Caching in Joomla

Caching in Joomla means storing rendered HTML, component views, and module output so the next guest request skips most database and PHP work. In Joomla 4, 5, and 6 you control three layers: Global Configuration System Cache (Off, Conservative, or Progressive), the System - Page Cache plugin for whole guest pages, and per-module Advanced caching. Handlers decide where copies live (File, APCu, Redis, or Memcached).

Official docs explain the switches. Deep technical posts explain com_cache internals. LiteSpeed magazine pieces cover one host stack. This guide is the operator map: which mode to pick by site type, what breaks Progressive and Page Cache, Redis and Memcached setup gotchas, how to clear and purge safely, and when caching alone cannot fix a slow EOL site. Infyways upgrades and tunes production Joomla from $149 with a free audit within 12 hours.

What you will learn

• The three cache layers and the order they win
• Conservative vs Progressive vs Page Cache with a decision table
• File, APCu, Redis, and Memcached: when each handler is right
• Exclusions for carts, forms, login, and personalised modules
• Clear vs purge, CLI clean, and stale-content fixes
• How LiteSpeed (or another edge cache) should sit beside Joomla cache
• A staging checklist and when to call Infyways

How Joomla caching is layered

Think of three increasing levels of aggressiveness. The first layer that can answer usually wins.

Layer	Where you set it	What it caches	Who it serves
System Cache (Conservative or Progressive)	System → Global Configuration → System → Cache Settings	Component views and modules (rules differ)	Mostly guests for core content views; access levels are part of the cache id
Module Advanced tab	Each module → Advanced	That module only (Use global or No caching)	Respects Conservative; ignored for guests under Progressive
System - Page Cache plugin	System → Manage → Plugins	Whole HTML page by URL	Guests only. Fastest built-in option

Primary sources: Joomla Cache user guide, caching views and modules (manual), and the LiteSpeed Cache and Redis magazine article.

Important: turning System Cache to Conservative does not by itself cache the full page. Full-page guest caching needs the System - Page Cache plugin enabled separately.

Conservative vs Progressive vs Off

Mode	What happens	Use when	Avoid when
Off	No view or module cache from Global Configuration	Debugging, template work, chasing a stale bug	Busy production brochure sites
Conservative (recommended default)	Caches eligible component views and modules that allow caching. Module "No caching" is respected	Almost every site: membership, forms, stores, multilingual	Never the wrong starting point
Progressive	For logged-off users, all modules are cached. Module "No caching" has no effect. Module output often shares a com_modules group file	Static brochure sites after careful staging tests	Menus that change by page, random modules, login-aware chrome, anything that must differ per Itemid

Myth to kill: Progressive is not "caching for logged-in users." Official docs are explicit that core view cachability rules do not flip that way. Progressive is more aggressive module caching for guests.

Classic Progressive failure: the wrong module appears on the wrong page because one cached module blob was reused across Itemids. If you see that, switch back to Conservative immediately.

System - Page Cache plugin

This is the fastest built-in path. On a hit, Joomla can return stored HTML before most of the site boots. It only serves guests. Logged-in visitors always get a fresh build so names, carts, and private menus stay private.

• Enable: System → Manage → Plugins → System - Page Cache
• It uses the same handler and Cache Time as Global Configuration
• Exclude menu items and URL patterns for anything dynamic
• Use Browser Caching sends browser cache headers. Leave it off unless you understand that visitors can keep a page after you clear server cache

Always exclude (or never page-cache): contact and other forms, search results, login and registration, carts and checkout, tokenised or one-time pages, and any URL that must reflect the current session. Editing an article does not always clear every page that embeds it. Clear the page cache group after content launches that must be instant.

Cache handlers: File, APCu, Redis, Memcached

Handler	Stores in	Best for	Watch outs
File	cache/ and administrator/cache/	Default on shared hosting and most single servers	Many tiny files on slow disks; purge expired regularly
APCu	PHP shared memory	Single server speed win for small items	Not shared across nodes; cleared on PHP restart
Redis	Redis server or Unix socket	Clusters, high traffic, LiteSpeed object cache stacks	Wrong host or socket causes 500s; change handler before killing Redis
Memcached	Memcached server or socket	Shared cache across web nodes	Often labelled experimental in host UIs; test persistence settings

Modern Joomla no longer relies on old handlers such as XCache or eAccelerator. If a host guide still lists them, ignore that part.

