Cron jobs from 2003 to today: from web space to AI agents

A cron job starts a task on a schedule. The principle has been the same since the 1970s; what changed is where it runs: in 2003 most websites had no command line, and hosts often offered cron jobs only at night or every 30 minutes. Today almost every platform has its own scheduler, and AI assistants schedule tasks themselves. A timeline with sources, our own numbers and an outlook.

Updated: · by Joscha Schultze, operator of Cronjob.de
Written with AI assistance, all facts with sources.

  1. 1970s to 2002

    The roots: cron on Unix

    Version 7 Unix, at the end of the 1970s, already had a cron that read a single file of schedules[1]. From 1988 Paul Vixie wrote the cron that today's Linux cron is based on: every user gets their own crontab[2]. Anyone with a server and a command line still schedules tasks this way.

  2. 2003

    Web space without a command line

    Most websites lived on cheap web space: FTP and a control panel, but no command line and therefore no crontab. Systems like Drupal made do with a "poor man's cron" that runs along with normal page requests[5]. This is the year Cronjob.de started, back then under a different address.

  3. 2004

    Cronjob.de at today's address

    At one large German host, cron jobs were only available from a certain plan upwards according to its FAQ, set up with crontab -e in the vi editor[4]. Our home page described the problem like this back then: providers often restrict cron jobs so that, for example, they only start once a day at 3 pm[3]. The answer was the same as today: we call the address of your script from outside on a schedule.

  4. 2007

    WordPress introduces WP-Cron

    WordPress 2.1 introduced a "pseudo-cron"[7]. To this day it only runs when someone loads a page[8]; without visitors, scheduled posts and backups wait. At another large host, cron jobs were only available at extra cost in the two cheapest plans[6].

  5. 2009

    Cron jobs at night between 3 and 5 am

    According to its FAQ, a large German host ran simple cron jobs "between 3:00 and 5:00 in the morning", without finer control. The shortest interval was half an hour, and only in bigger packages[9]. For a shop that syncs orders or a newsletter that needs to go out quickly, that was not enough.

  6. 2011

    The cloud gets schedules

    Heroku launched its Scheduler: tasks every 10 minutes, hourly or daily[10]. Its documentation still says openly that execution is "expected but not guaranteed"[11]. Drupal moved the page-request cron into core with version 7[5].

  7. 2012

    Hosts get finer

    The same large host added intervals of 5, 10 and 15 minutes. Before that, 30 minutes had been the shortest[12]. Calls to the minute remained the exception in classic web hosting.

  8. 2016

    Schedules at AWS

    With CloudWatch Events, Amazon Web Services could trigger events on a schedule[13]; the EventBridge Scheduler followed in 2022[23]. Cron moved from the single server into the platform.

  9. 2018

    Google Cloud Scheduler

    Google introduced a "fully managed cron job service"[14]. Anyone working in Google Cloud no longer needs a server of their own for it.

  10. 2019

    GitHub Actions and n8n

    GitHub Actions became generally available[15] and can start workflows on a schedule. GitHub itself says such runs can be delayed under high load, and the shortest interval is 5 minutes[16]. The same year n8n launched, today one of the best-known automation tools with its own schedule trigger[17].

  11. 2020

    Cron at the edge

    Cloudflare launched Cron Triggers for its Workers[18]: code without a server that still runs on a schedule.

  12. 2021

    Kubernetes CronJob becomes stable

    With version 1.21, CronJob in Kubernetes reached general availability[19]. Here too the docs say carefully that a job is created "approximately once" per scheduled time[20].

  13. 2022

    Serverless and CMS catch up

    Netlify launched scheduled functions[21]. Joomla 4.1 got its own task scheduler that also works "if your website host does not allow cron jobs"[22], a familiar problem twenty years after web space without crontab.

  14. 2023

    Vercel Cron Jobs

    Vercel introduced Cron Jobs, available on all plans from November 2023[24]. Since then, projects built with AI tools such as Bolt or v0 can trigger tasks on a schedule as well.

  15. 2024

    Databases and AI connections

    Supabase brought cron, built on pg_cron, directly into the database[26]. Anthropic released the Model Context Protocol, an open standard that lets AI assistants operate other services[25]. Cronjob.de can be managed through it as well.

