Sign in to Microsoft with your own app

The Microsoft calendar, with your own Microsoft app source reads your Outlook or Microsoft 365 calendar, from a personal account or a work or school one, after you sign in to Microsoft. Maisnie has no Microsoft app of its own, so the sign-in goes through one you register yourself, for free, in Microsoft Entra (Microsoft’s site for app sign-ins). It takes about ten minutes, once. This page walks through it screen by screen. The words in bold are the words Microsoft’s own pages show.

What the app can do is decided at sign-in: Maisnie asks Microsoft to read your calendars and to keep that access, so it can go on reading without asking you to sign in again every hour. It never asks to change your calendar, and it never asks for your mail.

Before you start

Turn on Microsoft calendar, with your own Microsoft app on the Sources step, then open the Accounts step. The card says “You need your own Microsoft app first.” and has one field, Application (client) ID. Keep that page open: the steps below end with one value to copy into it.

If you have a personal Microsoft account (an outlook.com, hotmail.com or live.com address, or any address you made a Microsoft account with), do this first, because Entra does not let a personal account in on its own. Signing in to entra.microsoft.com with one fails with:

Selected user account does not exist in tenant ‘Microsoft Services’ and cannot access the application ‘74658136-14ec-4630-ad9b-26e160ff0fc6’ in that tenant. The account needs to be added as an external user in the tenant first.

That is not a mistake on your side. A personal account has no directory (Microsoft calls it a tenant) of its own, and an app has to be registered inside one. A free Azure account makes the directory for you:

Go to azure.microsoft.com/free and press Try Azure for free. Sign in with the same personal Microsoft account.
Fill in the sign-up form. Microsoft asks for a phone number and a payment card to prove you are a person. The free account does not charge the card, and Maisnie never uses anything Azure charges for.
When it finishes, open portal.azure.com. Your account now has a directory called Default Directory.
Use the portal for the steps below: in its search box type App registrations and open it. (After step 3, entra.microsoft.com also lets you in.)

If you have a work or school account, open the Microsoft Entra admin center at entra.microsoft.com and sign in. Any account with a directory works for making the app; it does not have to be the one whose calendar you will read. If your work account will not let you register apps, ask your administrator, or use a personal account as above.

This route has not yet been repeated by the project from a brand new personal account, so if a screen differs from this page, the goal is the same: a Microsoft account that has a directory.

1. Register the app

Open App registrations (in Entra under Applications, in the Azure portal by searching for it) and press New registration.
Give it any Name you will recognise later, for example “Maisnie at home”.
Under Supported account types, choose the option that starts Accounts in any organizational directory and ends and personal Microsoft accounts. That one lets the same app sign in to a personal Outlook account and to a work or school account.
Leave the rest as it is and press Register.

2. Say it is an app on your own computer

In your new app, open Authentication and press Add a platform.
Choose Mobile and desktop applications.
Under Custom redirect URIs, add http://localhost and press Configure.
Back on Authentication, under the new platform, press Add URI and add http://127.0.0.1 as well.
Further down, under Advanced settings, set Allow public client flows to Yes.
Press Save.

These two addresses are where Microsoft sends you back to at the end of the sign-in: the computer Maisnie runs on.

3. Allow it to read your calendar

Open API permissions and press Add a permission.
Choose Microsoft Graph, then Delegated permissions.
Search for Calendars.Read, tick it, and press Add permissions.

Calendars.Read reads your calendars and nothing else. You do not need to add any other permission: Maisnie asks for the rest of what it needs (to sign you in and keep its access) when you sign in.

4. Copy the Application (client) ID

Open Overview and copy the Application (client) ID, a long value of letters, numbers and dashes.

There is no secret to make. An app on your own computer cannot keep one hidden, so Microsoft does not use one for it, and the card has no field for one. Skip Certificates & secrets.

On the Accounts step, paste the Application (client) ID into the Microsoft card.
Press Sign in with Microsoft.
Microsoft asks you to choose the account whose calendar you want, then shows Permissions requested: reading your calendars, and keeping access to what you allowed. Press Accept.
You come back to the Accounts step, and the card says “Connected as” and your address.

If you opened Maisnie from another device (your phone or another computer, not the computer Maisnie runs on), the last page of the sign-in does not load; the card explains what to copy and where to paste it.

From then on your Microsoft meetings arrive as notes on the calendar’s usual schedule.

Microsoft Teams chats

The Microsoft Teams source reads your Teams chats with the same kind of app, and it keeps its own sign-in, so it never touches the calendar’s. Use the same app registration if you like: in step 3, also add the delegated permission Chat.Read, which reads your chats and nothing else (it cannot send, edit or delete). Then turn on Microsoft Teams on the Sources step and do step 5 on its card.

Teams chats need a work or school account that uses Teams. A personal Microsoft account has no Teams chats this way, and many work tenants only allow apps their administrator has approved: if the card says an administrator may need to approve the app, ask yours to grant consent for Chat.Read, then sign in again.

Signing out

Press Sign out on the Microsoft card. Maisnie forgets the sign-in on this computer; notes already in your vault stay where they are.

Microsoft offers no way for an app to hand its own access back, so signing out here does not reach Microsoft. To remove the app’s access completely, also remove the app from your account: at account.microsoft.com for a personal account (under privacy, the apps and services that can reach your data), or at myaccount.microsoft.com for a work or school account (under Apps, or the permissions you have given). The card on the Accounts step says the same.

If it does not work

Microsoft says you need an admin’s approval. Some work and school accounts only allow apps their administrator has approved. Ask your administrator to approve the app (they will see it by its name), or use a personal account.
The card says “This Microsoft account has no calendar that can be read this way.” The account has no mailbox: a work or school account needs a mailbox with Microsoft 365 for its calendar to be readable. Sign in with an account that has one.
The card says “This Microsoft account did not allow reading the calendar.” The app is missing Calendars.Read, or you declined it. Do step 3, then press Sign in with Microsoft again.
The sign-in fails straight away. The Application (client) ID is not the one Entra showed. Copy it again from Overview. Check that Allow public client flows is on and that both addresses from step 2 are there.
Entra or the Azure portal says “Selected user account does not exist in tenant ‘Microsoft Services’”. You signed in with a personal Microsoft account that has no directory yet. Follow “If you have a personal Microsoft account” under Before you start, then try again.
Azure sign-up will not accept your card or phone. A prepaid or virtual card is often refused. Try a regular debit or credit card, or ask a colleague with a work account to register the app (the app can read your calendar even though they made it).

Back to connect your accounts, or the same steps for Google.