TTFB (Time To First Byte)
TTFB (Time To First Byte) is a metric that measures how much time passes from the browser sending a request to receiving the first byte of the response from the server.
Simply put:
How quickly the server starts responding to the user.
How it works
When a user opens a website:
- The browser sends a request to the server
- The server processes the request
- The server sends the first byte of data
👉 The time up to this moment is the TTFB.
What TTFB consists of
TTFB includes:
- DNS query time (locating the server)
- Connection establishment (TCP/SSL)
- Server request processing time
- Network latency
Why TTFB is important
- Affects website loading speed
- Affects SEO (search engines consider speed)
- Affects user experience
- Affects conversion rates
Normal values
- < 200 ms — excellent
- 200–500 ms — normal
- > 500 ms — there are problems
How to improve TTFB
- Use fast hosting
- Configure a CDN
- Optimize server-side code
- Cache data
- Reduce server load
- Use modern protocols (HTTP/2, HTTP/3)
Example
If a user opens a site and the first response arrives after 800 ms:
TTFB = 800 ms → this is slow and requires optimization.
Key takeaway
TTFB is a metric that shows server response speed. The lower the TTFB, the faster the site starts loading, and the better the user experience and SEO.
