Flip Timer vs Sumi
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Flip Timer
This app uses your phone's proximity sensor to minimize distractions by activating a timer when placed face down. It helps you concentrate on tasks and reminds you to take breaks. Strict mode prevents early interruptions.
- Proximity sensor activation
- Blocks notifications and apps
- Strict mode for discipline
- Flashlight notification
- Customizable timer length
Read full descriptionHide full description
Flip Timer utilizes your phone's proximity sensor to help you stay focused on your work. It activates when your phone is placed face down on a table, eliminating distractions from notifications or tempting apps, allowing you to concentrate fully on your current task. Once the time is up, the timer will ring to remind you to take a break or transition to your next task. – If strict mode is enabled, the timer will reset if you flip your phone back before the time is up. Discipline is key! – Flashlight feature helps you notice when the timer ends, especially useful in quiet environments. – Customizable timer length: use it for work or rest.
Sumi
This app helps you reduce phone usage by setting timers for breaks. It alerts you if you touch or move your device during the break, aiming to boost productivity and mental well-being.
- Timed phone breaks
- Movement alerts
- Productivity enhancement
- Mental health improvement
- Simple interface
Read full descriptionHide full description
The most beautiful thing an app can do is get out of your way. Sumi sits quietly on cream paper, holds your attention for an hour, and asks for nothing back. Set a length. Put your phone face down. Pick it up before the time is done and the session breaks — not as a punishment, but as a commitment kept. No ads. No notifications. No streaks-as-slot-machines. No weekly subscription trap. Just deep work, and the quiet record of the hours you've given it. — THE RITUAL — Set an intention and a length. Put the phone down. Sumi keeps watch: lift it, or leave the app, and the session ends. When the time is held, the line completes, your lifetime hours grow, and the session is logged. Silent while you work. Quietly rewarding when you finish. — A CALM LEDGER, NOT A GAME — The number that only goes up: your lifetime hours focused. A streak, if you want one. A week that fills, a line that climbs. No characters to feed, no points, no dark patterns. Progress you can feel, with nothing engineered to hook you. — MADE FOR DEEP-WORK PEOPLE — For writers, developers, designers, students of a craft — anyone who already romanticizes focus and resents apps built to fracture it. Graphite and cream. Monospace. Paper grain. A single calligraphic mark. — PAY ONCE — Your focus shouldn't be a recurring charge. Sumi is free to use, with an optional one-time Lifetime unlock (or a subscription, if you prefer) for custom lengths, full history and trends, themes, and session intentions. Put the phone down. Pick the work up. ——— Privacy Policy: https://dayonefoundry.com/sumi/privacy Terms of Use (EULA): https://dayonefoundry.com/sumi/terms
Screenshots
Verdict
The clearest difference is review sentiment: Flip Timer at 100% against Sumi's 0%. Flip Timer also leads on rating (5.0 vs 3.0) and in-app purchases (none vs 3). On price, ratings volume, update cadence and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Sumi sells 3 in-app purchases, starting at $5.99 per month. Flip Timer asks for nothing beyond the download.
Flip Timer holds the better App Store score, 5.0 against 3.0. Both are backed by a comparable volume of ratings — 2 and 2 respectively. Written reviews point the same way: 100% of Flip Timer's written reviews are positive against 0% of Sumi's.
Flip Timer ships an update weekly, Sumi every 5 days. The most recent releases landed on August 12, 2026 and September 20, 2026 respectively.
| Parameter | Flip Timer | Sumi |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) — better | 3.0 (2 ratings) |
| Positive reviews | 100.0% of reviews — better | 0.0% of reviews |
| Number of ratings | 2 | 2 |
| Update frequency | Weekly | Every 5 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | Free |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 16.1 | 16.0 — better |
| Further details — not scored | ||
| Size | 4 MB | 10 MB |
| Age rating | 4+ | 4+ |
| Developer | Daniil Kim | David Park |
Customer experience
Flip Timer
Sumi
In-app purchases
Flip Timer
No in-app purchases
Sumi
- Sumi Pro Monthly$5.991 Month
- Sumi Pro Annual7 Days trial$24.991 Year
- Sumi Pro Lifetime$49.99