Redis tip from real support threads: if you disable System Cache while Redis is already unreachable, you can still get connection errors until you switch the handler back to File (or a working Redis), save, then turn caching off. Flush cache after handler changes.

Global Configuration fields that matter

Setting	Meaning	Practical default
System Cache	Off / Conservative / Progressive	Conservative
Cache Handler	Where items are stored	File, then Redis on capable hosts
Platform Specific Caching	Adds device type into the cache id	No, unless desktop and mobile HTML truly differ on the same URL
Cache Time	Lifetime in minutes (default 15)	15 for mixed sites; lower for news; higher for static brochures
Path to Cache Folder	Custom file path	Leave blank unless you know why

Module Cache Time is in seconds. Global Cache Time is in minutes. Mixing those units is a common misconfiguration.

Per-module caching

• Open the module → Advanced → Caching: Use global or No caching
• Set No caching for login status, live counters, random quotes, carts, and anything personal
• Under Progressive for guests, No caching is ignored. That is why Progressive breaks dynamic chrome
• Some modules declare a cache mode in code (static, itemid, and similar). A badly coded static mode can freeze wrong content even on Conservative

Breadcrumbs is a safe module to use when testing Conservative caching on staging.

Decision guide by site type

Site type	System Cache	Page Cache plugin	Handler	Notes
Brochure / marketing	Conservative (try Progressive only after tests)	On, with form pages excluded	File or Redis	Biggest easy win
Membership / ACL content	Conservative	On for public pages only; exclude member areas	File or Redis	Access levels belong in cache ids; still exclude personal dashboards
Multilingual	Conservative	On	File or Redis	Language is part of identity; clear cache after language or SEF changes
VirtueMart / Hikashop / carts	Conservative	On only for static CMS pages; exclude cart, checkout, account	File or Redis	Page Cache on cart URLs causes classic "empty cart" bugs
Heavy community / logged-in traffic	Conservative	Limited; focus on guest landing pages	Redis preferred on busy hosts	Page Cache helps guests only
LiteSpeed host	Conservative	Often rely on LiteSpeed full-page; keep Joomla Conservative	Redis as object cache when offered	Magazine guidance: Conservative with LiteSpeed + Redis reduces conflicts

LiteSpeed, CDN, and Redis together

Edge page cache (LiteSpeed Cache for Joomla, Cloudflare, or a reverse proxy) sits in front of Joomla. Redis or Memcached as the Joomla cache handler speeds object and view cache behind that. Do not stack three aggressive full-page systems without a purge story.

• Prefer Conservative when an external full-page cache is already on
• Let the edge plugin purge on article save when it supports automatic purge
• Use Redis for shared or high-traffic object cache, not as a substitute for excluding dynamic URLs
• ESI and logged-in edge features vary by LiteSpeed edition. Test on staging

Clear Cache vs Clear Expired Cache

Action	Path	Removes	Use when
Clear Cache	System → Maintenance → Clear Cache	Selected groups or everything	After template, override, or extension updates; stale homepage; debugging
Clear Expired Cache	System → Maintenance → Clear Expired Cache	Only past-lifetime items	Routine housekeeping so File handler folders do not fill forever
CLI clean	php cli/joomla.php cache:clean	All (or expired with the expired argument)	Deploy scripts and cron

With the File handler you can also empty cache/ via SFTP if the admin is down. That is equivalent to a full clear. Joomla cache is not a database table.

Step 1: Set a safe baseline on staging

1. Clone production to staging.
2. System → Global Configuration → System → Cache Settings: System Cache = ON - Conservative caching, Handler = File, Platform Specific Caching = No, Cache Time = 15.
3. Save. Browse as a guest. Confirm pages load and dynamic modules still update.
4. Only then introduce Redis or Progressive on a second staging pass.

