Customer service in Microsoft Teams: how business clients can message you straight from Teams
Your business clients spend all day in Teams and would rather write to you there than by email. Here are the routes Microsoft offers for chats between companies, what IT on both sides has to allow, and how those chats become one shared inbox.
Deskwoot Team
8 min read
Contents
Your business clients spend all day in Microsoft Teams. When something gets stuck, they message the project lead from the last meeting. If he's on vacation, nobody else sees the chat, and on Friday the client's boss calls you.
This guide covers the routes Microsoft offers for chats between companies, what IT on both sides has to allow, what data protection requires, and how private chats become one inbox for your whole team.
What breaks when support runs through private chats, calls and email
In October 2023 Microsoft reported more than 320 million monthly active Teams users, a figure the company itself gave on its quarterly earnings call. You can try to train your clients back into email. They'll still use the channel they already sit in all day.
As long as three clients write in Teams now and then, you barely notice. Once you have 20, it shows in these places:
- A private chat in Teams belongs to two people. If one of them is on vacation, off sick or no longer with the company, the request waits, and no colleague steps in because nobody else can see it.
- Whatever was promised on a Teams call isn't written down anywhere. The next colleague asks the client everything all over again.
- You don't know how long clients wait for an answer in Teams. These chats don't show up in any report, so there's no number your team can talk about.
- Support gets mixed up with project work. The question about the broken export sits between scheduling messages and the link to the Christmas party.
- Clients write twice, first in Teams and then by email to be safe. Two people reply, sometimes with different answers.
The fault lies in where the message goes. It lands with one person, and your team never gets to see it.
Three ways clients from other companies can reach you in Teams
Microsoft offers three ways to work with people outside your own organization. The one you use decides where your client can reach you at all.
| External access | Guest access | Shared channel | |
|---|---|---|---|
| What the client gets | Chats, calls and meetings with your people, but no access to your teams and channels | A guest account in your directory, and with it access to teams, channels and files | Access to exactly one channel, without a guest account |
| Do they have to switch organizations in Teams? | No | Yes | No |
| What has to happen first | Nothing, as long as both sides allow each other's domain. By default, access is on for all external domains. | A team owner invites the guest, as long as your IT allows guest access. | IT at both companies enables B2B direct connect, which is blocked by default. |
These details come from Microsoft's pages on external access, on external access compared with guests and on B2B direct connect.
A guest has to switch organizations
According to Microsoft, a guest has to switch organizations in Teams if they normally work in another Microsoft 365 organization. For a client who writes to you twice a month, that's a detour they soon forget.
After the invitation, it can also take up to 12 hours before a guest has access.
A shared channel needs both IT departments
With a shared channel, the client stays in their own Teams. But Microsoft Entra blocks the B2B direct connect this needs for all external organizations by default, and both sides have to enable it for each other.
You also can't add guests to a shared channel. Microsoft rules that out on its page about shared channels.
What a support app can do in Teams
According to Microsoft's developer documentation, a direct message from an app to someone outside its own organization fails. Conversations in a channel work, and in shared channels the app has to be added to each channel separately.
So a support app reaches clients from other companies in channel threads.
What your client's IT wants to know
The list of allowed domains
Microsoft turns external access on for all external domains by default. IT can limit it to a list of allowed domains or switch it off completely.
Both organizations have to allow each other, or no chat happens. If your client can't message you, their IT should check this list first.
Why some IT departments are cautious
In 2024 Microsoft described how the group Storm-1811 messaged and called targets over Teams, using display names like "Help Desk" and "IT Support" (Microsoft Threat Intelligence). Microsoft advises watching for the "External" label and never sharing account details in a chat.
For you as a service provider, that means: be easy to recognize. A channel with your company name and the line "We never ask for passwords" in its description does more for your client's IT than any explanation after the fact.
