# Acid Interval: Focus Timer — Pomodoro timer for deep work

> Visually distinct Pomodoro and focus timer for deep work sessions. (iPhone/iPad app by Preston Carr.)

- Source: https://appshunter.io/ios/app/acid-interval-focus-timer/id6815378728 (this page in markdown: same URL + `.md`)
- Developer: [Preston Carr](https://appshunter.io/developer/6815378730)
- Category: Productivity, Health & Fitness
- Price: Free with in-app purchases
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English
- Released: 2026-09-29
- Data updated: 2026-10-05
- Monetization: freemium

## What is Acid Interval?

A focus timer worth looking at.

Most focus timers look like a spreadsheet with a countdown in it. This one is built the other way round.

A single enormous numeral, bleeding off the edge of a field of acid green. Behind it, a mechanism that moves once per second, locked to the clock and never drifting. Rings that bounce, breathe, ripple inward, or pass momentum down a Newton's cradle. When you start a session the whole field inverts to black and the numbers light up like something switched on behind them.

Tap anywhere to start. Swipe to change the mechanism. Double-tap to change the colour. You never have to open a menu.

25/5, 50/10, 90/20, or count up. The classic pomodoro, longer ultradian blocks, or open-ended flow when you don't want a deadline.

Timed properly. Built on timestamps, not ticks. Lock your phone, switch apps, come back: it is exactly where it should be.

It tells you when you are done, even with the screen off.

No account. No sync. No data leaves your phone.

ACID INTERVAL PRO
One payment unlocks all eight mechanisms, all seven colourways, and custom interval lengths. The timer itself is free and always will be.

## Key features

- Unique visual interface
- Customizable timer intervals
- Engaging animation mechanisms
- Screen-off notifications
- No account or data sync
- Phone lock compatibility

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Acid Interval Pro | $2.99 | one-time |


## Is Acid Interval safe?

Not enough ratings yet to assess Acid Interval.

## Is Acid Interval legit?

Acid Interval: Focus Timer has limited verification signals. The AppsHunter Legitimacy Score for Acid Interval is 58 out of 100 points across 7 verification signals from App Store and developer data.


## Frequently asked questions about Acid Interval

### What is Acid Interval?

Acid Interval is a focus timer designed for deep work, featuring a unique visual interface and customizable intervals. It aims to provide a more engaging and less conventional experience than typical countdown timers.

### Does Acid Interval have ads?

No, Acid Interval does not contain advertisements. The core timer functionality is free, and users can unlock additional features through a one-time purchase.

### What are the timer options in Acid Interval?

Acid Interval offers classic Pomodoro (25/5), longer ultradian blocks (50/10, 90/20), and an open-ended flow mode for users who prefer no set deadlines.

### Can Acid Interval notify me when a session is done with the screen off?

Yes, Acid Interval is built to provide notifications even when the screen is off, ensuring you are alerted when your focus session is complete.

### What makes Acid Interval's interface different?

Instead of a spreadsheet-like display, Acid Interval features a large, prominent numeral with dynamic, animated backgrounds that react to the timer. Users can change these visual mechanisms and colors with simple gestures.

### Is there a paid version of Acid Interval?

Yes, Acid Interval Pro is available as a one-time purchase. This unlocks all eight visual mechanisms, seven color themes, and the ability to set custom interval lengths.

### Does Acid Interval collect user data?

No, Acid Interval emphasizes privacy. It requires no account, no syncing, and no data leaves your phone, ensuring a secure and private user experience.

### How often is Acid Interval updated?

Acid Interval was last updated on September 29, 2026, with version 1.0. As a new release, future updates will likely focus on refining features and potentially adding new content based on user feedback.

## Version history (last 1 release)

### 1.0 — 2026-09-29

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-05.*