Time to First Byte
Definition
How long it takes for a browser to receive the first byte of data from your server after requesting a page. A key server speed measure.
What is Time to First Byte?
Time to First Byte (TTFB) measures how long it takes from when a browser requests a page to when it receives the first byte of response data. It reflects your server's responsiveness and the efficiency of your backend processes.
While users don't see TTFB directly, it determines how quickly everything else can start loading.
Why TTFB Matters
Foundation of Page Speed
Nothing else can load until that first byte arrives. Slow TTFB delays everything that follows.
Server Health Indicator
High TTFB often signals server-side problems – overloaded servers, slow databases, or inefficient code.
SEO Factor
Google considers TTFB when evaluating page speed, which affects search rankings.
User Experience
While users experience the cumulative effect rather than TTFB alone, slow TTFB contributes to frustrating wait times.
What Affects TTFB?
Server Location
Greater physical distance means longer travel time for data. A UK user loading from a US server will have higher TTFB.
Server Performance
Shared hosting, underpowered servers, or high traffic loads all increase TTFB.
Backend Processing
Complex database queries, slow application code, or heavy processing adds time before the response starts.
DNS Resolution
Time spent looking up your domain's IP address counts toward TTFB.
SSL/TLS Negotiation
Establishing secure connections takes time, though the security trade-off is worth it.
TTFB Benchmarks
| Rating | TTFB |
|---|---|
| Good | Under 200ms |
| Acceptable | 200-500ms |
| Slow | 500ms-1s |
| Poor | Over 1s |
Improving TTFB
Use a CDN
Content Delivery Networks serve content from locations closer to users, dramatically reducing TTFB for static content.
Upgrade Hosting
Better servers respond faster. Quality hosting significantly outperforms budget alternatives.
Implement Caching
Server-side caching avoids regenerating pages for every request.
Optimise Backend
Database optimisation, code efficiency, and reducing unnecessary processing all help.
Keep Software Updated
Updated server software often includes performance improvements.