Your web server is taking a long time to start sending your page. Before a visitor sees anything at all, their browser is sitting and waiting. This often points to slow hosting or a server that is doing too much work to build each page.
On WordPress
Enable page caching with WP Rocket, W3 Total Cache, or LiteSpeed Cache. These store a pre-built version of each page so the server doesn't have to rebuild it for every visitor. Also, connect Cloudflare (free) to reduce the distance between your server and global visitors.
On Shopify
Shopify manages its own servers, so TTFB on Shopify is usually fast by default. If you're seeing a slow TTFB, it's likely caused by heavy Liquid templates or apps running server-side code. Audit your installed apps and remove unused ones.
Pro tip: Page caching is the single biggest lever for improving TTFB on WordPress. A cached page can respond in under 100ms — the same page without cache can take 500ms–2 seconds. Enable it first, then measure.
SiteSprout scans your site, tells you which issues you actually have in plain English, and keeps watch so nothing breaks silently.
Scan your site free