> ## Documentation Index
> Fetch the complete documentation index at: https://docs.alterscope.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Defer alerts during quiet hours

> Set a daily window where non-urgent alerts wait instead of paging you, then arrive folded into a digest once the window ends.

Not every alert needs to wake you up. Quiet hours define a daily local-time window during which a rule's firings are held rather than delivered — and folded into a single digest-style message once the window ends, so nothing is silently dropped.

## 1. Set the window

Quiet hours take three fields together — start, end, and an IANA timezone — expressed as minutes since local midnight (`0`–`1439`):

```bash curl theme={null}
curl -H "Authorization: Bearer $ALTERSCOPE_API_KEY" \
     -H "Content-Type: application/json" \
     -X PUT -d '{
       "quiet_hours_start_min": 1320,
       "quiet_hours_end_min": 420,
       "quiet_hours_tz": "America/New_York"
     }' \
  "https://api.alterscope.org/v1/alerts/rules/$RULE_ID"
```

`1320` is 22:00, `420` is 07:00 — this rule goes quiet at 10pm and resumes at 7am, both in `America/New_York`. Because `start` (1320) is greater than `end` (420), the window wraps past midnight; if `start` were less than `end` it would be a same-day window instead (e.g. `540`→`1020` for 9am–5pm quiet hours).

```python python theme={null}
client.put(f"/v1/alerts/rules/{rule_id}", json={
    "quiet_hours_start_min": 22 * 60,
    "quiet_hours_end_min": 7 * 60,
    "quiet_hours_tz": "America/New_York",
})
```

<Note>
  All three fields are required together — sending only `quiet_hours_start_min` returns `400` (`quiet hours require start, end, and tz`). To clear quiet hours entirely, you currently have to recreate the rule without them; there's no dedicated "unset" shorthand.
</Note>

## 2. What happens to a fire inside the window

A condition match that would normally fire immediately is instead held — not discarded — for delivery once the window ends. Non-critical fires are the ones affected; the point of quiet hours is to stop non-urgent noise overnight, not to hide something you'd want to act on regardless of the hour.

You can see a held fire on the event log while it's waiting:

```bash curl theme={null}
curl -H "Authorization: Bearer $ALTERSCOPE_API_KEY" \
  "https://api.alterscope.org/v1/alerts/events?rule_id=$RULE_ID&status=suppressed"
```

Once the window closes, the held fire is delivered folded into a batched message alongside anything else that queued up during the same window — you get one notification summarizing the quiet period instead of one per fire.

## 3. Timezone validation

`quiet_hours_tz` is checked against the IANA timezone database at write time — an invalid zone name is rejected immediately with `400`, rather than silently failing to ever engage:

```bash curl theme={null}
curl -H "Authorization: Bearer $ALTERSCOPE_API_KEY" \
     -H "Content-Type: application/json" \
     -X PUT -d '{
       "quiet_hours_start_min": 1320,
       "quiet_hours_end_min": 420,
       "quiet_hours_tz": "Eastern"
     }' \
  "https://api.alterscope.org/v1/alerts/rules/$RULE_ID"
# 400: quiet_hours_tz is not a valid IANA timezone
```

Use full IANA names (`America/New_York`, `Europe/London`, `UTC`), not abbreviations or offsets.

## Troubleshooting

* **`400: quiet hours require start, end, and tz`**: partial-merge `PUT` still requires all three quiet-hours fields in the same request the first time they're set — you can't add `quiet_hours_tz` alone to a rule that has no start/end yet.
* **Alert arrived outside the window when I expected it deferred**: quiet hours suppress **non-critical** fires; a rule's severity is assigned by the platform based on its data source and conditions, not a field you set directly.
* **Window seems inverted**: `start > end` means an overnight window (wraps past midnight); `start < end` means same-day. `start == end` disables quiet hours entirely for that rule (treated as no window).
* **Nothing showed up after the window ended**: confirm the fire is actually recorded — `GET /v1/alerts/events?rule_id=$RULE_ID&status=suppressed` — and check your channel's delivery status once the digest goes out, same as any other fire (see [Troubleshooting](/recipes/manage-alert-rules#7-troubleshooting) in the rules guide).