A request IT can act on right away
If you want a shared channel, send your client's IT a request that's already written out. Something like this:
We'd like to use a shared Teams channel with you for support requests. To set it up, please go to the cross-tenant access settings in Microsoft Entra and allow outbound access through B2B direct connect for our organization (example-itservices.com).
You can limit this to specific people or groups. On our side, we'll allow inbound access for you.
Microsoft itself says both administrators have to coordinate on this. A concrete request saves you several rounds of email.
Data protection: what to sort out before you start
This is general information, not legal advice. In Germany and Austria the GDPR applies, and in Switzerland the Federal Act on Data Protection (FADP). If you work in another country, check the rules there.
A contract with your support tool
If a support tool processes your clients' Teams messages on your behalf, you need a contract under Art. 28 GDPR in the EU.
In Switzerland, Art. 9 FADP allows you to hand processing to a processor if they handle the data only in ways you yourself would be allowed to, and no duty of confidentiality forbids the transfer. You also have to make sure the processor can guarantee data security.
What belongs in your privacy policy
Under Art. 13(1)(e) and (f) GDPR, your privacy policy names the recipients of the data and any planned transfer to a third country. The Swiss FADP asks for similar details in Art. 19, including the recipients and, for disclosure abroad, the country.
So list Microsoft Teams there as a channel, along with your support tool.
Which route the messages take
Chat apps in Teams run through Microsoft's Bot Service. Microsoft offers regional bots in Europe for this, but states itself that bot data can cross geographic boundaries because other services are involved.
Ask your provider to show you where their bot is registered and who is on their list of subprocessors.
When an AI answers
In the EU, Art. 50(1) of the AI Act has required since 2 August 2026 that people are told when they interact with an AI system, unless that's obvious from the circumstances.
If an app posts its notice only once, not everyone sees it. Anyone who joins later or reads along in another channel may never have read it. So put the notice in the channel description as well.
How to get started
- Pick out the five clients who already message you most often in Teams. Start with them before you tell everyone else about it.
- Decide for each client: if their IT is on board with B2B direct connect, use a shared channel. If not, invite your contacts there as guests to a support team on your side.
- In every channel description, say when you reply and that you never ask for passwords.
- Tell your people that client requests belong in the channel from now on. Anyone who still gets one in a private chat should politely ask the client to post it there again.
The last point matters most, because nobody but the recipient sees a request in a private chat.
Microsoft Teams as an inbox in Deskwoot
Deskwoot is our tool. It puts conversations from Microsoft Teams in the same inbox as live chat and email, such as email from your connected Outlook or Microsoft 365 mailbox.
Your team replies from there, and the reply shows up in the same Teams chat or thread with your team member's name in front of it. That way everyone sees the request, even while the project lead is lying on a beach.
Setup and limits
Your Microsoft 365 admin signs in once with their Microsoft account and uploads the Deskwoot app to Teams. Deskwoot keeps no password and no access to your organization.
Private channels and group chats don't work, and only the text of a channel post comes through, not its files. If a client ends up in the system twice, you merge the two contacts.
Fynn, our AI assistant, can answer first on the Startup plan and up, but in channel threads he only gives general answers. Questions about orders, payments or accounts stay with your team there, because several people read along.
Data and the AI notice
The app and database run in the EU (Netherlands). You sign the DPA in the dashboard, and its Annex B lists every service provider with its region.
Teams messages go through Microsoft's global Bot Service without its EU option and can also be processed outside the EU, for example in the United States. This is covered by the EU Standard Contractual Clauses and the EU-U.S. Data Privacy Framework (privacy policy).
The app posts the AI notice once when it's added, currently in English. Fynn's first answer also identifies him as an AI assistant.
What it costs
Teams works on every plan at no extra cost, the free Hacker plan included. Create a Deskwoot account and go through the Microsoft Teams setup guide with your Microsoft 365 admin.
When you sign up, you get 7 days of the Enterprise plan with Fynn, without a credit card and for up to 30 seats including yours.
Also available in:DeutschEspañolFrançaisPortuguês (Brasil)
