Offline planner apps for iPhone: what still works with no signal

Who wrote this: Kalend is our own app and it is the first of the 9 entries below. We list it first deliberately, because it is what we would use, and you should read it with that in mind. It is judged on the same fields as everything else and carries its own stated drawbacks, including that it is iPhone only and still in development rather than on the App Store. There are no affiliate links on this page.

Kalend is our own app and it is listed first here, which is worth saying plainly before you read anything else. The ordering is not a verdict on quality; it is our product, in our list, at the top. Every other entry is a competitor, and each one is described only from what its own App Store listing or its own documentation states.

The test applied to all nine is the same. Can you open the app cold, on a plane or in a basement, and see your day? Can you create and edit — a task, an event, a habit tick, a journal line — without waiting on a spinner? Does any part of the interface block on a server round trip, such as a login check or a shared list? And when the connection returns, does it reconcile the changes sensibly instead of handing you a pile of duplicates?

Where an app publishes a clear statement about offline use, that statement is quoted below. Where it does not — and several of the apps here do not — that is said rather than guessed. A missing statement is not proof that an app fails underground; it means nobody has committed to the behaviour in writing, which is a different sort of risk to carry onto a long flight.

At a glance

The apps in detail

What is still missing

The first thing this category gets wrong is silence. Search the help centre of a well-known planner for the word offline and you will often find nothing at all — no statement, no article, no line in the App Store description. Four of the nine apps here commit in writing — Kalend included — and they do it in a sentence each; a fifth, Calendars by Readdle, commits only for dragging an item to a new time. The rest leave you to discover the answer at 30,000 feet, which is the worst possible place to find out that a list will not load.

The second problem is that offline is treated as a degraded mode rather than the ordinary one. Features that genuinely need other people — a shared list, an assigned task, an invitation — sit in the same menus as features that need nothing but the phone, with no marking to tell them apart. Assistant features that draft or reschedule a day make this sharper, because they are increasingly the headline of a paid tier and none of the listings here says whether that work happens on the phone or somewhere else. An app can be honest about all of this and simply label which buttons require a connection. None of the nine listings surveyed here does.

Kalend, ours, works offline-first and syncs through your own iCloud, so there is no account of ours to reach and nothing to log into when the signal drops. That design has a real price attached. There is no sharing and no collaboration of any kind — you cannot assign a task or share a list with a partner or a colleague — it is iPhone only, with no Android, web, iPad-optimised or Mac version, and it is in App Store review rather than released, so you cannot install it today. A household that plans together is not served by it, and being offline-first does not fix that.

Common questions

Which of these planners state in writing that they work with no connection?

Four of the nine. Cultured Code says Things devices store your full database locally so you can work offline. Pocket Informant's App Store listing says an internet connection is only required for syncing. Omni's sync FAQ says a sync connection is not required in order to use OmniFocus, and each device holds a full copy of the database. Kalend, our app, is offline-first, with every feature working with no connection. Calendars by Readdle commits for one thing only — rescheduling by drag and drop, which it says works both online and offline. For the rest, nothing is published either way on the pages cited here.

What is the difference between offline-first and just cached?

A cached app shows you what it downloaded last time and often refuses to write until it can reach a server. An offline-first app keeps the real database on the phone, treats the server as a copy, and writes locally whether or not there is signal. The practical test is whether you can create something new — not just read — with the connection off. Reading a stale list is not the same as planning your day.

What happens if I edit the same task on two devices with no signal?

That is a sync conflict, and the answer depends entirely on the app's reconciliation logic. Cultured Code states it directly, saying conflicts resolve automatically with logic inspired by version control systems. Omni describes a database held as a list of changes that the server compares at the next sync. Most apps in this list say nothing at all, and in that case the safe habit is to open the app on one device, let it finish syncing, and only then open the second.

Does a habit streak still count if I tick it off with no connection?

It depends on whether the tick is recorded on the phone or sent to a server. If the app writes locally with a timestamp, the tick belongs to the day you made it and the streak survives the flight. If the app only counts a completion the server has acknowledged, a day underground can read as a miss. None of the listings surveyed here spells this out for its habit tracker, so if the streak matters to you, test it once in aeroplane mode before you rely on it.

Do I need an account to use a planner offline?

Needing an account and working offline are separate questions that get confused often. Kalend has no account of ours at all, because it syncs through your own iCloud, and Omni's documentation says a sync connection is not required to use OmniFocus, so sync can be left off entirely. An account only matters offline if the app checks the login before it will let you in — and none of the listings cited here states whether it does.