  16. 2025

    AI assistants schedule things themselves

    Google gave Gemini "scheduled actions": recurring tasks that the assistant carries out itself[27]. Scheduled tasks moved from a developer tool to a feature for everyone.

  17. 2026

    Agents on a schedule

    Claude Code got "Routines": AI agents that start on a schedule, via API or on an event[28]. At Cronjob.de you describe the schedule in one sentence or paste your host's instructions, and an AI assistant creates the cron job. The job itself has not changed: trigger reliably at the right time and notice when something does not run.

What has changed among our users

People who signed up to Cronjob.de in the last two years call far more often than earlier cohorts and much more often address cloud services and automations. The share of cron jobs running at least every 5 minutes around the clock has quadrupled compared with accounts from 2021 to 2023.

Shares of active cron jobs by account sign-up year
Account signed up at least every 5 min, around the clock at most once a day WordPress Cloud and automation
2003–200927%37%1%3%
2010–201520%54%4%4%
2016–202022%51%3%2%
2021–202310%63%1%1%
2024–202641%30%12%16%

How we counted: all cron jobs active today, without heartbeats, grouped by the year the account signed up, as of 25 Oct 2026. "Cloud and automation" means the address belongs to n8n, Make, Zapier, Vercel, Supabase, Netlify, Render and similar services or is an API endpoint (/api/). Older cohorts only include accounts that are still active today. Addresses with an AI connection are below 1% in every cohort; our data does not show an AI boom (yet).

Will there be more cron jobs? Our assessment

We think: yes, but in different places. The classic crontab on your own server is becoming rarer. Instead, almost every platform has a scheduler, and more and more software runs automatically: according to Imperva, more than half of web traffic was automated in 2024 for the first time (51%)[29], and according to Cloudflare, fetches by AI agents on behalf of users rose more than 15-fold in 2025[30]. Both are vendor studies and measure web traffic, not cron jobs.

In favour of more scheduled tasks: serverless functions have no permanent process and need a trigger from outside. According to Datadog, over 70% of its AWS customers used at least one serverless service in 2023[31]. AI agents that write daily reports, sync data or sort inboxes need a schedule too.

What does not change: platform schedulers are often explicitly not guaranteed. GitHub mentions delays under load[16], Heroku "expected but not guaranteed"[11], Kubernetes "approximately once"[20]. The more runs automatically, the more important it becomes whether it really ran. That is why, besides calls from outside, we also offer heartbeats for tasks that run elsewhere.

About Cronjob.de

Joscha Schultze has worked on the web since 1996 and built his first website in 1998. He started Cronjob.de in 2003 for his own projects and with the aim of offering it to everyone, first under a different address and at cronjob.de since 2004. It runs on servers in the EU and is operated from Germany.

Common questions

Since when have cron jobs existed?
The cron service has existed since Version 7 Unix at the end of the 1970s. The form common today, with a crontab per user, goes back to Paul Vixie from 1988. External cron job services like Cronjob.de appeared in the early 2000s for web space without a command line.
Why did you need an external cron job service in the past?
Because web space usually had no command line, and hosts often offered cron jobs only in bigger packages, at extra cost or with coarse timing, such as once a night or at most every 30 minutes. An external service calls the address of a script and only needs a reachable web page.
Do I still need cron jobs if my platform has a scheduler?
You can use the platform's scheduler. Several providers write themselves that their schedules are not guaranteed: GitHub mentions delays under load, Heroku "expected but not guaranteed", WP-Cron only runs on page loads. A call from outside or a heartbeat shows you whether the task really ran.
Will AI agents replace the cron job?
If anything, the opposite: AI products are getting schedules of their own, and agents that are meant to do something regularly need a trigger and a check that they ran. That is our assessment, not a measured fact.

