Custom Client-Specific Information in Outlook Add-In Manifest File: Reading and Storing Values During Side-Loading

Question

Hi Team,

 

We are working with Outlook add-ins and have encountered a situation where we need some guidance:

 

To summarise – we want to know if there is a possibility to put some custom information in the Outlook Add-In’s manifest file and have the Outlook Add-In read/fetch that custom information from the manifest file while users side-load (install) the Add-In using this manifest file. Please note that this manifest file is not the one which is packaged along with the release/build folder which we deploy on a web-server. Instead, this manifest file is the copy which we hand-over to our users for side-loading the Add-In.

 

Here is a detailed explanation of the situation --

 

1. We have deployed/hosted our Outlook Add-In on a Microsoft Azure Storage Account.
2. We have two clients, Client A and Client B, to which we want to distribute this Outlook add-in.
3. For distribution, we would be handing over a copy of the manifest file, to both Client A and Client B, with which they will side-load the add-in. Let’s call the copy of the manifest file for Client-A as Manifest_Client_A. and the copy of the manifest file for Client-B as Manifest_Client_B.
4. Please note that the side-loading will be performed by the respective Administrators of both Client A and Client B i.e. by Microsoft 365 Admin Center.
5. Please also note that we are not publishing our Outlook Add-In on the Microsoft Store (which is achieved through Microsoft Partner Portal Program. Get started with Integrated apps - Microsoft 365 admin | Microsoft Learn
6. Now, there is also this requirement where we want to keep some custom information in both the manifest files, different for each client, i.e. in Manifest_Client_A  & Manifest_Client_B.
7. We need to share specific, client-tailored information, particularly regarding OAuth 2.0 (such as Application ID, Tenant ID, and Scope registered in the Microsoft Azure portal) which varies from one client to another.
8. Although the template for this information is the same for both clients, the values differ.
9. For instance, consider:
   1. For Client A, the manifest file Manifest_Client_A will contain

<APPID> App id client A </APPID>

<TenantID> Tenant id client A </TenantID>

<Scope>Scope client A</Scope>

1. For Client B, the manifest file Manifest_Client_B will contain

<APPID> App id client B </APPID>

<TenantID> Tenant id client B </TenantID>

<Scope>Scope client B</Scope>

 

1. Now, while Client-A Administrator side-load the add-in (for the entire organization via Microsoft 365 Admin Center) from their manifest file Manifest_Client_A, we want our Add-In to read the values of APPID, TenantID & Scope (the values being “App id client A”, “Tenant id client A” & “Scope client A”) from this manifest file and cache/store it somewhere. So that, after the side-loading, when any user of the organization (Client-A) opens/runs this Add-In in their Outlook, the Add-In should have access to the values for APPID, TenantID & Scope for Client-A (the values being “App id client A”, “Tenant id client A” & “Scope client A”), which was saved in their manifest file Manifest_Client_A.
2. And, similarly, for Client-B.
3. We want to know if there is a way to achieve this.

Your insights on achieving this would be greatly appreciated!

 

Thanks