FileCloud already has the connector. Give it your SumOffice address.

FileCloud Server has a WOPI client in Settings → Web Edit. It reads one discovery document and opens the matching editor inside FileCloud. There is no plugin to patch into FileCloud and no document relay: FileCloud remains the file host, while SumSheet, SumDoc and SumSlide run on your own server.

What the connection uses

FileCloud side	The built-in Web Edit WOPI client, configured by the FileCloud administrator.
SumOffice side	One HTTPS address exposing `/hosting/discovery` for SumSheet, SumDoc and SumSlide.
Files	`.xlsx`, `.xlsm` and `.xlsb` go to SumSheet; `.docx` goes to SumDoc; `.pptx` goes to SumSlide.
Storage	The bytes travel between FileCloud and the editor over WOPI. They do not pass through a SumOffice cloud account.

Step 1 — start the three editors

Run the SumOffice server behind the address your FileCloud container and your users can both reach. Use HTTPS in production.

git clone https://github.com/SumOfficeApp/sumoffice-docker
cd sumoffice-docker/nextcloud
cp env.example .env
# PUBLIC_URL=https://office.example.com
docker compose up -d
curl -fsS https://office.example.com/hosting/discovery | head -c 300

The compose directory is named nextcloud because that was its first host. The service itself is a WOPI editor endpoint and is used by FileCloud in exactly the same way.

Step 2 — activate FileCloud and finish storage setup

FileCloud Server requires its own FileCloud license. Install it in the administration interface, set the storage path, and finish the first-run screens before configuring Web Edit. The license belongs to FileCloud; it is never copied into the SumOffice containers or into a deployment repository.

Step 3 — configure Web Edit

Open Settings → Web Edit as the built-in FileCloud administrator and set:

WOPI client	`Collabora Code`
WOPI client zone	`External HTTPS` for production; use the matching HTTP zone only on an isolated test stand.
WOPI client host	`office.example.com` — host name only, without `https://` and without `/hosting/discovery`.

Turn on the Web Edit switches for preview and editing. Press Save first and Configure second. A successful discovery check changes the client to Configured.

Step 4 — prove the return path

Upload one healthy .xlsx, .docx and .pptx to My Files.
Open each with Web Edit, make a visible change and save it.
Download the three results and inspect their OOXML: the changed cell, document text and slide text must be present, and each ZIP must open without repair.

Three FileCloud-specific traps

Host field	Do not paste a URL. FileCloud adds the scheme from the selected zone and appends `/hosting/discovery`. A value beginning with `https://` becomes an invalid double-scheme address.
Button order	Configure does not perform the discovery request until the settings have been saved. Save, then configure.
Server architecture	The FileCloud Docker image is distributed for `linux/amd64`. Use an x86-64 host for acceptance and production; emulation is suitable for configuration work, not performance figures.

Licensing boundary

FileCloud Server and SumOffice are licensed separately. A FileCloud evaluation activates the host; the SumOffice evaluation lets the same organization test the editors without counting people, files or folders. Production SumOffice licensing is per embedding application. Terms and the production boundary →

Then

Ask for a FileCloud acceptance session — we will verify the three returned OOXML files with you.
See the same server connected to other WOPI hosts.