Guide

Behavioral triggers: a complete guide

How to design behavioral triggers for a free trial: the three kinds, the six fields to write down, how to find events and how to measure them.

By Meralume Labs. Published . 8 min read

A behavioral trigger is a rule that sends a message or changes the product when a person does, or fails to do, something specific. A sound trigger names its event, its condition, one action, a limit on repeats and the moment it stops, and it is judged by paid customers against a group that did not receive it.

What a behavioral trigger is

Most trial messages are scheduled by the calendar: day one, day four, day seven. A behavioral trigger is scheduled by the person. It waits for an event, such as finishing sign-up, importing data or inviting a teammate, or for the absence of an event by a deadline, and then does one thing. The difference sounds small. In practice it separates a message that arrives when it helps from one that arrives when it annoys.

Triggers are not a product by themselves. They are the plumbing that lets a trial respond to what a person is actually doing, and they are only as good as the events underneath. That is why the first section of any trigger project is about events, not copy.

Three kinds of trigger

KindFires onExampleWhere the event comes from
ActionSomething the person didCreated a first project, so offer a short guide to sharing itYour own product events
AbsenceSomething not done by a deadlineNo teammate invited by day four, so explain why trials with teammates go furtherA scheduled check on your own events
BillingA change in the subscriptionThe trial is about to end, or a payment failedPayment provider events

Billing triggers are the most reliable because the provider sends them for you. Stripe documents a customer.subscription.trial_will_end event that fires before a trial ends, and suggests using it to send the customer a message, with a link to your site, when no payment method is on file (Stripe, free trial periods). Action and absence triggers rely on events you define yourself, so they need more care.

The anatomy of one trigger

Write every trigger on one line before building it. If you cannot fill in all six fields, it is not ready.

FieldWhat it holdsExample
EventThe thing that starts the clockTrial started
ConditionWhat must still be true when it firesBilling account not yet connected after 24 hours
ActionOne message or one product changeEmail naming the single next step, with a link straight to it
Frequency capHow often it may fire for a personOnce per trial
Stop conditionWhat cancels itBilling account connected, or trial ended, or person replied
MeasureThe number it must movePaid customers per 100 trials against a holdout

The stop condition is the field teams forget. A reminder that arrives after the person did the thing teaches them to ignore the next one, and a stack of triggers that never cancel each other produces the notification storm every founder has complained about as a user.

Finding the events that deserve a trigger

The ChartMogul conversion report poses a question every trial owner should answer first: at what point does a user actually experience the aha moment, immediately or only after real setup work? Triggers should point people toward that moment. To find it, compare the people who paid with the people who did not and list the actions they took in the first days.

Example numbers, made up for illustration: a seller starts 500 trials and 75 pay, a rate of 15.0% at $59.00 a month. Splitting the cohort by two early actions gives this picture.

Early actionPeople who did itPaidRatePeople who did notPaidRate
Connected their billing account3506618.9%15096.0%
Invited a teammate1504530.0%350308.6%

Both actions line up with higher conversion, and that is a lead, not a conclusion. People who connect a billing account may simply be the people who were already serious. The difference is, though, an upper bound on what a trigger could win. Suppose a nudge got half of the 150 people who never connected to do so, and suppose they then paid like those who connected unaided. That would be about 9.6 extra paying customers on this cohort. The real number will be lower, and a holdout test is the only way to learn how much.