Step 2: Enable Page Cache with exclusions

1. Enable System - Page Cache.
2. Exclude contact, search, login, cart, checkout, and account menu items.
3. Leave Use Browser Caching off for the first week.
4. As a guest, load a public article twice. Confirm a cache/page entry appears when using the File handler.
5. Edit that article, clear the page group, and confirm the front end updates.

Step 3: Tune modules and handlers

1. Set personal or random modules to No caching (Conservative only).
2. If the host offers Redis, set handler to Redis, enter socket or host, port 0 for Unix sockets when required, save, then Clear Cache.
3. Retest guest and logged-in paths, forms, and checkout.
4. Optional: try Progressive only on a static brochure clone. Revert at the first wrong-module symptom.

Step 4: Production cutover and monitoring

• Apply the proven staging settings during a low-traffic window
• Clear Cache after deploy
• Watch Core Web Vitals and server CPU for a week
• Schedule Clear Expired Cache or CLI purge if you stay on File
• Document exclusions so the next editor does not enable Page Cache on checkout

Troubleshooting stale or broken cache

Symptom	Likely cause	Fix
Old article text on guests	Page Cache still holding URL	Clear page group; shorten Cache Time if launches are frequent
Wrong module on a page	Progressive guest module cache	Switch to Conservative; clear com_modules
Empty cart or stuck form	Page Cache on dynamic URLs	Exclude those menu items and URLs; clear page cache
Redis connection 500 after "turning cache off"	Handler still Redis while server is down	Set handler to File while Redis is up, save, then disable caching
Logged-in users see no speed gain from Page Cache	By design	Rely on Conservative + Redis; Page Cache is guest-only
Mobile gets desktop chrome	Platform Specific Caching off while serving different HTML	Enable only if HTML truly differs; prefer one responsive template

Related reading: Joomla upgrade issues and fix Joomla update errors when cache problems appear after a version hop.

When caching is not enough

Cache multiplies a healthy stack. It does not replace an unsupported Joomla 3 site, an abandoned template full of blocking scripts, or PHP that the host is about to retire. If Time to First Byte stays poor after Conservative + Page Cache on staging, fix the CMS and template path first.

Infyways runs that path as a service:

• Free compatibility and performance audit within 12 hours
• Fixed packages from $149 small / $299 medium / custom for stores and clusters
• 100+ JED extensions in-house when a cache-hostile extension needs a rebuild
• Staging-first cutover and 30 days of post-launch support on defects we introduce

Start: Joomla Upgrade Services.

What thinner articles leave out

Topic	Typical post	This guide
Versions	Joomla 3 or 4 screenshots only	Joomla 4 / 5 / 6 settings that still apply
Conservative vs Progressive	One paragraph or a myth about logged-in users	Decision table + Progressive failure mode
Page Cache	"Turn the plugin on"	Guest-only rule, exclusions, browser caching warning
Handlers	File only, or outdated APC lists	File, APCu, Redis, Memcached with cluster notes
Edge cache	Missing or vendor-only	LiteSpeed + Redis layering with Conservative default
Operations	Clear Cache button	Clear vs purge, CLI, deploy hygiene
Site types	Generic speed claims	Brochure, ACL, multilingual, cart matrix
Next step	Affiliate plugin link	Staging steps + Infyways audit from $149

Key takeaways

1. Start with Conservative caching. Add System - Page Cache for guests with strict exclusions.
2. Progressive is optional and dangerous for dynamic modules. It is not "logged-in caching."
3. Full-page cache is a separate plugin. Global System Cache alone is not full-page cache.
4. File is fine for most sites. Redis or Memcached help clusters and high traffic.
5. Global Cache Time is minutes. Module Cache Time is seconds.
6. Clear the page group after launches that must be instant. Purge expired on File hosts.
7. Edge cache plus Joomla Conservative plus Redis is a common modern stack. Test purge behaviour.
8. If the site is EOL or template-bound, upgrade first. Cache cannot patch an unsupported core.