How strides Uses Milestone Emails to Drive User Retention
strides sends personalized goal milestone emails that are timed to exactly when a user hits a streak or completes a habit. Open rates are 61%. Here's how they built it.
strides is a habit tracking and goal-setting app. The core loop is simple: set a goal, track progress daily, build a streak. The product insight that drives retention is that the moments immediately after a user hits a milestone — a 7-day streak, a 30-day streak, a completed goal — are the moments they're most likely to continue. strides uses Sendbound to send a personalized milestone email within seconds of each achievement.
Trigger architecture
Every milestone event in strides emits a webhook to their backend, which calls the Sendbound API with a pre-built template ID and a personalization payload. The payload includes the user's name, the specific goal they hit, the streak count, their longest-ever streak for comparison, and a dynamically generated "next milestone" target. Sendbound renders the template server-side and delivers it — the entire round trip from event to inbox is under two seconds.
"We've tried every retention tactic in the book. The milestone email beats all of them by a wide margin. 61% open rate isn't a typo. It's because it arrives at exactly the right moment."
Personalization at scale
strides tracks dozens of milestone types: daily streaks at 3, 7, 14, 30, 60, 100, 365 days; goal completion; personal records; and "comeback" milestones when a user returns after a lapse. Each has a distinct template. Sendbound's template versioning system lets the strides team A/B test subject lines and body copy without any engineering involvement — the growth team owns the emails end to end.
