DELTA.

DELTA is a local-first, encrypted diary and habit tracker shipped as one Go binary. One command runs the API and an embedded dark, monospace web shell on localhost — and on your local network once you turn that on. The diary is a single encrypted file that lives wherever you point it. Its key is generated on your machine and shown once, and a snapshot is taken every day without any setup.

Everything starts at the pixel grid: a year per row, a day per pixel, coloured by your rating or your habit score. Click any pixel to open that day, including empty past days you want to backfill. Hold a key and the same grid shows something else — the phases you marked, the eras and dynasties you have named, or how much you wrote each day — and full-text search finds any entry from the same screen.

Closing a day is a short wizard — freeform prose, yesterday’s goals, three gratitudes, the three Ws, four 1–5 ratings, hours worked, habits — and saving rolls straight into tomorrow’s five goals. Habits carry validity ranges, so pausing or retiring one never rewrites the past. Over time Stats turns the entries into streaks, completion rates, and monthly trends, each set against the year before. The same diary can be scripted through a CLI and a REST API.