Cron Jobs

Background jobs run on scheduled intervals to handle SSL monitoring, notification delivery, and obligation recurrence. Configured via Vercel Cron or compatible scheduler.

Background Job Architecture

1. Scheduling

Vercel Cron triggers endpoints at configured intervals

2. Execution

Route handlers process jobs server-side

3. Queue Management

Database-backed queues with locking prevent duplicate processing

SSL Certificate Scan

Checks SSL/TLS certificates for all monitored domains and stores results.

Every 12 hours

0 */12 * * *

Endpoint: /api/cron/ssl-scan

Actions

1Retrieves all active domains from database
2Performs TLS handshake for each domain
3Parses certificate details (issuer, validity, SANs)
4Stores check results with status
5Creates notification events for expiring/failed certificates

Process Notifications

Processes queued notification events and sends them through configured connectors.

Every 5 minutes

*/5 * * * *

Endpoint: /api/cron/process-notifications

Actions

1Queries queued notification events
2Resolves notification routes for each event
3Sends via Email, Telegram, WhatsApp, or Webhook
4Updates delivery status
5Creates retry entries for failed deliveries

Retry Failed Notifications

Retries failed notification deliveries with exponential backoff.

Every 5 minutes

*/5 * * * *

Endpoint: /api/cron/retries

Actions

1Finds failed notifications eligible for retry
2Checks retry count (max 5 attempts)
3Applies exponential backoff delay
4Attempts redelivery
5Moves to dead letter after max retries

Generate Recurring Obligations

Creates next instances of recurring obligations when current ones are completed.

Daily at 2 AM

0 2 * * *

Endpoint: /api/cron/recurrence

Actions

1Finds completed obligations with recurrence rules
2Calculates next due date based on recurrence type
3Creates new obligation instance
4Copies template configuration
5Assigns to same branch and owner

Vercel Configuration

Cron jobs are configured in vercel.json:

{
  "crons": [
    {
      "path": "/api/cron/ssl-scan",
      "schedule": "0 */12 * * *"
    },
    {
      "path": "/api/cron/process-notifications",
      "schedule": "*/5 * * * *"
    },
    {
      "path": "/api/cron/retries",
      "schedule": "*/5 * * * *"
    },
    {
      "path": "/api/cron/recurrence",
      "schedule": "0 2 * * *"
    }
  ]
}

Monitoring Cron Jobs

Monitor job execution in the Vercel dashboard under your project → Cron Jobs. Check for failed executions and review logs for errors.

Failed jobs are automatically retried based on the schedule, but persistent failures should be investigated promptly.

Self-Hosted Deployment

If not using Vercel, configure cron jobs using your server's scheduler:

# Linux crontab example
# SSL Scan every 12 hours
0 */12 * * * curl -s https://your-domain.com/api/cron/ssl-scan

# Process notifications every 5 minutes
*/5 * * * * curl -s https://your-domain.com/api/cron/process-notifications

# Retry failed every 5 minutes
*/5 * * * * curl -s https://your-domain.com/api/cron/retries

# Generate recurring daily at 2 AM
0 2 * * * curl -s https://your-domain.com/api/cron/recurrence

Security: Consider adding an internal API key check for cron endpoints when self-hosting to prevent unauthorized access.