A catalogue of triggers to start with

TriggerFires whenActionStops when
First step stallNo first step 24 hours after sign-upOne email naming the step, with a direct linkStep completed
Setup gapFirst step done, key setup step missing on day 3In-product prompt on next loginSetup step completed
Teammate gapNo teammate invited by day 4Short email on what a second person unlocksTeammate invited
Return after silenceNo login for 3 daysEmail recapping what is already set upNext login
Pre-charge reminderProvider signals the trial is about to endEmail with date, amount and cancel linkTrial ended or person cancelled
Failed paymentProvider reports a failed chargeEmail with a link to update the cardPayment succeeded
Exit questionPerson cancels during trialOne optional free-text questionAnswered or ignored

Psychology, used with care

Two ideas from behavioral economics show up in trigger design, and both are easy to misuse. The first is loss aversion. Wikipedia defines it as a cognitive bias in which the same situation is perceived as worse when framed as a loss rather than a gain, and notes that empirically losses tend to be treated as if they were about twice as large as an equivalent gain. For a trial, the honest application is to be specific about what the person has built and what happens to it when the trial ends: their saved setup, their imported records, their invited teammates.

The second is the default effect. Wikipedia describes it as the tendency to accept the default option, and says experiments and observational studies show that making an option the default increases the likelihood that it is chosen. For a trial, the honest application is to make the plan the person tried the plan they continue on, to show that plan and its price on every reminder, and to make cancelling as easy as continuing. A default that depends on people not noticing is not a nudge; it is a trap, and it produces refund requests and disputes.

Neither idea licenses invented scarcity, countdown timers that reset or claims about how many other people are looking at the same plan. Those are not behavioral science. They are false statements, and a trial built on a card needs the buyer's trust more than most products do.

Timing, priority and frequency

  • Billing messages outrank everything. If a pre-charge reminder and a feature nudge are due the same day, send only the reminder.
  • One message per person per day across all triggers, with a priority order written down.
  • Send in the recipient's own time zone when you know it, and avoid the middle of the night.
  • Give every trigger a frequency cap and a global cap per trial. Five unopened messages are a signal to stop.
  • Prefer an in-product prompt to an email when the person is already logged in. It is faster and costs a person nothing.

Measuring a trigger

Hold back a random share of eligible people from each trigger and compare paid customers, not clicks. Be realistic about sample size. In the example above, 150 people never connected a billing account, and 9 of them paid, which is 6.0%. A rate measured on 150 people has a standard error of roughly 1.9 points, so a difference of a couple of points between a trigger group and a holdout of that size tells you very little. You need either more people or a bigger effect, which is one more reason to start with the stalls that affect the most trials.

Run each test across whole trial cycles, record the result whether it wins or loses and stop a trigger that shows no gain after a fair run. A trigger that survives is a small permanent improvement. One that does not is noise you removed.

Mistakes to avoid

  • Building triggers on events nobody has checked are tracked correctly. Verify each event with a test account first.
  • Triggers with no stop condition, so messages arrive after the action is done.
  • Treating a correlation in the cohort table as proof that the action causes payment.
  • Writing urgency the product cannot back up, such as a deadline that moves.
  • Letting marketing and billing triggers fire independently, with no shared cap.
  • Counting clicks as success. A click is not a customer.

For the number that all of this is meant to move, see the glossary entry for trial to paid conversion rate, and for the schedule that most of these triggers feed into, read the trial email sequence templates. To size a gain before you build, use the trial conversion rate calculator.

What is the difference between a trigger and a scheduled email?

A scheduled email goes out on a date after sign-up whatever the person did. A trigger waits for an event or for the absence of one, and checks a condition before it sends.

How many triggers should a trial have?

Start with three: a stall on the first step, the pre-charge reminder and the failed payment message. Add more only when you can show a stall that affects many trials and a clear action that addresses it.

Is loss aversion a good reason to add scarcity?

No. Loss framing is honest when it describes real things the person has built and will lose access to. It is not honest when it invents deadlines, counters or limited seats.

How do I prove a trigger works?

Keep a random holdout of eligible people who receive nothing, run for whole trial cycles and compare paid customers per 100 trials. Small groups give noisy answers, so expect to need a sizeable effect.

Which events should I track first?

The first useful action, the main setup step, an invited teammate, the last login and the billing events from your payment provider. Verify each one before building anything on it.

Can triggers run from my payment provider alone?

The billing ones can. Stripe sends events such as the trial about to end. Action and absence triggers need your own product events.

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