JSONL Chat

Android chat app where conversations are plain JSONL files

A minimal Android chat app where conversations are plain JSONL files in a folder you choose. Anything that can append a line of JSON to a file can talk to you: a script, an AI agent, a cron job, another device through a synced folder (Syncthing, Nextcloud…).

No account, no server, no network permission. Just files.

How it works Each conversation is a .jsonl file (JSON Lines) in your workspace folder — one message object per line:

{"id":"5f1c9a2e-3b7d-4c8f-9e0a-1d2b3c4d5e6f","user":"Alice","message":"Hello!","timestamp":"2026-07-11T14:32:05"} {"id":"7a2d0b3f-4c8e-5d9f-0a1b-2c3d4e5f6a7b","user":"Guest","message":"Hi Alice","timestamp":"2026-07-11T14:33:12"} Field Description id Unique message id (UUID recommended) user Sender display name message Message body timestamp Local date-time, ISO format yyyy-MM-dd'T'HH:mm:ss The app watches the folder and notifies you when a message from someone else appears. To reply from another program, append one line — that's the whole protocol.

Features Scoped folder access (SAF) — you pick the workspace folder once through the system picker Notifications with inline reply — answer directly from the notification shade, full conversation history in the notification Adaptive polling — a foreground service checks the folder for changes (configurable: 1–15 s while the app is open, 5–120 s in the background) and never wakes the device from sleep Instant push — writers on the same device can broadcast com.yighy.jsonlchat.POKE after appending to skip the wait for the next poll tick; can be turned off in Settings Material 3 Expressive UI — dynamic color (Material You), light/dark/system theme, themed monochrome icon, list-detail layout on tablets and foldables Message history cap — optionally keep only the last N messages per conversation (trimming runs lazily, ~20% past the limit, so appends stay cheap)