Shared travel notebook

A trip to Japan, day by day, in one notebook for two.

Routes, steps to tick off, luggage, lodging, cards to show at the counter: the notebook opens on the day you are living, stays in step across two phones, and its assistant prepares changes that you approve.

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No account, no personal data: a five-day fictional trip, two phones side by side, wiped after use.

In the notebook

Everything the day needs, in one page

Each tile says where the thing lives in the notebook.

Today firstDaylight, weather, what happens next
RoutesGoogle Maps, Apple Maps or Uber, prefilled
LodgingAirbnb and Booking searches, ranked districts
LuggageWhere the suitcases travel, day by day
Cards to showLarge Japanese text for the counter
MoneySpending, yen to francs, shared totals
AssistantChecks official sites, proposes changes
OfflineThe page and the tickets stay on the phone

Every day

Each morning, the right page

In Live mode the notebook opens on the current day, on Japan time. What is useful now sits at the top of the card; the detail stays folded just below.

Daylight, luggage and weatherSunrise and sunset, where the suitcases are, a real forecast up to 16 days ahead.
NowThe first step not yet ticked, at the head of the card.
Routes of the dayEach leg opens in Google Maps, Apple Maps or Uber, from where you stand.
Steps, photos and placesTick as you go, with “Take me there” from your position.
Full mode when you need moreRoute map, search across the whole plan, bookings, sources.

Screenshot: the card for day 2 of the demo notebook, with sunrise, luggage, the Now block and the routes of the day — The day card in Live mode, on the fictional demo trip. The notebook itself is written in French.

Live

Two phones, one notebook

What one of you ticks, the other sees at once. Every change travels to the server as an operation, then reaches the other phone on a live stream.

Shared — ticked steps and routes, notes, spending, chosen lodging, bookings, packing, preparations and “My details”.
With no network — changes wait in a queue on the phone and leave as soon as the connection returns.
On reconnection — each phone reads back what it missed: nothing is lost, nothing is applied twice.
Kept per phone — the display mode, the preferred maps app, the exchange rate.

Camille ticks a step: the operation goes to the server, which passes it straight on to Sacha’s phone.

Assistant

The assistant proposes, you decide

Ask from either phone. The assistant reads the plan, checks official sites, then prepares a change that you apply, dismiss or undo.

Your key, your provider — Anthropic, OpenAI, DeepSeek or any compatible server. The key is encrypted on the server.
It reads before it writes — with narrow tools (get_day, get_city, search_plan…) and the official pages it reads from the server.
Eleven short playbooks — guide it: check a fact, change a day, lodging, luggage, writing style…
Every proposal is checked — by the change engine: exact location, expected current value, schema and style rules.
Nothing changes without you — each applied change creates a version, and the last hundred stay restorable.

Screenshot: the assistant proposes replacing a step, with the reason, the source and the Apply and Dismiss buttons — A proposal on the fictional demo trip: Apply, Dismiss, or undo it later.

See it for real

See the place before you stand in it

A plan says “autumn colours at the temple”. The notebook also opens what people are showing there right now, so you can judge the light, the crowd and the timing yourself.

Links only. Nothing is copied, stored or re-published here: each button opens the app or the official page, and what you find there stays there.
In preparation for the next release.

Instagram and TikTokWhat visitors posted this week, by place and by hashtag.
YouTubeA walk filmed end to end, to see the route before you take it.
Photos on Google MapsThe entrance, the queue, the counter: what it looks like on the ground.
Official live camerasThe view from the site itself, when the place runs one.
Autumn colour reportsThe 紅葉 status published by the gardens and the tourist offices.

Live demo

Try it with two phones, right here

A five-day fictional trip from Kyoto to Hiroshima, shared between Camille and Sacha. You arrive on day 2: tick a step on one phone, watch it appear on the other, then ask the assistant for a change.

A sandbox of your ownWiped after 20 minutes without activity, with no account and no personal data.
A scripted assistantNo key and no outside call, but the real change engine and real versions.
A live journalEvery ticked box, every answer and every version, with the time it took to arrive.

Open the demo on its own page

Security and privacy

Private by default

The notebook holds tickets, addresses and booking numbers: it is built to keep them safe.

One password, and that is all
Checked against a scrypt hash, with a growing delay after each failure and a session in an HttpOnly cookie.
A locked page
A strict content security policy: only the site’s own scripts run, and inline ones only by hash.
Tickets and keys encrypted
The document vault uses AES-256-GCM; API keys are encrypted too and never travel back to the phone.
Guarded web reads
The assistant only reads public hosts, with the IP address checked and size and time bounded; what it reads stays data, never an instruction.
Hosted in Switzerland
A small server behind an HTTPS proxy, with an encrypted backup every night.
No tracking, no indexing
No analytics, no advertising, and the site is not indexed by search engines.

All the security measures Privacy

Read on

Under the hood

Syncing, assistant, versions, documents, offline and security: every mechanism is explained, with diagrams.

Read how it works