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Website Speed Optimization Service: Faster Pages, Better Core Web Vitals, More Conversions

Updated September 2026 · Written and maintained by the Progression Agency strategy team

A website speed optimization service makes a site load and respond faster on real devices: fixing images, scripts, hosting, caching, fonts and code so that pages pass Core Web Vitals and visitors stop leaving. Progression Agency provides website speed optimization from New York for WordPress, Shopify, WooCommerce and custom sites across the United States and worldwide. This page explains what slows sites down, how speed is measured properly, what the fixes are in order of impact, what changes by platform, what a speed optimization service should deliver, and what it costs.

On this page · 13 sections
  1. Why speed matters, in numbers you can measure
  2. Measuring speed properly
  3. What slows sites down, in order of impact
  4. The fixes
  5. WordPress speed optimization
  6. Shopify and WooCommerce speed optimization
  7. Custom and framework sites
  8. Keeping a site fast after the project
  9. Speed and conversion: proving the payoff
  10. What a website speed optimization service delivers
  11. How to choose a speed optimization service
  12. What it costs: website speed optimization
  13. Related services and guides

The short answerMost slow sites have the same five problems: uncompressed images, too many scripts from plugins and tags, render-blocking CSS and fonts, slow hosting or no caching, and heavy themes. A website speed optimization service measures on real devices, fixes those in order of impact, and proves the result with before-and-after field data rather than a single lab score. The payoff is measured in conversion rate and rankings, not in a number on a test tool.

Ranges on this page are the planning figures Progression Agency publishes; a quote follows a written scope. Nothing here describes a named client or a measured result for one.

Why speed matters, in numbers you can measure

Slow pages lose visitors before content appears, especially on phones. Search engines use Core Web Vitals as a ranking signal and as a condition for some search features. Conversion rates move with load time on every site we have measured. We report speed in the metrics Google reports, taken from real visitors, and tie them to conversion rate. Our website maintenance page covers ongoing care; this page is the speed project.

Site owners search for a website speed optimization service, WordPress website speed optimization service, website speed optimization services, page speed optimization, site speed optimization, Core Web Vitals optimization, LCP optimization, INP optimization, speed up WordPress, Shopify speed optimization, WooCommerce speed, website performance optimization and a page speed expert. One project covers all of them.

Measuring speed properly

Speed metrics that matter
MetricWhat it measuresTarget
Largest Contentful Paint (LCP)When the main content appearsUnder 2.5 seconds for most visitors
Interaction to Next Paint (INP)How quickly the page responds to taps and clicksUnder 200 milliseconds
Cumulative Layout Shift (CLS)How much the page jumps around while loadingUnder 0.1
Time to First ByteHow fast the server respondsUnder 0.8 seconds
Total page weight and requestsHow much is downloadedAs low as the design allows
Field data versus lab dataReal visitors versus a test toolField data decides; lab data diagnoses

Google’s Core Web Vitals documentation defines the thresholds; we measure against the field data in Search Console and real-user monitoring, not against a single lab run.

What slows sites down, in order of impact

  1. Images: uncompressed, oversized, wrong format, no lazy loading.
  2. Scripts: tag managers, chat widgets, trackers, sliders and plugins loading on every page.
  3. Render-blocking CSS and fonts: everything waits for stylesheets and web fonts.
  4. Hosting and caching: slow servers, no page cache, no CDN.
  5. Themes and page builders: heavy markup and unused code.
  6. Third-party embeds: videos, maps, social feeds loaded eagerly.
  7. Database and server-side bloat on WordPress and WooCommerce.

The fixes

Image compression and modern formats with responsive sizes and lazy loading; script audit with removal, deferral and conditional loading; critical CSS and font optimization; page caching, object caching and a CDN; theme and builder cleanup; embeds loaded on interaction; database cleanup; and server upgrades where hosting is the constraint. Each change is measured so the report shows what moved the numbers.

WordPress speed optimization

WordPress sites accumulate plugins, page builder weight and theme scripts. The work is plugin audit, builder optimization, caching and CDN configuration, image pipeline setup, database cleanup and, where needed, a move to better hosting. Our WordPress development page covers the platform; our WordPress hosting guide covers hosting choices.

Shopify and WooCommerce speed optimization

Shopify speed problems come from apps and theme scripts; the work is app audit, theme optimization and image handling within the platform’s limits. WooCommerce adds database, cart fragments and hosting concerns. Our Shopify agency page and ecommerce website design page cover the platforms.

Custom and framework sites

Sites built on modern frameworks need bundle analysis, code splitting, server-side rendering or static generation decisions, image components and caching strategy. The measurements are the same; the fixes are in the build.

Keeping a site fast after the project

Speed regresses as plugins, tags and images are added. A monitoring setup with alerts, a rule for adding scripts, and a quarterly check keep the gains. It is included in our maintenance plans.

