[solardev]

I don't know what the product is (and you probably don't want to say...?) but is it something that could potentially done clientside in their browser, maybe in JS or WASM? That way you never even have to receive, much less store, their document.

[wayoverthecloud]

Unfortunately, storing the document is required. Almost an essential feature.

[bootstrpppin]

That's a good idea - not sure how big the docs are, but would local storage be helpful?