Atto reads the booking server's own clock — not your phone's — and then shows you what other timers hide: how accurate that measurement actually was.
Download on the App StoreiPhone · iOS 17 or later · Free · Ad-supported · One-time purchase to remove ads
"Accuracy: high" tells you nothing. Atto computes an error bar on every sync and puts it on screen together with what produced it.
One response only narrows the offset to a second-wide window. But that is a hard constraint, and measuring at another phase of the second constrains a different edge. Atto sweeps the phase in 137 ms steps, then predicts the instant the server's second ticks over and aims straight at that edge.
When a CDN answers for the origin, the time inside froze at the moment it was stored. Atto reads the Age and cache-status headers and drops those samples instead of mixing them into the average, because reading a stopped clock and calling it a sync is the worst mistake this app could make.
An oscillator off by a few ppm blunts even a perfect sync within the hour. Atto fits the slope between syncs by weighted least squares, extends it to the present, and tells you how many seconds a day your device drifts.
Start in Picture in Picture (PiP) and the countdown floats in a small window over other apps and the browser.
It shows the time remaining, or a clock of the corrected server time running up to your target, down to three digits of milliseconds. You can wait for 0 without taking your eyes off the booking page.
From the second you choose it vibrates once a second, then once hard at 0. For sound you can also pick a telephone-style time signal: pip, pip, pip, beep. The whole pattern goes to Core Haptics up front, so the 0 does not move even if the screen stutters.
Set 09:00, 10:00, 12:00 or 18:00 with one tap; the opening time shows with its date and weekday, like "Wed, Oct 1". Practice mode measures your own reaction time.
No app on iOS can stop another app's notifications or switch on Do Not Disturb. Atto says so plainly, then does the three things that actually work.
Atto exposes an “Arm countdown” action. Pair it with “Set Focus” in a time automation and the phone goes quiet and arms the countdown without you touching it.
With your permission Atto reads only whether a Focus is on — not which one. If nothing is silencing the phone while the countdown is armed, it warns you.
The strongest option, and entirely yours to turn on: enable Accessibility › Guided Access, then triple-click the side button on the purchase page. Banners and calls are blocked and app switching is locked.
The usual approach in this category, and the choice Atto makes.
| Aspect | Usual approach | Atto |
|---|---|---|
| Accuracy | Low / medium / high, higher tiers locked | Always maximum, with the measured ±ms on screen |
| Method | Repeated sampling, averaged | Interval intersection + second-edge aiming + SNTP cross-check |
| Cached responses | Used without distinction | Rejected via Age and cache-status headers |
| Device drift | “Please sync again” | Measured in ppm and corrected up to the present |
| Display | Floating window, each size paywalled separately | PiP over other apps — one rewarded ad per countdown, or a one-time purchase |
| Zero alert | A vibration on the second | Pre-scheduled Core Haptics ladder, no jitter |
| Lead compensation | A fixed recommended value per site | Your own reaction time, measured in practice mode |
| Price | Ads, plus paid tiers to remove them | Free. Accuracy and the countdown are never locked; one purchase removes ads for good |
In the list by country, yours comes first. Search, favourites and custom URLs are supported, over both NTP and HTTP.
Your country's ticket sites, bundled — for example Ticketmaster, AXS, Live Nation, SeatGeek, Eventim, DICE and more
Nike SNKRS, adidas, Supreme, StockX, GOAT, POP MART and more
NTP servers such as NIST, NPL, PTB and NICT. Over 300 sites across 14 regions are supported, including e+, tixCraft and Interpark.
One response only constrains the offset to a window one second plus the round trip wide. But that window is a hard constraint, and probes taken at different phases of the second constrain different edges of it. Atto sweeps the phase in 137 ms steps to intersect fourteen windows, then, once the offset has narrowed, predicts the instant the server's second ticks over and aims straight at that edge. The error folds down to roughly the round-trip time.
The queue opens by the time that server thinks it is. Measured in practice, it is not unusual for a site's clock to run tens to hundreds of milliseconds ahead of or behind national standard time. Atto counts down against the site's clock, measures standard time at the same time, and shows the difference between the two on screen.
No. A phone's crystal oscillator is off by a few ppm, so the offset drifts as time passes. Atto estimates the slope between syncs by weighted least squares, shows it in ppm, extrapolates the correction to the present, and re-syncs automatically every two minutes while armed.
Time signals and standard time are accurate, but what decides when a sale opens is the booking site's server clock. If that clock is off from standard time, the 0 is off even when you set yourself by the time signal. Atto measures both the site's clock and standard time, and shows the difference between them too.
Yes. The major ticket sites of your country come bundled, so you pick your country from the list and sync. A site that is not on the list syncs too once you enter its URL.
Yes. Start it in Picture in Picture (PiP) and the time remaining, or the server-time clock, floats in a small window over other apps and the browser, down to three digits of milliseconds. You can wait with the booking page open.
No app on iOS can block another app's notifications, and Atto does not pretend to. Instead it warns you when nothing is silencing the phone, and exposes an Arm countdown action to Shortcuts so a time automation can switch on Do Not Disturb and arm the countdown. Turn on Guided Access in Accessibility yourself and notifications are blocked outright.
No. It only sends a single HEAD request to read the time. It never asks for your account details and takes no part in the purchase.