How to Build Realtime Chat Messaging App Using Appscript & Google sheet | B14

A private messaging app where the database is a Google Sheet. Users sign up, find each other, and hold one-to-one conversations that stay readable afterwards — no server, no messaging service, no per-user cost.

Finding someone to talk to

Your contacts are listed with a search over them, which matters once the list runs past a handful. And when the person you want is not in the list at all, you type their username and press Connect — the conversation opens directly. That is how a new user gets talking on their first day instead of waiting to be added by somebody.

Reading a conversation back

Sent messages are green, received are grey, and every message carries its date and time. Those two choices are what make the history usable weeks later: you can tell at a glance who said what and when, rather than scrolling an undifferentiated list. Everything is stored in the sheet and filtered per conversation, so each person sees only the messages that involve them.

Staying signed in

A session lasts three hours. Refreshing the page does not throw you out mid-conversation, but the login does expire rather than staying open indefinitely on a shared machine — a sensible middle ground for a chat app people leave open.

What it does not do

This is the straightforward one: text conversations, contacts and history. There are no attachments, read receipts, presence indicators or push notifications. If you need those, the larger Apps Script chat builds cover ticks and presence, file attachments with message deletion, and connection requests that must be accepted before chatting.