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Sources

  1. Unix V7, cron.c (TUHS): tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/cron.c
  2. Paul Vixie, cron (README, Quellcode): github.com/vixie/cron
  3. Cronjob.de, home page of 13 Feb 2004 (Internet Archive): web.archive.org/web/20040213124641/http://www.cronjob.de:80/
  4. Hosting FAQ on cron jobs, April 2004 (Internet Archive): web.archive.org/web/20040408092803/http://faq.1und1.de:80/hosting/technik/cron/1.html
  5. Drupal, Poormanscron: drupal.org/project/poormanscron
  6. Hosting plan overview, February 2007 (Internet Archive): web.archive.org/web/20070209085535/http://www.all-inkl.com:80/?cna=webhosting&cnb=tarifdetailuebersicht
  7. WordPress 2.1 (Release Notes): wordpress.org/documentation/wordpress-version/version-2-1/
  8. WordPress Plugin Handbook: Cron: developer.wordpress.org/plugins/cron/
  9. Hosting FAQ on cron jobs, February 2009 (Internet Archive): web.archive.org/web/20090204180413/http://www.df.eu:80/austria/service/service-guide/df-faq/technische-faq/cronjobs.html
  10. Heroku: Scheduler add-on (12.11.2011): heroku.com/blog/heroku_scheduler_add_on_now_available/
  11. Heroku Dev Center: Scheduler: devcenter.heroku.com/articles/scheduler
  12. Hosting blog on shorter intervals, January 2012 (Internet Archive): web.archive.org/web/20120201211405/http://www.df.eu:80/blog/tag/profi-cronjobs/
  13. AWS: CloudWatch Events (14.01.2016): aws.amazon.com/about-aws/whats-new/2016/01/introducing-cloudwatch-events-monitor-and-rapidly-react-to-changes-in-your-amazon-web-services-resources
  14. Google Cloud: Cloud Scheduler (07.11.2018): cloud.google.com/blog/products/application-development/announcing-cloud-scheduler-a-modern-managed-cron-service-for-automated-batch-jobs
  15. GitHub: Actions (08.08.2019): github.blog/news-insights/product-news/github-actions-now-supports-ci-cd/
  16. GitHub Docs: Events that trigger workflows: docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows
  17. n8n Docs: Schedule Trigger: docs.n8n.io/integrations/builtin/core-nodes/n8n-nodes-base.scheduletrigger/
  18. Cloudflare: Cron Triggers (28.09.2020): blog.cloudflare.com/introducing-cron-triggers-for-cloudflare-workers/
  19. Kubernetes 1.21: CronJob GA (09.04.2021): kubernetes.io/blog/2021/04/09/kubernetes-release-1.21-cronjob-ga/
  20. Kubernetes Docs: CronJob: kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/
  21. Netlify: Scheduled Functions (2022): netlify.com/blog/quirrel-joins-netlify-and-scheduled-functions-launches-in-beta
  22. Joomla 4.1 (15.02.2022): joomla.org/announcements/release-news/joomla-4-1-0-stable-new-standards-in-accessible-website-design.html
  23. AWS: EventBridge Scheduler (10.11.2022): aws.amazon.com/about-aws/whats-new/2022/11/amazon-eventbridge-launches-new-scheduler/
  24. Vercel: Cron Jobs (22.02.2023, GA 15.11.2023): vercel.com/changelog/vercel-cron-jobs-are-now-generally-available
  25. Anthropic: Model Context Protocol (25.11.2024): anthropic.com/news/model-context-protocol
  26. Supabase Cron (04.12.2024): supabase.com/blog/supabase-cron
  27. Google: Scheduled actions in Gemini (06.06.2025): blog.google/products/gemini/scheduled-actions-gemini-app/
  28. Claude Code: Routines (14.04.2026): claude.com/blog/introducing-routines-in-claude-code
  29. Imperva Bad Bot Report 2025 (vendor study): imperva.com/blog/2025-imperva-bad-bot-report-how-ai-is-supercharging-the-bot-threat/
  30. Cloudflare Radar 2025 Year in Review (vendor study): blog.cloudflare.com/radar-2025-year-in-review/
  31. Datadog serverless report 2023 (vendor study): datadoghq.com/about/latest-news/press-releases/datadog-report-finds-the-serverless-ecosystem-growing-across-all-major-clouds/

Details about hosts describe the state of the respective archive copy, not today's.