Microsoft to Retire Azure Communication Services as a Standalone Offering on September 30, 2028

In September 2026, Microsoft announced that Azure Communication Services (ACS) will be retired as a standalone offering on September 30, 2028. ACS is the Azure service many applications use to send email and SMS, run in-app chat, and embed voice and video calling. The notice appeared in Microsoft's Azure Updates feed on September 24, 2026, and the details are set out in Microsoft's retirement and breaking changes guide.

If your product sends order confirmations, one-time passcodes or appointment reminders through ACS, or includes a chat or calling feature built on its SDKs, this affects you. The work is real but not urgent: Microsoft gives a two-year window. Any team planning web and mobile app development on Azure should also know that the door for new customers closes much sooner.

What Microsoft announced

Microsoft's guide states that ACS is being retired as a standalone offering effective September 30, 2028. It explains the decision as a shift toward communication features integrated into Microsoft's own platforms, naming Teams, Dynamics 365 and Azure, while working with third-party communications platform providers to cover the gaps.

The guide sorts every ACS product into one of two categories. A retired service will not be available after September 30, 2028. A service with a breaking change will continue to exist, but only in a form that requires changes to existing applications.

Which services are retired and which change

According to the impacted services table in Microsoft's guide, the following are retired outright:

• ACS Email, ACS SMS and Advanced Messaging with WhatsApp
• ACS Chat, including Chat for Teams meeting interop, and ACS Rooms
• Number Management (Direct Offer) and ACS Direct Routing
• Job Router
• The web and mobile UI Library SDKs

The calling side falls under breaking changes. The guide lists the Voice and Video Calling SDK, Call Automation, Call Recording, Call Diagnostics, Audio Streaming and Closed Captions in that category. Microsoft says these will remain available after September 30, 2028, but will be supported only when used with a Teams-aligned service: Teams Phone Extensibility, Teams Meeting Interoperability, or Teams Click-2-Call for Teams Voice Apps. Standalone scenarios that do not integrate with Teams will no longer be supported, and affected SDKs will signal the change with a new major version number.

The two dates to know

October 23, 2026: closed to new customers

Microsoft's guide states that beginning October 23, 2026, new customers cannot sign up for the retiring services. Customers with an ACS resource created before that date can keep using their existing resources during the transition. The guide adds that only existing customers whose resources already have ACS phone numbers can acquire new SMS numbers.

September 30, 2028: retirement

After this date, Microsoft says retired services are not supported and cannot be used, and that API and SDK calls depending on them may return errors. This is a hard stop, not a gradual loss of support.

What Microsoft recommends instead

The migration table in the guide pairs each service with Microsoft alternatives and third-party options. The pattern is that Microsoft's own replacements are tied to other licensed products, and some services have no Microsoft replacement at all.

For email, Microsoft points to Microsoft 365 High Volume Email and Exchange Online, both requiring Microsoft 365 licensing. The guide's own comparison describes High Volume Email as intended for sending within your tenant, which is a different job from emailing customers. For SMS, the table lists no Microsoft alternative, only marketplace partners. For chat, it points to Microsoft Graph chat APIs, which need a Teams license; for WhatsApp messaging and Job Router, to Dynamics 365 Contact Center. The UI Library has no listed replacement, and Microsoft suggests forking the open source code if you need it to keep evolving.

Third-party providers named in the guide include Infobip, Telesign, Luware and Talkdesk, with others available through the Microsoft Marketplace.

Support, service levels and data during the transition

Microsoft's guide says existing resources remain available through September 30, 2028, that customers continue to receive support, security updates and bug fixes under their Azure support plan, and that current SLAs and compliance certifications stay in place. Existing SDK versions keep working during the period.

Two caveats are stated. First, Microsoft says it is not able to commit to new feature development; the engineering team is focused on existing functionality and on critical security and stability updates. Problems caused by changes in browsers, mobile operating systems or upstream libraries are handled as break-fix issues through support tickets. Second, data does not outlive the service. The guide says chat messages, call recordings and operational telemetry are available for export, and that after the retirement date this data is decommissioned for retired and standalone services.

On cost, Microsoft says only that moving to the supported services may bring additional service costs, licensing costs, or both.

What this means for your business

This section is our interpretation, offered as guidance.

The effect depends on which parts of ACS your product uses. Transactional email and SMS are usually the easiest to move, because the application typically calls them from a small number of places. The slow parts are outside the code: verifying a sending domain with a new provider, building sender reputation, and registering or porting phone numbers, which in both the US and the UK can involve carrier or regulatory steps with their own lead times.

Custom in-app chat for consumers is harder. Microsoft's guide positions the Graph chat alternative for Microsoft 365 users and guests, and points workloads needing anonymous users or a white-label experience toward third-party providers. That generally means replacing the SDK in your web and mobile clients, reworking identity and tokens, and deciding what to do with message history. Embedded calling for customers who are not Teams users is in a similar position.

The October 23, 2026 date matters for projects in design right now. A new product that was going to adopt ACS should choose a different provider. Existing customers can keep building, but new features on a retiring service add to the eventual migration bill.

One architectural lesson applies beyond Azure. Applications that call a messaging provider through their own thin internal interface can switch vendors with far less rework than applications with vendor SDK calls scattered throughout.

What to do next

• Confirm whether you use ACS at all. Microsoft's guide lists Azure Advisor retirement recommendations and the Cost Management portal as ways to find affected subscriptions.
• List each ACS capability your product depends on and mark it as retired or breaking change using Microsoft's table.
• Decide per capability between a Microsoft alternative and a third-party provider, and check licensing requirements before committing.
• Plan phone number and sending domain moves early, since they depend on outside parties.
• Schedule a data export for chat history and recordings you need to keep, and check your own retention obligations with your legal adviser.

Mobile apps deserve extra lead time, because an SDK replacement has to go through app store release cycles and users update at their own pace.

Conclusion

Microsoft will retire Azure Communication Services as a standalone offering on September 30, 2028, with new sign-ups for retiring services closed from October 23, 2026. Email, SMS, chat and several other services go away entirely, while calling continues only alongside Teams. Two years is enough time to migrate calmly, provided the inventory and provider decisions happen in the first few months.

If you would like help assessing how deeply your application depends on ACS and what a replacement would involve, you can request a quote for a migration review.