tips for Improving TTFB

Use a fast web host

Your choice of web hosting provider has a major impact on website performance and Time to First Byte. Your host’s servers are responsible for receiving requests, fetching your site’s files from disk or cache, and sending the response back to visitors. So the speed and connectivity of your web host affects TTFB in a few key ways:

• Server processing power – Faster CPUs on your web host’s servers allow them to handle requests and compile dynamic pages quicker. Budget hosts often overload slow servers.
• Data center location – Having servers geographically close to your visitors reduces physical network latency. Distance adds delay as data travels between server and visitor.
• Quality connectivity – Fast, uncongested links between the web host and internet backbone allow rapid transit of request/response traffic.
• SSD storage – Solid state drives have faster read/write speeds than traditional hard disk drives when accessing files.
• Caching infrastructure – Effective caching mechanisms on the host side reduces database queries and repetition of CPU-intensive operations.
• Hypervisor optimization – Technologies like KVM hypervisors allow efficient resource allocation across virtual servers.

Use caching

Enabling caching is one of the most effective optimizations for reducing Time to First Byte. Caching works by storing static resources after the initial request and reusing those cached files to serve subsequent requests. This avoids having to regenerate the same content on every page visit.

There are two main types of caching:

• Browser caching – Resources like CSS, JS and images are cached locally on the user’s browser for a certain time period. This avoids re-downloading files on repeat site visits. Browser caching is enabled by setting cache headers.
• Server-side caching – Content is cached on the web server or CDN edge servers. This could be full page caching to reuse the HTML output, or caching of database queries, API requests, etc that assemble the page.

Server-side caching mechanisms include:

• CDNs – Content delivery networks distribute cached data globally. This reduces distance to users.
• Object caching – Data like database queries are cached in memory to avoid re-running code. Memcached and Redis are popular object caches.
• Opcode caching – Caches compiled PHP code to avoid re-processing on each request. Options include OPcache, Redis and APCu.

Proper caching configuration is vital for optimal TTFB. Test disabling caching to see its direct impact. Ensure caches remain invalidated when content is updated. Caching improves TTFB by serving requests faster.

Use GZIP compression

Gzip compression allows text-based files like HTML, CSS, JavaScript and images to be compressed into a smaller size before being transferred from the web server to the user’s browser. This directly improves Time to First Byte since less data needs to travel across the network.

When a web server receives a request, it can compress the response using Gzip or Deflate algorithms before sending it. The browser then decompresses the content after receiving it.

Gzip compression works by identifying repeating strings in text-based files and replacing them with smaller tokens. Some key benefits:

• Reduces file transfer size by up to 70% for HTML, and up to 90% for JS/CSS.
• Less data transfer means faster transit time over the network.
• Faster page load and TTFB as fewer bytes need to be sent.
• Also saves bandwidth usage for the hosting provider.

To enable Gzip, the web server needs the compression modules installed (like mod_deflate on Apache). It should be enabled by default on most modern web hosts. Test by inspecting the response headers – the Content-Encoding header will show gzip if enabled.

The optimal TTFB gains come from compressing HTML documents, JavaScript and CSS files which comprise most site content. Compression should be enabled both on your origin servers and CDN. Properly configured Gzip compression seamlessly reduces TTFB.

Optimize your database

For sites that rely on database calls to construct each page, an unoptimized database can significantly slow down response time and TTFB. Here are some tips for optimizing your database:

• Index tables properly – Adding indexes on columns used for lookups or joins speeds up query execution. But too many indexes can also bog down writes.
• Tune queries – Refactor any slow, unoptimized queries identified by your database profiler. Simplify joins, use caching, go parallel.
• Increase memory – Allocate more RAM to your database to keep hot data cached in memory rather than reading from disk.
• Cluster databases – Distribute reads and writes across nodes to share load. This allows scaling up database capacity.
• Vertical scale when needed – For busy databases, upgrade to more powerful hardware like faster processors and SSD storage.
• Compress data – Encoding reduces storage requirements and can improve I/O performance.
• Partition tables – Break up very large tables into smaller chunks to improve manageability.
• Defragment periodically – Reorganize data blocks on disk for faster reads.
• Clean up cruft – Remove duplicate, unused and obsolete data to streamline databases.

Proper database optimization tailored to your specific site’s data and query patterns can greatly speed up response times, reducing the TTFB consumed by database operations. Monitor database performance and tune regularly.

Use a CDN

A content delivery network (CDN) is a geographically distributed network of servers that accelerates content delivery and improves website performance. CDNs reduce TTFB by caching and serving static assets from edge servers closer to end users.

Some ways a CDN improves TTFB:

• Decreased distance – Resources are served from an edge server in close proximity to the user, reducing physical network latency.
• Improved connectivity – CDNs have high-speed dedicated links between nodes to minimize transit time.
• Caching at the edge – Frequently accessed content is cached locally on edge nodes, avoiding round trips to the origin.
• Load balancing – Requests are distributed across multiple servers to avoid bottlenecks.
• DDoS protection – CDNs absorb and mitigate DDoS attacks before they reach origin servers.
• Failover capabilities – If one region goes down, others takeover instantly. Minimizes disruption.

