How do I configure Redis on shared hosting?

Thank you for trying QuantumCache!

Yes, you can configure Redis via wp-config.php, but there are a couple of important prerequisites.

1. Make sure Redis is actually available

On shared hosting, Redis only works if your host provides a Redis service, and
the PHP redis extension is installed (php-redis)

If that extension isn’t available, QuantumCache will automatically fall back to MySQL.

2. Basic wp-config.php setup

You can define your Redis connection like this:

define( ‘QUANTUMCACHE_REDIS_HOST’, ‘127.0.0.1’ );
define( ‘QUANTUMCACHE_REDIS_PORT’, 6379 );
define( ‘QUANTUMCACHE_REDIS_DB’, 0 );

(Optional)

define( ‘QUANTUMCACHE_KEY_PREFIX’, ‘mysite:qc:’ );
define( ‘WP_CACHE_KEY_SALT’, ‘your-unique-salt’ );

If these constants are set, they override anything configured in the plugin UI.

3. Store mode (important)

QuantumCache still uses the store mode setting:

auto (default): tries Redis → falls back to MySQL
redis: forces Redis (will fail if unavailable)
mysql: disables Redis

For most shared hosting setups, leave it on auto.

4. How to verify it’s working Run: wp quantumcache status
   Or check response headers (look for X-QC-Store: redis)

Short version:

1. Yes, wp-config.php works for Redis config
2. Redis must be provided by your host with php-redis enabled
3. Otherwise, QuantumCache will quietly fall back to MySQL

Thanks for reporting this.

There was an issue in the current build where “Clear all cache” wasn’t working correctly. That’s why the Entries/Tags values didn’t change.

I’ve fixed this and it will be included in the next release (0.1.7), which I expect to publish tomorrow.

Also, the “wp quantumcache” commands are part of that same upcoming release. They aren’t in the current version.

I appreciate you taking the time to test it. I’ve updated my automated tests accordingly.