Redis Caching in OpenCart 3.x: Setup and Tuning

A slow OpenCart is one of the most common complaints store owners have. One of the most effective ways to speed it up is Redis. Here it is, step by step.

Why Redis rather than file cache

Stock OpenCart uses a file cache in storage/cache/. Redis holds data in RAM, which is 10–100× faster to read than disk. The difference is especially clear on stores with 1,000+ products.

Step 1: install Redis

apt install redis-server php8.3-redis
systemctl enable --now redis-server

Check that Redis is listening on localhost:

redis-cli ping
# PONG

Step 2: configure redis.conf

maxmemory 256mb
maxmemory-policy allkeys-lru
bind 127.0.0.1
requirepass your_strong_password

Step 3: connect it to OpenCart

In config.php, change the storage driver:

define('CACHE_DRIVER', 'redis');
define('CACHE_HOSTNAME', '127.0.0.1');
define('CACHE_PORT', 6379);
define('CACHE_PASSWORD', 'your_strong_password');

Step 4: move sessions to Redis

In php.ini or the PHP-FPM pool configuration:

session.save_handler = redis
session.save_path = "tcp://127.0.0.1:6379?auth=your_strong_password"

Monitoring the hit rate

redis-cli info stats | grep keyspace_hits
redis-cli info stats | grep keyspace_misses

Target: a hit rate above 90%. Below that, raise maxmemory.

The result

Configured properly, Redis brings TTFB down from 800–1500 ms to 50–150 ms, and cuts load on MariaDB by 40–70%.

Want me to set up Redis for your OpenCart? Get a quote.