Each page compares Solid Objects with one tool on one real task. Each page says when the other tool is the better choice. The Solid Objects actor and effect code on each page runs in the test suite.
| Page | The other tool | The task |
|---|---|---|
| Solid Queue limits_concurrency and Solid Objects | Solid Queue, the Rails 8 default job backend | Ordered billing sync for each customer |
| GoodJob concurrency controls and Solid Objects | GoodJob, a PostgreSQL job backend | Ordered billing sync for each customer |
- The whole rule fits in one request: use a row lock (
with_lock), a constraint, or a short transaction. - Independent background work: use a job queue such as Solid Queue or GoodJob.
- One job at a time for each key, order not important: use the concurrency controls of your job queue.
- Order for each key, state for each key, reminders, and recovery after a restart: use an actor for each key.
The problem guides start from the same choices:
- Prevent race conditions in Rails
- Run jobs in order for each customer in Rails
- Expiring reservations
- Save state and queue work together
Solid Objects 1.0.0 shipped on October 13, 2026. One first-party application with more than 100,000 users runs it in production. That is a count of users, not a measure of load. See versioning and maintenance and continuity.