For my site, I use Redis in addition to PostgreSQL for these purposes: - User session storage - Asynchronous "queues" for background processing using Streams

For my site, I use Redis in addition to PostgreSQL for these purposes: - User session storage - Asynchronous "queues" for background processing using Streams (was able to eliminate RabbitMQ from my stack when I switched to this) - Rate-limiting with a GCRA (via https://github.com/brandur/redis-cell https://github.com/brandur/redis-cell) - Bloom filter checks, specifically for making sure people aren't using passwords in data breaches (via https://github.com/RedisBloom/RedisBloom https://github.com/RedisBloom/RedisBloom with data from https://haveibeenpwned.com/passwords https://haveibeenpwned.com/passwords)