Glossary Entry
What is OPcache?
OPcache without the jargon — the definition, the analogy, and why any site owner should care.
The short answer
OPcache keeps compiled PHP bytecode in memory, sparing every request the work of recompiling the scripts, which hands speed to any PHP site on the machine for nothing.
The rest of the page opens it up — the mechanics, why a site owner should care, and one concrete example of it at work.
By the Hosting & Domains team · Reviewed 18 August 2026
0
Jargon left undefined
100+
Entries, all cross-linked
Real
Working examples
Free
To read, always
Left to itself, PHP opens and compiles the source files again for each request. OPcache does that once, then keeps handing the result back until a file genuinely changes. Across something the size of WordPress, that saving applies to every uncached request, admin screens included.
It is on by default on decent hosting, ours included, which makes it something you confirm rather than configure. Whether it is running shows on any phpinfo page.
A way to picture OPcache
Leaving the finished translation on the stand instead of working through the entire play again before curtain-up. Curtain-up happens on time, and only a rewritten scene goes back to the translator.
Any analogy flattens the detail, naturally — but this one is solid enough to think with, and thinking is what a jargon buster is for.
Where it touches your own site
PHP performance rests on OPcache, invisibly. Even quick hardware feels sluggish without it, and sizing it properly is one of the quiet differences between a platform somebody tuned and one somebody merely turned on.
That, incidentally, is the bar for any technical term — not 'could I lecture on it' but 'would I recognise it as the answer to my problem'. For this one, you now would.
How it turns up day to day
Hundreds of PHP files come in behind every WooCommerce dashboard screen, and all of them run from precompiled bytecode. Compilation, which would otherwise have outweighed the real work, happened once and days ago.
Entirely unremarkable once you have seen it — which is the point: most hosting ideas are plain machinery behind an intimidating label.
How Hosting & Domains deals with it
You will meet it in the control panel and now and then in a support thread, usually already set correctly. If this one landed, the natural follow-ups are PHP, Cache, Redis and TTFB.
Order an annual plan and the first year of the name's registration is on us.
Why a hundred definitions were worth the writing
Sooner or later every confusing hosting term turns into a support ticket, so we defined the hundred commonest ones properly — once, in the same plain English we use with customers.
Order an annual plan and the first year of the name's registration is on us.
- 100+ entries, plain English all the way
- Ordinary analogies, working examples
- Neighbouring ideas linked together
- Written by our own support engineers
Why Hosting & Domains
Standard on every plan
Tied to real hosting
Examples name platforms you would genuinely use, never an abstract diagram on a whiteboard.
Stakes made explicit
More than what a thing is: the moments it turns out to be the answer to a problem you have.
This term, properly landed
OPcache defined, pictured by analogy and located in your own panel — recognise-level after a single read.
Cross-wired entries
Related terms point at each other, so one lookup compounds into working knowledge.
Clear about how deep to go
Most of these are recognise-level rather than operate-level, and every entry says which it is.
The next step, drawn out
Carry on into PHP and Cache — ideas rarely travel alone, so the neighbours are linked in.
Quick Start
Order placed to site online
- 1
Find it in your own account
Nothing teaches a hosting term faster than finding it in your own panel; five minutes of looking beats an hour of reading.
- 2
Check the defaults as they stand
Look at how your account has it configured. Nine times in ten the default is right, and a check turns the guess into certainty.
- 3
Chase the neighbouring terms
Hosting terms travel in groups — PHP, Cache and Redis finish this one's picture, each a two-minute read away.
Built In
Fitted to every plan
- DDoS filtering absorbed at the network edge
- SSH, Git and Composer on the developer plans
- WordPress Toolkit, with the updates seen to for you
- Staging copies for trying a change before it goes live
- PHP versions set per site from the control panel
- Webmail in the browser plus IMAP, POP and SMTP for any client
- Mailboxes that answer at the name you hold
- The name's first year included when you order annually
- 99.9% uptime as the target, watched around the clock
- Your existing site brought across by our engineers, at no charge
Frequently Asked
The questions that come up most
Do I have to configure OPcache?
On managed hosting, no, since it is switched on and sized for you as part of the platform. On a VPS you enable it in php.ini and give it a sensible memory allocation, which is about the highest-yield line you will write in that file.
Does OPcache do the same job as Redis?
No, because they work at different layers. What OPcache caches is compiled code, which is to say the instructions for working something out. What Redis caches is results, which is to say what those instructions produced last time round. A fully tuned PHP stack runs both, and neither replaces the other.
Will you move my existing site free of charge?
Yes. Open a ticket with the login for your current host and we bring the lot across — files, databases, mailboxes, configuration. You check the copy before DNS moves, and the old site keeps taking traffic right up to the moment the new one serves it, so nobody meets a gap.
Which control panel do accounts use?
cPanel, the panel the industry standardised on long ago. Every tutorial you find online will match what is on your screen, your backups restore onto any other cPanel host, and the skills stay useful for life. Plesk and DirectAdmin are available on particular plans if you prefer either.
Keep reading
Cache
A cache keeps hold of work already done, returning finished pages, query results and assets straight from m…
Redis
Put an in-memory store to work as an object cache and you have Redis, holding query results and computed va…
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