Frequently Asked Questions (FAQ)

How much is the service of cron-job.org?

Our service is entirely free of charge.

Is my user data safe with you?

Our promise: We do not share user data with third parties, neither your email address nor your name nor other information. Your password will be stored in our database using state-of-the-art encryption/hashing mechanisms.

What is the minimum execution interval for cronjobs?

Every cronjob can be executed up to 60 times an hour, i.e. every minute.

How many cronjobs can I create?

We do not limit the number of cronjobs per account, but we expect fair usage of our services. We reserve the right to delete accounts which use our service for abusive or excessive purposes.

Which IP address is used to visit my URLs?

At the moment, all requests made by cron-job.org originate from the following IP addresses:

116.203.134.67
116.203.129.16
23.88.105.37
128.140.8.200

Please note that this might change as we expand our service. You can also find the list of current IP addresses in machine-readable form at https://api.cron-job.org/executor-nodes.json.

How and how long does cron-job.org visit my URLs?

cron-job.org visits your URLs at the configured dates/intervals and waits for the URL/script to finish execution. If your URL/script does not finish after 30 seconds, it will timeout and we will close the connection to prevent delays in the execution of the jobs of other users. Our system reads up to 64 KB of the output of your URLs/scripts. In case your script sends more data, job execution will be aborted. (Please also see the next question.)

What should I keep in mind when developing my cron-controlled scripts?

You should design your scripts in a way that they send as little data as possible, ideally just a short status message at the end of the execution, e.g. "OK" — or simply nothing. In case your script is written in PHP and needs more than 30 seconds of run-time, you can use the following trick to let it continue to execute in the background: Use the PHP function ignore_user_abort(true) to tell PHP to continue the script execution after disconnection.

Can I use cron-job.org to fetch SSL/HTTPS protected URLs?

Yes, cron-job.org supports execution of SSL-protected cronjobs. We do not check certificates and thus you can also use self-signed certificates.

Can I use cron-job.org to fetch URLs protected by HTTP authentication (e.g. using .htaccess)?

Yes, just enter the login username and password when creating your cronjob and we will use it to authenticate against your website.

Can I specify custom headers for my cronjobs?

Yes, our service supports arbitrary custom headers. You can specify headers when editing your cronjob. Please note that the headers "User-Agent" and "Connection" are not supported and will be ignored.

Can I send cookies along with my cronjob request?

Yes — just edit your cronjob and add a custom header with the name "Cookie" and the value "name=value", where "name" is the name of the cookie and "value" is its value. You can separate multiple cookies with a semicolon (e.g. "name=value, name2=value2").

Can I use cron-job.org to send POST/PUT/HEAD/... requests?

Yes, we support almost all HTTP request methods specified in the standard. For methods like POST and PUT you can also specify a request body.

Can I view the response/output of my URLs/scripts?

Yes, for every cronjob you can view the last 50 executions with detail information like scheduled date, execution date and response headers/body. We store response headers and bodies for 2 days.

How punctual/accurate is cron-job.org in terms of execution dates?

We use a custom, highly optimized software to execute your jobs. The software is capable of running thousands of jobs in parallel and optimizes the average delay of jobs using a sophisticated algorithm. This way we can keep delays at a minimum. Nevertheless, there may be slight delays during peak hours, i.e. we cannot give a promise or a guarantee on punctuality. Please note that delays often have reasons which are beyond our influence, e.g. slow or overloaded DNS servers, overloaded networks/routers or webservers.
In some rare cases, we might delay your job on purpose to maintain the general stability of the service, e.g. when your job failed lots of times in the past or took very long to execute.

Why does cron-job.org execute my job a few seconds before the scheduled date?

The execution time displayed in the members area shows the date we began to execute your job. We might start to execute your jobs a few moments before the scheduled date because the service needs to perform a few steps before it can actually submit the request to your website, e.g. to resolve the website's hostname. This way we aim to optimize the punctuality of the actual execution.

My cronjob has been deactivated automatically. Why?

In some cases we disable your cronjob automatically, e.g. when it subsequently fails more than 25 times (which is a strong indicator for an invalid/expired URL). You can enable an email notification for this event if you like.

Can I use cron-job.org to monitor my servers?

We offer an email notification feature in case of failed cronjobs. This way you can also use our service to monitor your servers. Just create a job which fetches a small file on your website and enable the failure email notification and we will send you an email as soon as we could not reach your server. We can also send you an email as soon as we were able to reach your server again.

I can see visits of cron-job.org in my webserver logs, but I never signed up for your service.

In case a user of our service set up a cronjob which calls your website without your permission, please contact us using our Report abuse form.