Already compared with live EWS
202 scenarios ran through real EWS and through the library. Every difference found is listed on the compatibility page. After April 1, 2027 nobody can make that comparison again.
202 scenarios compared with live Exchange Online EWS.
The same code runs through real EWS and through Sunsetless EWS; the responses are compared field by field. See compatibility
- Runs on
- .NET Framework 3.5 to 4.8 and .NET 8, 9 and 10
- Works with
- Exchange Online and Exchange Server (hybrid)
56 EWS operations covered, and a plain list of the rest
Every area is marked as verified, verified with differences, or not possible in Microsoft Graph. Search the table by operation name. Load your EWS usage report to see which apps in it Microsoft or a vendor has to fix, and which operations of your own code are covered.
- Find and read mailVerified
- Meetings: invite, respond, cancelVerified
- Contacts: create, update and deleteVerified
- TasksVerified with differences
- Pull and streaming notificationsVerified with differences
- Public folders in Exchange OnlineNot possible in Graph
Three steps, no code changes
Sunsetless EWS translates EWS operations inside your application. Your app calls Microsoft Graph directly, with your own Entra app registration.
Swap the package
Replace
Microsoft.Exchange.WebServiceswithSunsetless.Ews. The namespace and types are the same, so your code compiles unchanged.Grant Graph permissions
Add
Mail.ReadWriteandMail.Sendto your Entra ID app, plus the calendar, contacts or tasks permissions your code needs. Limit it to the mailboxes it uses with RBAC for Applications.Set four configuration values
Tenant ID, client ID, a client secret or certificate, and your key. Calls to Exchange Online now run on Microsoft Graph. Calls to on-premises Exchange keep using EWS.
Why not just rewrite it for Graph?
A rewrite is what Microsoft recommends, and for a few simple calls it is the right choice. For everything else, compare the work.
One package reference instead of a rewrite
Namespace, types and methods stay the same. Your code compiles unchanged and calls Microsoft Graph underneath.
One code path for hybrid
Calls for Exchange Online go to Graph, calls for on-premises Exchange stay on EWS. You do not maintain two integrations.
Try it before you buy
Run your existing EWS code on Microsoft Graph, in your own tenant, before you pay for anything.
Free trial
$0
14 days in one tenant, no card needed.
We can also make the change for you, after a free check of your application. How it works
FAQ
- Is this a Microsoft product?
- No. Sunsetless is an independent company, not affiliated with, endorsed by, or sponsored by Microsoft.
- Does our mail go through your servers?
- No. Sunsetless EWS is a library that runs inside your application and calls Microsoft Graph directly with your own app registration. We never see your data.
- Can I try it before I commit?
- Yes. A free trial key runs the full library in your Microsoft 365 tenant for 14 days, and you do not need a card or a sales call to get one. After you buy, every license also has a 14-day money-back guarantee, no questions asked.
- What if my application calls something you do not cover?
- It gets a clear EWS error that names the operation. The library never returns partial data silently. The compatibility page lists what Microsoft Graph cannot do, and the free trial shows how your own code behaves.
- What if you stop developing it?
- Your application keeps running, because the license key is checked offline and nothing depends on our servers. The terms also have a sunset clause. If development stops, no release comes out for 12 months, or the business stops trading, every license holder gets the full source code of the latest release under the MIT license.
- Which license do I need?
- Single App covers one production application (one Entra app ID) in one Microsoft 365 tenant. Organization covers any number of applications in one tenant. ISV covers one product you ship to your customers, in any number of their tenants. Development, test and staging in the licensed tenant are included.
- Can you make the change for us?
- Yes. Send us your EWS usage report, or tell us what the application does, and we check it for free within one business day. We then quote a fixed price, from $1,000 on top of the license, for replacing the package, setting up the configuration and testing the application’s EWS calls against Exchange Online. You get the change with a list of every difference we found. If you have no team to release it, we do that too. Everything is agreed by email, and we work on one application at a time.
Keep your EWS code running after April 1, 2027.
Run your own code on a free trial key, or first check your usage report in the browser to see which apps in it are yours.