# FlagLine Offside Lab — Visual offside geometry skill

> Visual offside geometry skill (iPhone/iPad app by Valentin Postolach.)

- Source: https://appshunter.io/ios/app/flagline-offside-lab/id6802378403 (this page in markdown: same URL + `.md`)
- Developer: [Valentin Postolach](https://appshunter.io/developer/6786063395)
- Category: Education, Sports
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 5 MB
- Languages: American English
- Released: 2026-08-25
- Data updated: 2026-10-03

## What is FlagLine Offside Lab?

FlagLine Offside Lab turns offside from a fuzzy sideline argument into a visual geometry skill you can practice anywhere—no signal, no account, and no dense rulebook on the touchline.

Built for youth assistant-referee trainees, high-school players, parent-coaches, and new center officials who must judge the line under pressure. Place attackers, the second-last defender, teammates, and the ball on a true half-pitch grid. The app draws a live offside line, grades edge cases, and explains the outcome in plain English.

GEOMETRY LAB
Drag and drop up to 11 attackers or defenders plus the ball on a true-scale half-pitch. Snap players to lanes, flip attack direction, and watch the offside line redraw live with distance-to-line readouts and a clear ON, OFF, or WAIT verdict chip.

EDGE-CASE BENCH
Toggle structured ruling cards for interfering with play, interfering with an opponent, gaining an advantage, deliberate play (including deflections), goalkeeper hand or arm involvement, and exemptions on throw-in, corner, and goal kick. Each card shows a mini diagram you can promote into the full lab.

50+ SEEDED FREEZE-FRAMES
Browse scenarios tagged by topic—tight shoulder, late runner, keeper parry, defender header, free-kick wall rebound, goal-kick exit—and by age band from youth through adult. Fork any pack item into your own editable copy.

DECISION MODE
Reveal a frozen pitch without the answer, choose Onside, Offside, Play-on, or Wait-and-see within a soft countdown, then unlock a plain-language rationale, the correct IFAB-aligned principle, and a one-tap restage in Geometry Lab.

SCENARIO EDITOR
Name the frame, place players and ball, attach the intended correct call and a short coach note, save into personal packs, and reorder packs for self-study before a course or match weekend.

RUN-THE-LINE GUIDE
Interactive touchline path showing where an assistant should stand relative to the second-last defender, when to drop and sprint, signal sequence, and large-type rainy-day cue cards for pre-match briefing.

EXPORT, WIDGETS, AND ACCESSIBILITY
Export a printable PDF cue sheet with scenario thumbnails, correct calls, and personal notes via the system share sheet. Pin a Home Screen widget that shows a daily seed scenario prompt plus your last Decision Mode accuracy summary. Dynamic Type, high-contrast pitch themes (light stadium or dark night match), and yards or meters are supported in Settings.

ONBOARDING THAT TEACHES
Walk a short onboarding that teaches the second-last-defender rule with three animated half-pitch demos, then pick your role persona—assistant-ref trainee, player, or parent-coach—to bias default scenario packs.

PRIVACY BY DESIGN
Everything persists in on-device storage. No accounts, no network required, no player contact data, and no analytics resale. A seeded-content reset never wipes user-created packs without confirmation.

Turn offside into a repeatable visual skill—live line math, graded freeze-frames, edge-case rulings, and sideline cue cards that work with zero signal.

## Is FlagLine Offside Lab safe?

Not enough ratings yet to assess FlagLine Offside Lab.

## Is FlagLine Offside Lab legit?

FlagLine Offside Lab has limited verification signals. The AppsHunter Legitimacy Score for FlagLine Offside Lab is 58 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 2 releases)

### 1.2.0 — 2026-08-26

The app now provides faster feedback during user interactions.

### 1.0 — 2026-08-25

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 2026-10-03.*