Performance Glossary
WordPress Is a PHP Application. Tune It Like One
Your site is fast in a lab test and slow for logged-in users, and the reason is that only one of those two paths ever touches the cache.
The short answer
WordPress is the open-source platform behind roughly four in ten websites, and the most useful way to think about its speed is that it is a PHP application talking to a database — everything fast about it comes from not running that application.
Which is why the two questions that matter are what proportion of your requests the cache answers, and how long the remainder take to build. Everything else is downstream of those two numbers.
By the HostingFast team · Reviewed 12 August 2026
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The ecosystem is the reason it wins: tens of thousands of themes and plugins, a written answer to nearly every question, and tuned hosting available almost anywhere. The software costs nothing; hosting and any premium extras are where the money goes.
The self-hosted version — the one running on our plans — is yours outright: code, data and revenue. That is a materially different arrangement from wordpress.com, where the subscription tier decides what you are permitted to do.
Two request paths, two problems
An anonymous visitor on a cached page never touches PHP at all: LiteSpeed returns the stored response and the request is over in the time it takes to cross the network. A logged-in user, a basket holder or anyone hitting a search page gets the full application every time.
Measure both. Request a page anonymously, then request the same page with a session cookie, and compare. The gap between the two figures is the cost of your application, and it is invisible to any test that only ever loads the homepage logged out.
Where an uncached request spends its time
Broadly: PHP boot and plugin loading, then queries, then template rendering. A query monitoring plugin on staging attributes the time for you, and the result is nearly always concentrated — one plugin, or one query running on every page load rather than the handful it was written for.
The autoloaded options row is the standard first check, because it is read on literally every request. After that, look at what runs on admin-ajax or the REST API, since those paths are uncached by definition and often carry the heaviest work on the site.
Caching layers, in the order they help
Page caching removes the application from most requests and is the single biggest win. Object caching with Redis helps the requests page caching cannot serve, by holding query results in memory between them. OPcache sits underneath both, keeping compiled PHP ready to execute.
Add them one at a time and re-measure after each. Stacking three caching plugins at once is how sites end up with stale content, no attribution for the improvement, and nobody willing to remove anything in case it was the one that worked.
Proving it at the seventy-fifth percentile
Lab tools tell you whether the mechanism changed; field data tells you whether visitors felt it. The Core Web Vitals thresholds are read at the 75th percentile of real visits: LCP under 2.5 seconds, INP under 200 milliseconds, CLS under 0.1.
That percentile is the part people miss. A change that helps your fast visitors and leaves the slow quarter untouched moves your average and not your assessment, which is exactly the sort of optimisation worth catching before you celebrate it.
WordPress, described as the software it is
These entries treat WordPress as an application with a request path rather than as a website builder, because that is the framing in which its behaviour makes sense.
Every plan runs LiteSpeed with caching compiled in rather than bolted on, on NVMe storage, with WordPress Toolkit handling core and plugin updates.
- Cached and uncached measured apart
- Time attributed to a plugin or a query
- Caching layers added one at a time
- Field data at the 75th percentile
Why HostingFast
Standard on every plan
Two paths, measured separately
Anonymous and logged-in requests take different routes, and only one of them tells you anything about your application.
Attribution before optimisation
Finding the plugin or query that owns the time, rather than applying a list of general tips.
Layers explained in order
What page caching, object caching and OPcache each remove, and why they are added one at a time.
Thresholds quoted correctly
The published Core Web Vitals numbers, with the percentile they are actually read at.
The uncached paths named
admin-ajax and the REST API, where the heavy work usually hides from every homepage test.
Ownership stated plainly
What self-hosting gives you over a subscription tier, in terms of code, data and what you are allowed to do.
Quick Start
From order to online
- 1
Time the same page twice
Once anonymously, once with a session cookie. The difference between those two figures is the cost of your application, and it is the number worth working on.
- 2
Attribute the uncached time
Run a query monitor on staging and read which plugin and which query own the milliseconds. Optimising before this step is guessing.
- 3
Add one cache layer, then re-measure
Page cache, then object cache, then confirm OPcache is warm. One at a time, or no result can be attributed to anything.
Built In
Loaded onto every plan
- LiteSpeed compiled into the server, not a caching plugin bolted on afterwards
- WordPress Toolkit handling core and plugin updates for you
- NVMe on every tier — the entry plan runs the same drives as the top one
- PHP version selectable per site, switched from the control panel in seconds
- Staging you can clone, break and throw away before anything reaches live
- Daily backups with a self-service restore you run yourself from the panel
- Softaculous installers for WordPress and 400+ further applications
- Free SSL on every plan, reissued automatically well before it can expire
- Free migration by our own engineers, normally inside 24 hours
- A human on support at any hour, including for the awkward questions
Frequently Asked
What people ask us most often
Why is my site fast in a speed test and slow when I am logged in?
Because the test measures the cached path and your session skips it. Logged-in requests bypass page caching by design, so they pay the full cost of PHP and the database every time. Object caching with Redis is the layer that helps there, and it is worth measuring separately.
Does WordPress get slower as the site grows?
Not inherently, but its tables do. Revisions, transients, orphaned post meta and plugin log tables accumulate until queries stop being answered from memory. The growth is measurable in one query against information_schema, and the cleanup is usually the largest single improvement available.
Is staging an add-on, or part of the plan?
Part of it, on the plans that carry it. Clone the live site, do the work on the clone, then push it live once it behaves. That is the whole difference between hoping an update survives contact with production and knowing it does before a visitor ever meets it.
What does a migration actually involve at your end?
You hand over the login for your current host and our engineers move files, databases, mailboxes and configuration across, normally inside 24 hours. You test the copy on our hardware before DNS changes, so the old site keeps answering visitors right up until the new one is ready to take over.
Keep reading
Plugin
Third-party code running with your permissions, and what it costs in milliseconds.
WooCommerce
A storefront inside WordPress, and the uncacheable pages it introduces.
Best WordPress Hosting for Small Business
WordPress hosts ranked on first-byte time and what happens the week traffic triples.
DirectAdmin Reseller Hosting
Lightweight DirectAdmin reseller accounts at a lower monthly licence cost.
Web Hosting
cPanel hosting on NVMe with LiteSpeed, free SSL and a migration included.
Changing hosts? Run through our checklist first.
A straightforward sequence for a switch your visitors never feel: which files move first, how to shift email across without losing a single message, the right moment to repoint DNS, and the two mistakes behind almost all the downtime we get asked to rescue.
Serve the cached path without waking PHP.
LiteSpeed caching compiled into the server, NVMe on every tier, WordPress Toolkit for updates and a free migration to start.
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