/00/Case study / 2023 · Independent publisher

Otter
Studio

A reading app that remembers why you paused.

// role
Mobile design
Swift + Kotlin engineering
Sync architecture
// stack
Swift UIJetpack ComposeCRDT syncRails API
// duration
9 months
// team
4 GreenCoders
Otter Reader
On "The Overstory" — ch. 14
pages
342
streak
28d
pauses
14
/01/Summary

Otter Studio publishes long-form non-fiction. Their audience reads slowly, over months. The app had to honour that.

+34%
sessions/wk
+22%
finish rate
4.9★
App Store
2.8k
reviews
/02/
Challenge

Existing reading apps optimise for streak anxiety and completion percentages. Otter readers complained the apps made them read *less*. The publisher wanted an app that respected the pause.

/03/
Approach

We built a gesture-based bookmarking system inspired by 18th-century marginalia. Pauses are first-class — the app asks you why you paused and later surfaces those notes when you return. No streaks. No badges. No progress bars.

/04/
Outcome

Average reading session dropped 8% (intentional). Sessions per week up 34%. Books finished rate up 22%. App Store rating 4.9 with 2,800 reviews. Two Swift community awards.

/05/ Across devices

Same system. Every surface.

Margin Notes
Why you paused here
notes
214
returned
62%
Library
14 titles · 6 in progress
finished
8
paused
6
/06/Process

Four seasons, in order.

/01/ Seed

Diary studies with 9 Otter subscribers. 'Why I paused' became the core insight.

/02/ Sprout

Paper prototype tested in an actual park. Gesture set refined over 6 rounds.

/03/ Canopy

Shipped iOS and Android in parallel. CRDT sync let a pause on iPhone appear on iPad.

/04/ Harvest

Launched quietly. Readers wrote love letters. We kept the first 30 taped to the studio wall.

/07/Details

Moments that earn a pause.

Listen
Audio · ch. 14 · 18:42
speed
1.0x
left
42m
Otter Reader
On "The Overstory" — ch. 14
pages
342
streak
28d
/08/Full composition

One system, three frames.

greencode://work/margin-notes
Margin Notes
Why you paused here
notes
214
returned
62%
Margin Notes
Why you paused here
notes
214
returned
62%
Margin Notes
Why you paused here
notes
214
returned
62%
/09/ In their words
"The GreenCode team read every book in our catalog before designing the app. It shows on every screen."
Imogen Byrd · Founder, Otter Studio