Sumi is a minimalist productivity app for iOS that tracks deep work sessions via a face-down timer mechanism.
The App DNA
What makes this app unique?
Users hire Sumi to enforce focus through a low-friction, non-gamified ledger that rewards commitment without the distraction of streaks or notifications.
For Writers, developers, designers, and students who prioritize focus and prefer minimalist, non-gamified productivity tools.
What does it look like?
Key features
Records total lifetime hours focused when the phone remains face down and the app stays active.
Ends the session if the user lifts the phone or leaves the app before the timer completes.
Allows users to define specific work durations beyond default settings.
How much does it cost?
Freemium model uses a one-time purchase or subscription to gate advanced customization and historical data.
Velocity
Maintenance developmentUX improvementsShow more...
Sumi: Deep Work Focus ships approximately 0.17 releases per week, placing it in the maintenance tier. The development trend is stable but limited to minor refinements rather than significant feature expansion. The latest release focused on small wording adjustments and session pacing, with no evidence of new content or live operations. Development activity remains minimal as of the most recent update on June 27, 2026.
Who built it?
David Park
4 apps tracked · Productivity
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Dog Friendly: Walks & PlacesUser Sentiment
What do users think recently?
Review voice lately leans mixed. Users appreciate the core concept of the session timer provides a compelling hook for users seeking focus.
How are ratings & reviews evolving?
What users say, by theme
- The core concept of the session timer provides a compelling hook for users seeking focus
- Active session timers terminate prematurely when the screen is open or the app is active
1 of 1 recent reviews analyzed · limited sample
Read the full review analysisCompetition
Competitive landscape for Sumi: Deep Work Focus
How's the Productivity market?
Sumi occupies a niche minimalist segment in the Productivity category, holding a 3.0-star rating on the iOS platform. The lack of recent feature updates suggests a maintenance-mode posture that limits its ability to compete with high-velocity rivals.
Read the market outlookThe rivals identified
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Access the full report for freeThe Analyst's Read
Key takeaways for Sumi: Deep Work Focus
Where is it heading?
The minimalist productivity market is consolidating around tools that offer reliable background tracking, leaving Sumi exposed. Without resolving the session-termination defect, the app will struggle to retain users beyond the initial download, regardless of its aesthetic appeal.
- The timer fails to maintain state during active use, which directly undermines the app's core value proposition and drives negative sentiment.
The SWOT
- Minimalist design language functions as a brand barrier against gamified productivity rivals
- Education partnerships offer a B2B distribution channel for non-gamified focus tools
Next best moves
Rebuild session-tracking logic because timer termination during active use is the top complaint → reduce churn
The counter-intuitive read
The minimalist design is a liability rather than…
Read the full takeBottom line
Sumi offers a compelling, non-gamified focus tool, but the timer defect breaks the core experience, so the PM must prioritize stability over feature expansion to prevent immediate user churn.
Unlock 2 critical frictions, 1 market threat and the analyst’s take.
Access the full report for freeSources
- [1] App Store, source
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