Call Window

Call Window is a small private utility for anyone who works with people in different timezones. You set your home city once in Settings, then build a list of contact cards. Each card is a person you talk to: their name, the city they are in, and any notes you keep about them. The card always shows two clocks side by side -- their local time and your local time -- and a small 24-hour strip that highlights when they are inside their own working hours, mapped to YOUR clock so you do not need to do math in your head.

THE OVERLAP PLANNER

Across the top of the home screen, above the list of contacts, there is a 24-hour strip that takes every contact you have and shows the hours when ALL of you are inside working hours at once. The green segments are good times to call. Below the strip a single line tells you the longest contiguous overlap window, in your local clock, in plain numbers like 14:00 - 16:00. It is the fastest way to find a slot that works for the whole team.

CONTACT CARDS

Each card shows:

- the contact name and a small country tag

- their current local time, in big amber digital type

- your current local time, side by side, smaller

- the hour delta between them and you, plus or minus

- a 24-hour strip of when they are in working hours, mapped to YOUR clock

- a small marker showing where the current hour falls

- any notes you keep about them

Tap a card to open the contact editor. There you pick a city from a searchable list of around 40 IANA timezones (the major ones for Europe, the Americas, Asia, Africa, Oceania, plus UTC). The body field is for free notes -- agenda points, things to discuss, anything you want to remember about the person before you call.

NEW CALL BUTTON

The action button lives in the top-right corner of the header as a small amber pill labelled + NEW CALL. Tap it and a compose sheet pops up with name and timezone fields. There is no floating button, no bottom dock action, no hidden gesture -- the action is plainly visible on every screen.

SETTINGS

In Settings you pick your Home City from the same searchable list of IANA timezones. You can also toggle between 24-hour and 12-hour clock formats (Europe-friendly default is 24-hour) and tune the working window to something other than 9-17 (7, 8, 9 or 10 to start; 16, 17, 18 or 19 to end).

PRIVACY

Call Window keeps every contact on your device. There is no sign-in, no cloud sync, no analytics, no ad SDK. The contact store is encrypted at rest with a key that lives in the Android Keystore. No network permissions are requested. If you uninstall the app, the contacts go with it.

WHO IT IS FOR

- remote and distributed teams who jump between timezones every day

- founders, designers and engineers running calls with offices in multiple regions

- freelancers juggling clients in Berlin, New York, Tokyo and Sydney

- recruiters scheduling interviews across regions

- anyone with family or close friends in another timezone who never wants to call at 3 AM by accident

NO ACCOUNTS. NO CLOUD. NO ADS. JUST TIMES.