KB / Memory / tech-durable-object-alarms-not-cron
Durable Object alarms are not Worker cron triggers
DO alarm() can schedule work without consuming the account-wide Worker cron cap
Cloudflare Durable Object alarm() wakes a DO at a chosen time. Alarms are not Worker [triggers] crons and do not count toward the account-wide 5-cron cap (tech-cloudflare-cron-triggers-five-per-account).
Workflow binding schedules are a different product and paid-only (tech-workflows-binding-schedules). On a Free plan, a DO alarm (or an external GitHub Actions POST) can start periodic work without a sixth Worker cron or a paid Workflow schedule.
Docs: Durable Object Alarms.