Speed and conversion: proving the payoff

We record conversion rate and the field metrics before the project and after, by device, so the result is a business number rather than a score. Where traffic allows, changes are rolled out in a way that lets the effect be read.

We record conversion rate and the field metrics before the project and after, by device, so the result is a business number rather than a score.

What a website speed optimization service delivers

  1. Audit with field and lab data by page type and device.
  2. Prioritized fix list with expected impact.
  3. Implementation on a staging copy, then production.
  4. Before-and-after report with field metrics and conversion rate.
  5. Monitoring and a script-addition rule.
  6. Documentation of what was changed and why.

How to choose a speed optimization service

  • Ask whether they measure field data or only a test-tool score.
  • Ask for a before-and-after report from a past project.
  • Ask how they handle plugins and tags your marketing depends on.
  • Ask whether work is done on staging first.
  • Ask what happens after the project to keep the site fast.

What it costs: website speed optimization

Website work is priced by the number of templates, the content that has to be produced and the systems that must connect, not by page count. For website speed optimization, the ranges below are the planning figures from our marketing agency pricing guide and website cost guide; a quote follows a written scope and a redirect map.

Website planning ranges (US figures)
ProjectSmall agency rangeWhat drives the number
Brochure site, 5–12 pages$8,000–$25,000Custom design versus template
Site plus content program$20,000–$45,000The content is the half that makes it rank
Service business site, 20–60 pages$18,000–$55,000Templates, integrations, content volume
Ecommerce, small catalog$20,000–$70,000Integrations and SKU count
Redesign of an existing site$9,000–$40,000Redirect map, content migration, platform change
Landing page, single$1,200–$4,000Offer strategy more than design
Website maintenance$150–$800 / monthUpdates, backups, security, minor edits

Every figure above is a planning range already published on this site; the quote for website speed optimization follows a written scope, and the same ranges apply across the United States and worldwide.

Pages on this site that sit next to website speed optimization and that a buyer usually reads alongside it.

Getting found in search

AI, AEO and what is changing

Paid media and lead generation

Websites and design

Choosing and working with an agency

Software and app development

Web development, platforms and hosting

Social, content and brand

By industry and by situation

Frequently asked questions

What is a website speed optimization service?
A project that measures a site’s real-world speed, fixes images, scripts, CSS, fonts, caching, hosting and code in order of impact, and proves the result with field metrics and conversion rate.
How much does website speed optimization cost?
Speed projects are priced within website work: typically $1,200–$4,000 for a focused optimization on a small site and more for large or ecommerce sites, with maintenance at $150–$800 per month to keep gains. Ranges are published; a fixed quote follows an audit.
What are Core Web Vitals?
Google’s metrics for loading (LCP), responsiveness (INP) and visual stability (CLS), measured from real visitors and used as a ranking signal.
Will speed optimization improve my rankings?
It removes a ranking penalty and qualifies pages for search features; it is not a substitute for content and links, but slow sites underperform.
Will it improve conversions?
On every site we have measured, conversion rate moves with load time, especially on mobile. We report the change.
What usually makes a site slow?
Uncompressed images, too many scripts and plugins, render-blocking CSS and fonts, slow hosting without caching, heavy themes and eager third-party embeds.
Do you work on WordPress?
Yes: plugin and builder audit, caching and CDN, image pipeline, database cleanup and hosting recommendations.
Do you work on Shopify?
Yes: app audit, theme optimization and image handling within Shopify’s limits.
Do you work on custom sites?
Yes: bundle analysis, code splitting, rendering strategy, image components and caching.
Will you remove plugins or tags I need?
No. Marketing tags and plugins you depend on are kept and loaded more efficiently; removals are agreed with you.
Is the work done on a live site?
On a staging copy first, then deployed to production with a rollback plan.
How long does a speed project take?
One to three weeks depending on platform and site size.
How do you measure results?
Field data from Search Console and real-user monitoring, lab data for diagnosis, and conversion rate before and after by device.
Do you need hosting changes?
Sometimes. Where hosting is the constraint we recommend a move and can handle the migration.
How do we keep the site fast afterward?
Monitoring with alerts, a rule for adding scripts and a quarterly check, included in our maintenance plans.
Can you fix a slow WooCommerce store?
Yes: database, cart fragments, caching rules for logged-in users and hosting.
Do you provide a report?
Yes, before-and-after metrics, what was changed and why, and documentation.
Do you work with sites outside New York?
Yes, across the United States and worldwide.
What if my theme is the problem?
We optimize it where possible and tell you in writing when a rebuild would cost less than patching.
What is the first step?
Send the URL. You get a field-data audit summary, a prioritized fix list and a fixed quote.

Planning a new site?Send the current URL, what the site has to do and when you need it. You get a written scope, a page plan and a fixed price.

Get a fixed quote

Get a free marketing proposal

Tell us what you are trying to grow and we will come back with a plan, not a pitch deck. Same-day reply on weekdays.

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