Offline notes should be boring: you capture on a plane, in a tunnel, in a field with one bar of signal, and the note is simply there — written, searchable, filed — with sync happening later only where you chose it. Thoughts is built offline-first on iPhone, with on-device intelligence doing its work without a connection. This guide explains exactly what works with no signal, what waits, and how to set up sync so “offline” and “private” reinforce each other instead of getting confused.
What “offline-first” actually means
Many apps treat the phone as a window onto a server: no connection, no notes, or a read-only cache with a spinner where your library should be. Offline-first inverts that. The library lives on the device; the cloud, where you enable it, is a sync and sharing layer on top. Capture, editing, search and browsing are local operations that never ask permission from a network.
The practical test is aeroplane mode. Turn it on and try the full loop in Thoughts: capture by voice, read the tidied thought, give it a title, file it in a project, search for it by a word it contains, open an old project and reread something from last month. All of that is device work, and all of it should succeed at 35,000 feet.
On-device AI is why offline still feels smart
Cloud-AI apps go quiet offline because their intelligence lives elsewhere. In Thoughts, the built-in help — tidying a spoken capture, suggesting a title, matching a thought to a likely project — runs with local models. Availability depends on your device and the feature, and a model may need downloading before a trip, so check the app's intelligence settings while you still have Wi-Fi. Do that once and the “smart” parts of capture travel with you. The distinction between local processing and cloud features is unpacked in private AI notes on iPhone: what stays on your device.
What waits for a connection
Three things, all of them about other people or other services rather than your notes themselves. Sync of projects you chose to sync happens when a connection returns. Shared-project changes from collaborators arrive then too — which means activity an AI assistant reports is ordered by when the server received it, so an offline capture can appear in “recent” lists on the day it syncs, not the day you spoke it. And the ChatGPT/Claude connector is inherently online: an assistant can only read or save thoughts that have synced, so last night's tunnel capture is invisible to it until you surface. None of this blocks you; it simply queues.
Sync by choice, per project
Offline-first pairs naturally with deliberate sync. In Thoughts a project is local until you turn sync on for it. That gives you three practical tiers to set up before you need them:
- Always local: journal, sensitive personal notes. Never synced, never reachable by an assistant, works everywhere.
- Synced for you: reference, recipes, plans you want backed up and available to AI help you have approved.
- Synced and shared: household or work projects with collaborators, where offline edits reconcile when everyone reconnects.
Decide at project level, in advance, instead of wondering per-note on a train. Organising notes by project covers choosing and naming those projects so the split stays obvious.
The honest caveats
Local means the device matters
A local-only project has no cloud copy. Before replacing or resetting a phone, check how those notes are backed up or exported, and do not assume a project is synced because others are. Offline-first protects you from dead zones, not from losing the phone itself.
Shared work can diverge briefly
Two people editing the same project while both offline will sync when they reconnect; until then each sees their own latest. For notes this is rarely a problem — thoughts are mostly append-only — but agree ownership of fast-moving shared lists, as in the grocery list workflow.
AI assistants see the synced past, not the local present
Ask Claude about a thought you captured offline an hour ago and it will not find it until sync catches up. If an answer feels stale, open Thoughts, let sync finish, and ask again. Asking AI about your notes covers this and other retrieval checks.
A pre-trip checklist
- Open Thoughts on Wi-Fi and confirm sync is finished for projects you want backed up.
- Check intelligence settings so any on-device features you rely on are ready offline.
- Capture a test voice note in aeroplane mode and find it again by search.
- Glance at which projects are local-only, and be sure that is still your intention for each.
Do that once and “offline” stops being a mode you manage. It is just where some of your best thoughts happen to occur — which, as any brain dump practitioner knows, is rather the point.
Frequently asked questions
Do offline notes work without any signal in Thoughts?
Yes. Capture by voice or text, editing, search, filing and browsing all work on the device. Built-in tidying, titling and project suggestions use on-device intelligence, though a model may need downloading first and availability depends on your device.
What does not work offline?
Sync itself, receiving collaborators' changes, and anything involving a connected AI assistant, which can only read or save thoughts that have already synced. Those catch up automatically when a connection returns.
Is offline the same as private?
Not automatically. In Thoughts you choose sync per project: local-only projects never leave the device, while synced projects upload when a connection is available. Decide project by project, and remember local-only notes need your own backup plan before changing phones.
Why can't Claude see a note I captured an hour ago?
If you captured it offline, it has not synced yet, and assistants can only reach synced content. Open Thoughts with a connection, let sync finish, then ask again.