Ask most merchants how long a free trial should run, and their answers will vary widely. Some folks oppose trials, others debate trial lengths from a few days to 30 days, regardless of what they sell.

However, Shopify’s subscription APIs can make this variability really difficult to handle: Shopify “selling plans” (the billing interval, like “1 month”) have a way to transition from a $0 (trial) to the paid interval, but no way to change the length of the free interval.

So previously, Zendra offered only free trial lengths equal to your billing plan: a monthly billing cycle got a 1 month trial; a 2-week billing cycle got a 2-week free trial. The trial length was never really a decision, it was a rounding error inherited from the invoice schedule.

But a trial and a billing interval are answering two completely different questions. One is about how long it takes someone to decide your membership is worth paying for. The other is about how often you want to collect a payment. Treating them as the same setting is why merchants on longer billing intervals so often skip trials altogether, or offer one so long it defeats the point of trying before buying.

Trial length is now its own setting

As of July 9, Zendra sets free-trial length independently of billing interval. Instead of expressing a trial in billing “cycles”, you now enter trial length as a plain number of days on its own field in the plan editor. The two settings no longer have to agree.

That unlocks combinations the old model simply couldn’t express. A weekly plan can now offer a 30-day trial if that’s what the product needs. An annual plan can offer a 7-day trial instead of being stuck at a full year. Trial length and billing cadence are two levers, and you can finally set each one to what it’s actually for.

Why two levers beat one

A free trial works, in part, because it sets a deadline. Ran Kivetz, Oleg Urminsky, and Yuhuang Zheng documented the goal-gradient effect in a 2006 Journal of Marketing Research study: effort and motivation intensify as a goal gets closer, not before. A trial’s end date functions the same way — the closer it gets, the more it nudges someone who’s been putting off a decision to actually make it. Dan Ariely and Klaus Wertenbroch found something related with self-imposed deadlines in a 2002 study: a firm end date changes behavior in a way an open-ended one doesn’t.

That means trial length is really a question about how much runway someone needs before the approaching deadline is doing useful work: long enough to reach the moment your membership feels valuable enough to pay, short enough that the deadline still feels close. Billing interval is a different question entirely — how often you want to collect a payment and how much commitment you’re asking for. There’s no reason the answer to one should determine the answer to the other.

A trial’s length is about the deadline a customer needs. A billing interval is about the cash flow you need. They were never the same decision.

Conflating the two used to force a tradeoff on merchants with longer billing intervals: either skip trials on your annual plan, or give away a full year of access for free just to offer one at all. Neither option is close to what a merchant actually wants, which is a trial short enough to protect the business and long enough to let someone genuinely decide.

Match trial length to what you’re testing

With the two settings separated, the useful question becomes: how long does it actually take someone to reach the part of your membership that makes them want to stay? You should consider a few things:

• Perks a member feels immediately — a member discount or free shipping — can support a short trial, since the value shows up on the first order.
• Content or product access on a drip — perks released over the first weeks of membership — need a trial long enough to reach at least one meaningful unlock, or the trial ends before the member has anything to evaluate.
• Community or ongoing perks tend to need more time before someone feels the pull of belonging, independent of how often you happen to bill.

None of that has anything to do with whether you bill weekly, monthly, or annually — which is exactly the point.

How to set it in the plan editor

Open a plan’s billing option in the Zendra plan editor and enter the trial length as a number of days — that’s it! The field no longer asks you to think in cycles, and it doesn’t care what billing interval sits next to it.

Free trials are available starting on the Starter plan and up, alongside signup fees. And if you already use Shopify Flow to react to trial activity, the Membership Trial Started and Membership Trial Expired triggers fire exactly the same way they always have — you’re changing the number of days, not the automation built on top of it.

For the full setup walkthrough, see Recurring billing & subscriptions in the docs.

Billing interval and trial length were always two different decisions wearing one setting. Now that they’re separate, the useful habit is to tune each one to what it’s actually for: bill on the schedule your business needs, and give the trial the number of days a real decision actually takes.