Gaurav Varma

Rails 8 introduces Solid Cache, a new caching backend designed to store cached data directly in your application database. Rails 8 also ships related database-backed infrastructure like Solid Queue for background jobs and Solid Cable for real-time messaging.

Caching has always been a critical part of building fast Rails applications. Traditionally, Rails apps relied on external systems like Redis or Memcached to store cached fragments, query results, and other temporary data.

Solid Cache changes this by offering a database-backed cache store, allowing many applications to run without external cache infrastructure.

What is Solid Cache?

Solid Cache is a new cache store implementation that stores cached entries inside the Rails application's database.

It works similarly to Redis-based caching but uses database tables to manage cached values.

This allows developers to use caching without running additional services.

Why Solid Cache?

While Redis is powerful, it introduces operational complexity:

separate server
infrastructure management
monitoring
scaling concerns

Solid Cache provides a simpler alternative for many apps.

Benefits include:

no extra infrastructure
transactional consistency
easier deployments
simplified development environments

For smaller applications or self-hosted deployments, this is a significant improvement.

Enabling Solid Cache

To configure Solid Cache, update the Rails environment configuration:

1config.cache_store = :solid_cache_store

Rails will automatically handle cache storage using the database.

Example fragment caching

Fragment caching works the same way as before:

1<% cache @article do %>
2  <%= render @article %>
3<% end %>

Rails stores the cached content using Solid Cache instead of Redis.

Example use cases

Solid Cache works well for many Rails caching scenarios:

fragment caching
view caching
API response caching
expensive query results
computed statistics

For very high traffic applications, Redis may still offer better throughput. However, Solid Cache works well for most typical Rails apps.

Summary

Solid Cache simplifies caching in Rails by allowing applications to store cached data directly in the database. By removing the need for Redis or Memcached, Rails 8 makes high-performance caching easier to deploy and maintain.

Rails 8 adds Solid Cache for built-in HTML fragment caching (no Redis needed)