Jan Čislinský

Jan Čislinský

Founder of Zvednout to? — the top-rated Czech call-blocking app. Side project since 2016, full-time since May 2026.

Zvednout to? app icon

Zvednout to?

The #1 Czech caller ID app

More at zvednoutto.cz — Zvednout to? caller ID app

Download on the
App Store

Background

In mobile engineering since 2014. Spent 2019–2026 at JLL, growing from Lead iOS Engineer to Senior Manager, Software Engineering, and scaling mobile teams across continents. Earlier: Lead iOS at Etnetera, iOS Developer at Letsgood.com. VŠE graduate.

Press

Kvůli aplikaci na neznámá čísla vstával v pět ráno. Pak dal v práci výpověď a staví z ní velký byznys

CzechCrunch — Ondřej Holzman

Aug 2026

Projects

Zvednout to?

2016 – present

Caller ID, call blocking, and AI call screening in Czech, for iOS.

BetPivot

2019

Basketball bets recommendation app. Shut down — business model didn't pan out.

Siever

2017–2018

SMS scam filter. Never gained traction.

Vivio

2015

Safari ad blocker. Sold my stake to my co-founder.