Atrium
Guide

How Atrium works.

Everything you need to get set up and find your way around — pillars, blocks, the dashboard, the built-in chat, and how the on-device encryption actually protects you. Short version: nothing leaves your device except your own chat messages to your own Claude key.

See what every block does →

01 · Getting started

The first time you open Atrium, you'll be asked to set a passphrase — this is what encrypts everything you log from that point on. There's no account, no email, no sign-up.

1

Set your passphrase

At least 8 characters, entered twice to confirm. It never leaves your device.

2

Read the one-time notice

Atrium spells it out plainly: there's no account recovery. Forget your passphrase and your data can't be recovered.

3

Add your first pillar

Pick a preset or start from Custom — see below.

Coming back later, you'll see a Welcome back screen — enter your passphrase and tap Unlock.

There's no "forgot passphrase" flow. No reset link, no recovery email — that's the trade-off for nobody but you ever holding the key. If you'd rather not rely purely on a typed passphrase, add a passkey (Touch ID, Face ID, or a security key) from Settings → Security once you're in; your passphrase still always works as the fallback.

02 · Pillars

A pillar is one of your "little worlds" — Health, Mind, Money, Business, or anything else you want a dedicated space for. Add one by tapping "+ Add" at the end of the pillar tab strip.

Presets

  • Custom — a blank pillar, built entirely from the blocks you add.
  • Health, Mind, Money, Business, Habit, Wishlist — each starts empty too (no forced starter blocks) but comes pre-coloured and pre-iconed for what it's for; you pick which blocks to add from there.

Tapping a preset creates the pillar immediately — no extra form. Rename it, change its icon, or recolour it afterward.

You can have more than one of the same kind

A second Money pillar (say, "Business Money" next to your personal one) or a second Wishlist ("Shopping List" next to "Christmas") is fully independent — its own tab, its own data.

Reorder pillars by long-pressing and dragging a tab in the footer strip, or from Settings → Design → Pillar order if you'd rather use up/down buttons.

03 · Blocks

Blocks are what actually live inside a pillar — a note log, a budget, a wishlist, a habit tracker. Every pillar's tab strip ends in a "+" tab; tap it to see what's addable to that pillar. Most blocks are available everywhere; a couple (Health Connect, Harvest) are specific to one pillar type.

Some blocks are singletons — once added, they drop off the "+Add" list (Budget, Wishlist, Projects). Others are multi-instance — you can add as many as you like, each independently named (Time Tracker, Day Tracker, Idea Journal, Journal, Moods).

Read the full block-by-block guide → for exactly what each one does.

04 · Editing & deleting

While inside a pillar, the header's ⋯ menu offers "Edit pillar" always, and "Edit <block name>" whenever a block or section tab is open. Both share the same panel:

  • Name — free text.
  • Icon — a picker grid of glyphs and emoji.
  • Border colour — a full colour picker (drag a saturation/value square + hue slider, or type a hex code), plus quick swatches from Atrium's own palette.
  • Nothing commits until you tap Save.

Deleting is deliberately harder to do by accident: you type the pillar or block's exact name into a confirmation box before the Delete button will do anything. Deleting a pillar removes everything inside it; deleting a block removes everything logged in it. Neither can be undone.

Health Connect and Harvest are the two exceptions — since there's nothing to rename (they're a fixed sync, not user content), they have no Edit panel; remove them by deleting the whole pillar.

05 · Reminders

Day Tracker, Journal, and Moods sections can each nudge you if you haven't logged anything yet today. Turn it on from that section's "Edit <name>" panel — a Daily reminder toggle plus a time (8pm by default).

Once that time passes with nothing logged, it shows as a strip above your Front Dashboard's widgets, with a Log now link straight into the pillar and a Not now to dismiss it for the rest of the day.

Purely in-app — there's no OS push notification and no background service. It only checks while Atrium is actually open, matching Atrium's local-only, nothing-runs-on-a-server design.

06 · Dashboard

The Front Dashboard is opt-in — nothing appears there automatically, even a brand-new block. Curate it from the account menu → Edit dashboard:

  • Tap "+ Add widget" to pick from every block/section across all your pillars that isn't already pinned.
  • Each pinned widget gets a small × to unpin it while you're in edit mode.
  • Tap Done to go back to a clean, read-only board.

Plain Notes blocks can't be pinned — only the specialised blocks (Budget, Day Tracker, Wishlist, and so on) have a dashboard widget.

08 · Settings

Reached from the account menu. Four tabs:

AI Connectors

  • Paste your own Anthropic API key — it's encrypted with your passphrase and goes straight from your browser to Anthropic; nothing passes through a server of ours.
  • Pick a chat model: Claude Haiku 4.5 (fastest, the default), Claude Sonnet 5 (balanced), or Claude Opus 4.8 (most capable).

Security

  • Add or remove a passkey (Touch ID, Face ID, or a security key) as a second way to unlock. Requires a device that supports the WebAuthn PRF extension — if yours doesn't, Atrium tells you plainly and you just keep using your passphrase.

Design

  • Background colour (or a two-colour gradient, or your own photo, resized on-device before it's stored), panel style (glass or a solid colour), date format, time format, and pillar order.

Feedback

  • A subject/message box that opens a pre-addressed email to the developer — no backend, so nothing is collected in-app.

09 · Chat

A pinned chat button sits bottom-right no matter where you are in the app. Once you've added an API key, ask it things like "How has my mood been this week?" or "Summarise everything I've logged."

  • Replies stream in as they're generated.
  • It can see everything you've logged across every pillar — but nothing else. It won't invent facts, and it's kept plainly non-clinical: no diagnoses, no medical/financial advice framed as professional guidance.
  • Tap Clear to wipe the visible conversation — chat history isn't saved anywhere; it's gone on reload either way.
Same rule as everywhere else in Atrium: your questions and your data go directly from your browser to Anthropic using your own key. The developer never sees either.

10 · Security & privacy

This is the part Atrium is actually built around, so it's worth stating plainly rather than burying it in fine print:

  • Client-only. No backend, no developer database. There is nothing for anyone else to breach, subpoena, or sell.
  • Encrypted at rest. Every pillar, block, and entry — and your Claude API key — is encrypted before it ever touches your device's storage.
  • Your passphrase is the key. An optional passkey can unlock the same data, but the passphrase is always the fallback and always works.
  • No recovery. Lose every unlock method and the data is gone by design — nobody, including us, can get it back for you.
  • Your own API key, direct to Anthropic. Chat calls go straight from your browser to Anthropic's API. We never see your key, your prompts, or your data.
One honest caveat: a PWA's client-side code can be inspected by anyone determined enough — that's true of any web app, not just Atrium. And health/financial data carries real regulatory obligations in some places even when it's stored purely on-device. If either of those matters a lot to your situation, that's worth knowing going in.

11 · On Android

Atrium's Android build wraps the same app as a native shell — everything's bundled into the install itself, so it runs fully offline with nothing hosted anywhere.

  • The hardware back button navigates in-app history, same as a browser back button — until you're back at the Dashboard, where it exits the app.
  • Passkey unlock may not work reliably inside the Android app's system browser view — your passphrase is the dependable path there.
  • The Android vault is local to that phone only — it's a separate install from any browser copy of Atrium, with no sync between them (by design — see Security above).