How to Set Up Cron Jobs with Azure Functions (Timer Trigger)

Azure Functions Timer Triggers run your function on a schedule defined by an NCRONTAB expression. NCRONTAB is a 6-field cron format that includes seconds, similar to Quartz cron.

Timer Triggers are serverless — you don't manage any infrastructure. Azure handles scaling, retries, and execution. You only pay for execution time.

Create a Timer Trigger function:

func new --name TimerTask --template "Timer trigger"

JavaScript/TypeScript example:

// src/functions/timerTask.ts
import { app, InvocationContext, Timer } from '@azure/functions';

app.timer('timerTask', {
  schedule: '0 */5 * * * *',  // Every 5 minutes
  handler: async (timer: Timer, context: InvocationContext) => {
    context.log('Timer function ran at', new Date().toISOString());

    if (timer.isPastDue) {
      context.log('Timer is past due!');
    }

    await processQueue();
  },
});

C# example:

[Function("TimerTask")]
public void Run(
    [TimerTrigger("0 */5 * * * *")] TimerInfo timer,
    FunctionContext context)
{
    context.Logger.LogInformation($"Timer ran at: {DateTime.Now}");
    if (timer.IsPastDue) context.Logger.LogWarning("Timer is past due!");
}

Azure uses NCRONTAB — a 6-field format with seconds:

second minute hour day-of-month month day-of-week

Examples:

• 0 */5 * * * * — Every 5 minutes
• 0 0 * * * * — Every hour
• 0 0 9 * * 1-5 — Weekdays at 9 AM
• 0 0 0 1 * * — First day of every month
• 0 30 9 * * * — Daily at 9:30 AM

The first field is seconds. If you only provide 5 fields, Azure treats it as standard cron (no seconds).

• 0 */5 * * * * — Every 5 minutes
• 0 0 * * * * — Every hour
• 0 0 0 * * * — Daily at midnight
• 0 0 9 * * 1-5 — Weekdays at 9 AM
• 0 0 0 1 * * — First day of every month
• 0 0 */6 * * * — Every 6 hours
• 0 0 12 * * * — Every day at noon

Run locally with Azure Functions Core Tools:

npm install -g azure-functions-core-tools@4
func start

Timer triggers run on schedule even locally. To test immediately, send a POST to the admin endpoint:

curl -X POST http://localhost:7071/admin/functions/timerTask -H "Content-Type: application/json" -d '{}'

Timezone configuration in host.json:

{
  "extensions": {
    "timers": {
      "defaultTimezone": "Eastern Standard Time"
    }
  }
}

Uses Windows timezone names. On Linux consumption plan, use IANA names like America/New_York.

Azure Functions integrates with Application Insights for monitoring:

• Invocation count — verify your timer is firing
• Duration — track execution time
• Failures — alert on errors

app.timer('timerTask', {
  schedule: '0 */5 * * * *',
  handler: async (timer, context) => {
    const start = Date.now();
    try {
      await processQueue();
      context.log(`Completed in ${Date.now() - start}ms`);
    } catch (error) {
      context.error('Timer task failed:', error);
      throw error; // Rethrow so Azure marks it as failed
    }
  },
});

Set up alerts in Azure Monitor for function failures or high duration.

Handle past-due timers: When your function app scales from zero, timers that were missed during the cold start will fire with isPastDue = true. Decide whether to process or skip them.

Singleton lock: By default, timer triggers use a blob lease to ensure only one instance runs at a time across all scaled instances. This is handled automatically.

App Settings: Store the schedule in an app setting for easy changes:

app.timer('timerTask', {
  schedule: '%TimerSchedule%',  // Reads from app settings
  handler: async (timer, context) => { ... },
});

Then set TimerSchedule = 0 */5 * * * * in your Function App's Configuration.