The Document Server is installed and its welcome page loads — but Nextcloud knows nothing about it yet. The connector app is the introduction: three values, one Save button, and a connection check that tells the truth about your setup.
Installing the Document Server is only half the job. Until Nextcloud is told where the editor lives and given the matching secret, clicking a document still does nothing useful. That introduction is done by the official ONLYOFFICE connector app — it is small, free, and honest about whether the connection works. This page walks the connector step by itself, because getting it right here saves you from chasing strange editor errors later.
In Nextcloud, log in as an administrator and open Apps. Search for ONLYOFFICE, then download and enable it. This is the official integration app from the Nextcloud app store — it adds the ONLYOFFICE section to the admin settings and the editor wiring to the Files app. There is no file to upload and no code to edit for this step.
Go to Settings → ONLYOFFICE. You will see the basic fields first and an Advanced settings area underneath. Leave the advanced area alone for a standard install — it exists for split internal and public addresses, which the troubleshooting guides on this site cover when you actually need them. For a normal setup, the two basic fields do everything.
In the Document Server address field, type the exact address where your Document Server answers — for example https://office.example.com. This is the address your users' browsers will load the editor from, so it must be reachable from their machines, not just from the Nextcloud server. A name that only resolves inside the server room is a classic reason the editor works for the admin testing locally and fails for everyone else.
In the Secret key field, paste the same value you set as JWT_SECRET when starting the Docker container. Not a new secret, not a similar one — the same string, character for character. The two servers use this shared secret to sign their requests to each other. If you did not set your own secret at install time, find out what the container is using before this step, or restart the container with a secret you choose and control — the JWT guide on this site explains the reboot trap that makes this important.
Press Save. The connector does not just store your values — it immediately tries to reach the Document Server and verify the secret. A success message means the two servers genuinely trust each other. A failure message is useful information, not a dead end: an address error means Nextcloud could not reach the server at all, while a token or secret error means it reached the server but the keys did not match. Fix the side the message names instead of changing settings at random.
Settings pages can say success while a user's browser still fails, so finish with a real test. Log in as a normal user, upload a Word document, and click it. The OnlyOffice editor should open with the document inside. Make a small edit, close the tab, give it a few seconds, and reopen the file — your edit should be there. Only now is the connector honestly done.
JWT_SECRET of the Document Server container and the connector settings in Nextcloud. Whenever you change one, change the other in the same sitting. Most "it suddenly stopped connecting" stories are just these two values quietly disagreeing after a reinstall or an update.
The full OnlyOffice Document Server install and Nextcloud integration, shown live step by step.
▶️ Watch Full VideoIt is the value you chose yourself: the JWT_SECRET you passed to the Docker container at install time. If you let the container generate one, check the container's environment or restart it with a secret you set — and then use that same value in Nextcloud.
Make sure you are logged in as an administrator and your Nextcloud version is supported by the current connector release. App store visibility can also depend on your Nextcloud's app store connection — refresh the apps page and search again for ONLYOFFICE.
Yes — update the address in Settings, then ONLYOFFICE, and save so the connection test runs again. Remember that documents open in users' browsers, so the new address must be reachable from their networks too, not only from the server.