Jackson Shuttleworth

Group Product Manager at Duolingo, leading the retention team (at time of recording). Formerly a management consultant who flew weekly for ~6 years. Based in Kansas City.

Over four years led 600+ experiments on the Duolingo streak feature, making him the foremost practitioner of streak mechanics in consumer software. Duolingo’s streak is widely cited as the single most impactful feature (beyond the core lessons) in a $14 billion business.

Known for: the zero-to-seven day retention cliff; the unit of measure principle (streak unit must match the fundamental unit of use); the bend-not-break / Serenity Prayer balance between flexibility and perfection; streak sanctity and the one-way door problem; visibility signals value; copy testing culture. Self-described as ‘an amateur armchair psychologist’ on language-learning motivation.

Episodes in this wiki

• Jackson Shuttleworth on Duolingo Streaks, Retention Mechanics, and 600 Experiments — Lenny’s Podcast

Key ideas

• Streak Mechanics — match the streak unit to your unit of use; invest in day 0–7; bend-not-break flexibility; guard streak sanctity (one-way door); visibility signals value.
• Metric-owned teams — own a metric (CURR), not a feature; founder reviews every change to protect sacred spaces.
• Test everything, simplest V1 first — ~one experiment every other day; ship the core hypothesis, then iterate.