Documentation

What you need

• Windows 10 or 11.
• Microsoft Excel 2016 or later for Windows, 32- or 64-bit (Microsoft 365 included). Excel on a Mac or in a browser is not supported.
• The free Microsoft .NET 8 Desktop Runtime. The installer checks for it and shows the download link if it's missing.
• An XLStreaming account - sign up and verify your email first.

Steps

1. Sign in and open the download page; download XLStreamingSetup.exe.
2. Close Excel.
3. Run the installer and click Install. It installs for your Windows user only and needs no administrator rights.
4. Start Excel. An XLStreaming tab appears on the ribbon and you are asked to sign in.
5. Type =XLS.VERSION() in any cell to confirm the add-in is loaded.

Running the installer again updates or repairs an existing installation.

The browser says the download "isn't commonly downloaded" or "may be harmful"

Edge: open the Downloads list, point at the file, click the … menu and choose Keep, then Show more › Keep anyway. Chrome: in the Downloads list choose Keep. Other browsers have a similar option.

"Windows protected your PC" (SmartScreen) when you run the installer

Click More info, then Run anyway. If there is no "More info" link, your organisation has locked SmartScreen down - ask your IT team to allow XLStreamingSetup.exe.

Checking you have the genuine file

Because the file isn't signed, you can verify it by checksum instead. Next to the download we publish XLStreamingSetup.exe.sha256. In PowerShell, in your Downloads folder:

Get-FileHash .\XLStreamingSetup.exe -Algorithm SHA256

The hash shown must match the one in the .sha256 file. If it doesn't, delete the file and tell us. Only ever download the installer from xlstreaming.com.

Antivirus quarantined or deleted the installer

Restore it from the antivirus quarantine and add an exception for XLStreamingSetup.exe and the folder %LOCALAPPDATA%\XLStreaming. If your antivirus keeps flagging it, please email us the product name and the message - we report false positives to vendors.

"Microsoft Office has identified a potential security concern"

Excel shows this for an unsigned add-in. Choose Enable this add-in for this session only. Until the add-in is signed, Excel may ask each time it starts - we know this is annoying and signing will remove it.

Nothing happens: no XLStreaming tab, =XLS.VERSION() gives #NAME?

1. Trust Center settings. In Excel go to File › Options › Trust Center › Trust Center Settings › Add-ins. If Require Application Add-ins to be signed by Trusted Publisher or Disable all Application Add-ins is ticked, Excel silently refuses unsigned add-ins. Untick it if you are allowed to, restart Excel, and try again. In many companies this setting is controlled by IT - ask them to allow the add-in, or wait for the signed version.
2. Disabled items. File › Options › Add-ins; at the bottom choose Manage: Disabled Items › Go. If XLStreaming is listed, select it and click Enable, then restart Excel. Excel disables an add-in that crashed during start-up, which can happen when the .NET 8 runtime is missing.
3. The file is blocked. Open %LOCALAPPDATA%\XLStreaming\AddIn in File Explorer, right-click the .xll file, choose Properties, tick Unblock at the bottom of the General tab and click OK. Restart Excel.
4. .NET 8 Desktop Runtime. Run the installer again; it tells you if the runtime is missing and links to it. Install the one matching your Excel (x64 or x86) - the installer picks the right link.
5. Repair. Run XLStreamingSetup.exe again and click Install; it re-registers the add-in.

Excel Add-ins dialog doesn't show it

That's expected. The add-in is registered to load at start-up rather than through the Add-ins dialog, so it won't appear under Manage: Excel Add-ins. Use the Disabled Items check above instead.

Command-line use: XLStreamingSetup.exe /quiet installs silently (exit codes: 0 ok, 1 error, 2 no Excel, 3 Excel is open); XLStreamingSetup.exe /uninstall removes it.

"Keep me signed in" stores a refresh token, encrypted by Windows for your user account, in %APPDATA%\XLStreaming. Your password is never saved.

Publish

1. Select the cells you want to share.
2. On the XLStreaming tab click Publish Selection and give the stream a name.
3. The add-in writes an =XLS.PUBLISH(...) formula; the range is now live. Changes are sent as you make them.
4. Share adds readers by email - they get a link and are approved in advance.

Listen

1. Click Listen to Stream and pick a stream shared with you, or paste its id.
2. The add-in writes an =XLS.LISTEN(...) formula that spills the whole table into the sheet, number formats included.
3. If you haven't been approved yet the cell says so; the owner sees your request under Requests (and on their dashboard) and the data appears when they approve.

No Excel? Your dashboard has a Browser viewer link that shows a stream live in any browser. Readers can't change the data; only the publisher can.

Good to know

• One live publisher per stream. Publishing the same stream from a second place takes it over and stops the first, with a notice.
• Very fast sheets are throttled to about four updates a second per stream; the latest values always win.
• When a workbook that listens is reopened it shows its last values, marked Cached, until it reconnects.
• Your dashboard shows your streams, who can see them, who is listening now, and your recent sign-ins.

Excel's Insert Function dialog (fx) describes the arguments. A fuller reference, and the REST / Python documentation, will follow here.

Uninstall: Windows Settings › Apps › Installed apps › XLStreaming Add-in › Uninstall, or run XLStreamingSetup.exe /uninstall. This removes the add-in, your saved sign-in and the offline copies of streams you listened to. Your settings are kept.

Log file: the Log File button on the XLStreaming tab shows where it is (normally %APPDATA%\XLStreaming) and opens it. If you report a problem, attaching the log helps a lot. It never contains your password; have a quick look through it first if your sheet holds anything sensitive.