Scheduled Scans

recon-web can run scans on a cron schedule and automatically detect changes between consecutive scans of the same URL. When paired with notifications, this gives you a lightweight monitoring system for your websites.

Enabling scheduled scans

Add the following to your .env file:

SCHEDULE_ENABLED=true
SCHEDULE_URLS=https://example.com,https://another-site.com

That is all you need. The scheduler starts automatically when the API server boots.

Configuration

Variable	Default	Description
`SCHEDULE_ENABLED`	`false`	Set to `true` to activate the scheduler
`SCHEDULE_CRON`	`0 0 * * *`	Cron expression controlling scan frequency
`SCHEDULE_URLS`	(empty)	Comma-separated list of URLs to scan on each tick

Cron syntax

The SCHEDULE_CRON variable accepts standard five-field cron expressions:

┌───────────── minute (0-59)
│ ┌───────────── hour (0-23)
│ │ ┌───────────── day of month (1-31)
│ │ │ ┌───────────── month (1-12)
│ │ │ │ ┌───────────── day of week (0-7, 0 and 7 = Sunday)
│ │ │ │ │
* * * * *

Common examples:

Expression	Schedule
`0 0 * * *`	Daily at midnight (default)
`0 /6 * *`	Every 6 hours
`0 9 * * 1`	Every Monday at 09:00
`/30 * * *`	Every 30 minutes

Change detection

Each time a scheduled scan completes, recon-web compares its results against the most recent previous scan of the same URL. If any handler’s data changed — for example a DNS record was added, an SSL certificate was renewed, or a security header was removed — the changes are recorded.

Changes are classified by severity:

Severity	Icon	Examples
Critical	`[!!!]`	SSL certificate expired, security header removed
Warning	`[!]`	DNS record changed, new open port detected
Info	`[i]`	Whois registrar updated, tech stack version bumped

When notifications are configured, changes are dispatched immediately after detection. See the Notifications guide for setup instructions.

Kubernetes CronJob alternative

If you are deploying on Kubernetes, you can use a native CronJob instead of the built-in scheduler. This gives you Kubernetes-native retry policies, resource limits, and observability. See the Kubernetes deployment guide for a ready-made CronJob configuration in the Helm chart’s scanner section.