To use a CDN, your web host configuration is changed to point DNS for static assets to the CDN domain. Then the CDN will serve those files globally from nearby edge locations.

Testing with and without CDN enabled illustrates the TTFB gains. Average TTFB reduction could be 50-100ms for global users. CDNs also save web host bandwidth usage.

Avoid multiple page redirects

Redirects are when a web page returns an HTTP status code that causes the browser to load a different URL instead. Common redirects include 301 permanent redirects and 302 temporary redirects.

While redirects are useful for things like canonicalization and URL migrations, each redirect adds latency:

• An extra HTTP round trip is required to complete the redirect. This directly increases TTFB.
• Redirects daisy-chained together compound the delay as the browser is sent from URL to URL.
• Redirect loops caused by misconfigurations can exponentially magnify TTFB.

Best practices for optimizing redirects:

• Eliminate unnecessary redirects – Review old legacy URLs that may still redirect to new locations. Set up direct links.
• Combine chained redirects – Point old URLs directly at the final destination page rather than chaining redirects.
• Use 301s judiciously – Only use permanent 301 redirects when you know the change is permanent. 302s are better for uncertain changes.
• Monitor for redirect chains – Use ScreamingFrog or redirect map tools to visualize excessive redirect paths.
• Set up direct canonical URLs – Prevent duplicate content issues by redirecting to a single canonical URL.

Following redirects best practices will minimize unnecessary redirects and ensure each one is purposeful. Eliminating redirect bloat improves TTFB.

Stream markup to the browser

Typically a webpage will only start rendering once the full HTML document has been downloaded by the browser. Streaming markup allows progressive rendering by sending parts of the HTML to the browser as they are ready.

There are two main techniques for streaming markup:

• HTTP chunked transfer encoding – The web server chunks and streams content in increments, allowing the browser to parse each fragment as it is received.
• Server-Sent Events (SSE) – The server uses SSE to open a persistent connection and continuously push partial HTML segments.

Streaming benefits:

• Browser can start parsing and displaying page content faster, without waiting for full HTML.
• Creates perception of faster load and TTFB even if overall response is the same size.
• Useful for very long pages or pages with late-loading components.

Implementation requires changes to the backend code to break up response generation rather than buffering the full output. SSE is not supported on all browsers so fallback is needed.

When done correctly, streaming markup results in a more responsive experience by getting content on screen quicker. Users perceive faster TTFB when rendering starts sooner.

Use a service worker

A service worker is a script that the browser runs in the background, separate from a web page, opening up options for performance optimizations like caching.

Some ways service workers can improve TTFB include:

• Precaching assets – Static resources like CSS, JS and images can be cached on initial service worker install. For return visitors, cached assets are served faster than going to network/server.
• Caching HTML – Fully cached pages can be served instantly from the service worker cache without any network requests.
• Cache fallback – Network requests are tried first, but if TTFB is too high, the service worker can fall back to the cached version.
• Proxy cached data – Instead of directly serving cached files, the service worker can proxy cached responses from the server back to the page.
• Fetch events – The service worker can intervene on network requests to check cache before fetching from network.

The main challenges with service workers include compatibility (not supported on all browsers) and complex caching logic. When implemented correctly, TTFB can be greatly reduced by serving from locally cached responses.

Use 103 Early Hints for render-critical resources

The HTTP 103 status code allows a server to provide “early hints” to the browser about origin resources that will be needed to render the page. This enables faster time-to-first-byte.

When a browser requests a page, the server can include an “Early-Hints” header in the response that lists high priority resources like:

• CSS files required to render page layout
• JavaScript files needed for functionality
• Web fonts that must be loaded
• Logo image

The browser will then immediately start requesting these critical resources in parallel, without waiting for the full HTML response.

Benefits:

• Browser can discover and load render-blocking assets faster
• Resources most crucial to TTFB are prioritized
• Waterfall shifted left, improving TTFB
• Faster Start Render time and visual loading

Servers must be configured to identify and return essential early hints for each page. Support is still limited but growing across browsers. When leveraged correctly, 103 hints allow faster first render while the rest of the page loads.

Conclusion

Optimizing your website’s TTFB should be a priority, as high TTFB directly translates into slower loading speeds perceived by users. TTFB determines how quickly your pages appear responsive when loaded in a browser.

There are two main areas to focus on for improving TTFB – optimizing your server-side environment and employing client-side techniques.

On the server side, use a high performance host, implement caching, compress assets, stream partial responses, and optimize databases and code. CDNs also accelerate content delivery from edge locations.

On the client side, leverage browser caching, service workers, HTTP/2 multiplexing, and tools like Early Hints. Monitor TTFB regularly and make incremental improvements.

With a faster TTFB, pages load quicker and feel more responsive. Users are more likely to stay engaged with a site that loads rapidly. TTFB optimizations enhance user experience and can improve conversions and revenue. Delivering fast Time to First Byte should be an ongoing priority as part of a comprehensive performance strategy.