Every 30 Seconds

Use in your stack

{
  "schedule": {
    "cron": "0/30 * * * * ?",
    "timezone": "UTC"
  }
}

// 6-field: second minute hour day-of-month month day-of-week
@Scheduled(cron = "*/30 * * * * *")
public void everyThirtySeconds() {
    // ...
}

// Simpler for pure intervals:
@Scheduled(fixedRate = 30000) // milliseconds
public void everyThirtySecondsFixedRate() {
    // ...
}

Next runs

Pick a timezone to see when this expression fires next.

Variations

Common use cases

• Polling a queue or inbox twice a minute for lower latency than a 1-minute cron.
• Refreshing a cache or health status on a 30-second heartbeat.
• Emitting a keep-alive or liveness ping to a monitoring system.
• Flushing a metrics buffer downstream at a steady twice-per-minute rate.

Gotchas

• **Unix crontab cannot do this.** The 5-field format has no seconds field; its minimum interval is one minute. A common workaround is two crontab lines with `sleep 30` — but a seconds-aware scheduler is cleaner.
• In Spring, `*/30 * * * * *` is the 6-field form (seconds first) — not Unix's `*/30 * * * *`, which means every 30 *minutes*.
• In Quartz, use `0/30 * * * * ?` — `0/30` in the seconds field means "from second 0, every 30 seconds" (so it fires at :00 and :30 of each minute), and `?` fills the unused day-of-week field.
• `@Scheduled(fixedRate = 30000)` (Spring) or `tokio::time::interval` (Rust) expresses the same interval without a cron parser and is often the simpler choice.
• If a run can take longer than 30 seconds, prefer `fixedDelay` or an in-flight guard so runs don't overlap.

Frequently asked questions