---
title: "TTFB"
description: "TTFB measures how long it takes for the first byte of a response to reach the browser after a request. See what a high TTFB reveals about server speed."
url: "https://nodea.io/en/glossary/ttfb"
lang: "en"
updated: "2026-07-13"
---

# TTFB

> TTFB (Time to First Byte) measures the time between a browser sending a request and receiving the first byte of the server's response.

**TTFB** (Time to First Byte) measures how long it takes for the very first byte of a server's response to arrive at the browser after a request is sent. It captures the delay before any content can begin rendering, combining the time spent resolving the address, establishing the connection and — most importantly — the server generating the response.

## What TTFB tells you

A high TTFB usually points to slow work happening on the server: expensive database queries, unoptimised application code, or the absence of [caching](https://nodea.io/en/glossary/cache-and-microcaching). Some of the delay comes from the network — the physical distance to the server and the time to set up the connection — but a large TTFB most often reflects how long the backend takes to produce the page. Because nothing can be displayed until the first byte arrives, TTFB sets a floor under how fast a page can feel.

## Improving TTFB

Reducing TTFB has a direct effect on perceived speed and user experience. Caching is the most powerful lever: serving a ready-made response from memory, for instance through a [reverse proxy](https://nodea.io/en/glossary/reverse-proxy) cache, skips the slow work of regenerating the page. A [CDN](https://nodea.io/en/glossary/cdn) shortens the network portion by serving content from a location near the user. On the application side, optimising queries, reducing heavy processing and using efficient code all help. TTFB relates to the broader [Core Web Vitals](https://nodea.io/en/glossary/core-web-vitals), since a slow server delays the metrics that measure loading experience. While TTFB is not the whole story — a fast first byte followed by heavy assets can still feel slow — it is a fundamental indicator of backend health, and keeping it low is one of the most effective ways to make a site feel responsive.

### What causes a high TTFB?

Usually slow server-side work: heavy database queries, unoptimised application code, no caching, or a distant server. Network latency and slow DNS resolution also contribute before the server even begins processing.

## Related

- [Core Web Vitals](https://nodea.io/en/glossary/core-web-vitals)
- [Cache and microcaching](https://nodea.io/en/glossary/cache-and-microcaching)
- [CDN (Content Delivery Network)](https://nodea.io/en/glossary/cdn)
- [Reverse Proxy](https://nodea.io/en/glossary/reverse-proxy)

---

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