A free-tier user who's just hit a usage limit is at the exact moment they're most likely to upgrade — and the email telling them so should make acting on it as easy as possible. A Countdown adds real urgency to a time-limited discount, and a Product block turns "upgrade now" into an actual Stripe charge, not a link to a pricing page.
The gap between "I should upgrade" and actually doing it is where most PLG upgrade intent quietly dies. Every extra step in that gap costs conversions.
Ground it in real usage
A bar chart or gauge block visualizing how close the account is to its plan limit makes the ask concrete — this isn't a generic "consider upgrading" email, it's tied to something the recipient can see is actually true about their own account.
Add urgency only if it's real
A Countdown to a genuine limited-time discount deadline is a real animated GIF, regenerated on every open — accurate whenever the email is actually opened, not a static line that goes stale.
Complete the upgrade in one tap
A Product block priced at the plan upgrade opens a real Stripe Checkout session on your own connected account directly from the email — no separate pricing-page visit to re-decide on.
Getting the trigger data in
There's no built-in usage-limit detection — usage data needs to flow from your product into a MailInApp data source (an API-connected source or periodic export), with a recurring send's audience filter re-evaluating it on each run to catch accounts crossing the threshold.
Getting started
Export usage data into a data source, add a bar chart or gauge showing how close an account is to its limit, an optional Countdown for a time-limited discount, and a Product block for the upgrade itself. Target the send at accounts crossing the threshold via an audience filter.