# Trials
Trials are useful when you want to give your customers some time to try your product before you start charging them. Be it 7 or 30 days, or 6 months, you decide how and when to charge them.
The duration of a trial is defined in the API request in the trial_days
key. For example, a request to create a subscription with a 30-day trial would contain the following in the request body:
{
"trial_days": 30
}
Read more about declaring trial periods in a sample scenario of creating a subscription with a trial or in APIref: Plans.
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