Second vs Atto

Precise server time, at a glance. Second-Sync is a time synchronization tool for moments where one second matters, such as course registration and ticketing. It multi-samples the HTTP Date of your chosen site and aligns the difference from the server clock down to milliseconds. Drift tracking maintains accuracy over time, while the PiP timer lets you watch live server time even when using other apps. Key features - Precise synchronization: collects HTTP Date in parallel at least 30 times, then calculates the offset after RTT compensation, outlier removal, and EMA smoothing. - Drift estimation: runs linear regression on measured samples to track the slope of the device clock and maintain accuracy as time passes. - PiP timer: opens a Picture in Picture timer as a companion app, so you can monitor the server clock live while using a browser or other apps. - Example site shortcuts: quick buttons to load course registration pages for major Korean universities and ticket booking sites. - Multilingual support: supports Korean, English, Japanese, and Simplified Chinese, with a separate in-app language setting. Recommended for - Anyone who wants exact server time in situations where it is critical, such as registration, ticketing, or reservations. - Anyone who wants to keep accurate server time visible on iPhone or iPad while booking on the go. Notes - Synchronization may fail on sites that do not support the HTTP Date header. If so, enter another target server or use the example sites in the app. - Picture in Picture works only on supported devices running iOS 15 or later, including iPadOS. - Sync your server time with Second-Sync now. One button gives you stable synchronization and a PiP timer, so you do not miss the important moment!

A ticket drop is decided in milliseconds, not seconds. The queue opens on the booking server's clock, not your phone's. The two are usually tens to hundreds of milliseconds apart, and that gap decides your place in line. Atto reads the server's clock directly, and shows you how well it read it. Measuring server time An HTTP Date header only resolves to the second, so one read tells you ±500ms and no more. Atto probes at 137ms intervals so each request lands on a different phase inside the second. Once the offset narrows, it predicts when the server's second will roll over and aims at that edge. Twenty overlapping measurements fold the error down to the round trip. The error bar stays visible Instead of a label like "high accuracy" you get the measured figure: ±23ms. Sample count, rejected samples, best round trip, and how far this server runs from national standard time are all on screen. Cached responses get dropped When a CDN answers instead of the origin, the clock inside that response is frozen at the moment it was stored. Atto checks the Age and cache headers and keeps those responses out of the average. Device drift correction Your phone's oscillator runs seconds off per day. Atto measures the slope between syncs, extrapolates it to now, and re-syncs every two minutes while you wait. Picture in Picture Press Start and a Picture in Picture window floats above your other apps. Show a decreasing countdown or a corrected wall clock that advances toward your configured target, with three-digit milliseconds. Keep the timing in sight while using a booking app or webpage. Haptics and sound Taps begin at the lead time you set and end with one hard hit at zero. The whole pattern goes to Core Haptics up front rather than a timer, so zero does not move even if the screen stutters. Sound is optional and plays through the silent switch. Practice mode A recommended lead time is somebody else's number. Measure the gap between the buzz and your tap actually registering, then apply your own median. Time sources Over 300 sources across 14 regions, including Ticketmaster, AXS, StubHub, Interpark, e+, tixCraft and Damai, plus course registration sites and sneaker drops. Standard-time servers like NIST, NPL, PTB, NICT and KRISS are there too, and you can type any address yourself. Free and paid Everything that decides whether you get the ticket is free: full sync accuracy, drift correction, the on-screen countdown, haptics, every time source, practice mode. One rewarded ad floats a single countdown in a PiP window. A one-time purchase removes ads and keeps PiP unlocked. It is not a subscription. Reading a clock takes one HEAD request. Atto never asks for an account and takes no part in the booking itself. English, 한국어, 日本語