TTFB (Time to First Byte)
Macro-semantics (site level)TTFB (Time to First Byte) is a web performance metric that measures the time elapsed between when a browser sends an HTTP request and when it receives the first byte of response data from the server. This metric affects crawl budget and Core Web Vitals by measuring how quickly your server responds to requests. Slow TTFB can cause Google's crawler to skip pages within its daily crawl budget.
In macro-semantics, TTFB directly impacts Cost of Retrieval. The faster your server responds, the more efficiently Google uses its budget for indexing valuable content. TTFB below 200ms is excellent, while TTFB above 600ms indicates server optimization is needed.
You can measure TTFB using Google PageSpeed Insights or Lighthouse. If it exceeds 400ms, consider implementing a CDN, server-level caching, or upgrading your hosting. Fast TTFB is foundational for crawl efficiency. Without it, even the best content may not get fully indexed as the crawler exhausts its budget before reaching all pages.