I'm creating an internal site for my users and I don't want to be constricted by the limitations of hosting a site through Google sites.
But I also want to be able to embed Google documents and sheets.
Is this possible?
It certainly is possible. On the Google spreadsheet you want to use, click on "File" and then "Publish to the web". This also applies to other file formats of the Google editors (documents, drawings and slides).
On the resulting popup, click on the "Publish" button and then on the "Embed" tab. You should see an iframe
that can be copied onto any valid html page.
Copy the iframe and paste it somewhere on your site.
Editing
The above will provide a read-only view of the Google sheet. If you want your users to be able to edit the sheet, you'll need to share it with them or make it open to the public.
Once you've shared the sheet with the relevant parties, copy the link and replace the src
in the iframe
with the new link. You should then have something like the following:
References
Publish a document, spreadsheet, presentation, or drawing - Google Docs editors Help