Most SEO companies do offer site speed optimization, but the scope of that work varies a lot from one provider to the next. Before you sign a contract, it helps to know what “site speed optimization” actually covers, where it sits inside a broader SEO engagement, and what the company can and cannot do without help from other people.
Why speed falls under SEO at all
Site speed became part of the SEO conversation because Google measures real visitor experience through Core Web Vitals. There are three metrics. Largest Contentful Paint (LCP) tracks how long the main content takes to appear, with a “good” score at 2.5 seconds or less. Interaction to Next Paint (INP) tracks how quickly the page responds when someone taps or clicks, with a good score under 200 milliseconds. Cumulative Layout Shift (CLS) tracks how much the layout jumps around while loading, with a good score under 0.1.
Google judges these using field data from real Chrome users at the 75th percentile, so at least three out of four visitors need a good score for a page to pass. Because the data comes from a rolling window of recent visits, changes you make take several weeks to show up in Search Console. Speed is one ranking signal among many, not a magic lever, but it also affects how many visitors stay long enough to convert. That overlap is why speed work usually lands on the SEO company’s plate.
What an SEO company typically delivers
When an SEO company says it handles site speed, expect a process rather than a single fix. The usual starting point is an audit using tools like PageSpeed Insights, Lighthouse, and Search Console’s Core Web Vitals report. The audit separates lab data from field data and identifies which pages fail and which metric is the problem.
From there, common deliverables include compressing and resizing images, converting them to modern formats such as WebP or AVIF, setting up browser caching, minifying CSS and JavaScript, removing render-blocking scripts, and reserving space for images and ads so the layout does not shift. Many companies also recommend or configure a content delivery network and review hosting performance, since a slow server response delays everything else.
A good SEO company will also re-test after changes and report progress against the Core Web Vitals thresholds, because some fixes that look fine in a lab tool still fail in real-world field data.
Where the limits are
Be realistic about what an SEO company can do alone. Speed problems often live in the website’s code, theme, plugins, or hosting setup. An SEO company can diagnose those issues and tell you exactly what needs to change, but the actual fix may require a developer, a theme change, or a hosting upgrade. Some SEO firms have developers on staff and will implement everything. Others will hand you a prioritized list and expect your web team to carry it out. Neither approach is wrong, but you should know which one you are buying.
Platform also matters. Speed work on a custom-built site, a WordPress site, and a hosted store such as Shopify look quite different, because you control different parts of each. Ask the company whether it has worked on your platform before.
Questions to ask before you commit
Ask whether site speed optimization is included in the main SEO package or billed separately. Ask whether the company will implement changes directly or only advise. Ask which tools and metrics it uses to measure success, and whether it reports on field data, not just lab scores. Ask roughly how long results take to appear, since the multi-week reporting delay is normal and a company that promises instant ranking gains is overpromising.
The short answer
Yes, site speed optimization is a service most SEO companies offer, and it is a reasonable thing to expect from a serious provider because speed ties directly into Core Web Vitals and user experience. The thing to confirm is depth: whether the company audits only, advises only, or actually does the technical implementation, and whether the work is included in your plan or priced as an add-on. Get those details in writing and you will know exactly what you are getting.