Dropbox stores PDFs perfectly. Editing them is where Dropbox stops. Dropbox Paper isn't PDF. The various Dropbox app integrations (HelloSign, DocSend) want subscriptions. For straightforward editing, the simplest path is two tabs.
The flow
Open Dropbox. Find the PDF. Click the three-dot menu → Download. Open Flint in another tab. Drag in the downloaded file. Edit, sign, or merge as needed. Download the result. Upload back to Dropbox.
Minute or two total. No add-on installs, no paid Dropbox features.
Replacing vs. saving new
Drag the edited file into Dropbox to upload. If you use the same filename, Dropbox keeps version history (Pro plans and above) so you can revert. For free Dropbox accounts, save as a new file (e.g. 'Contract_signed.pdf') to keep the original intact.
Shared links and edits
If someone shared a Dropbox PDF link with you, downloading and editing creates a local copy — your edits don't affect their original. To share the edited version, upload it to your own Dropbox and share that link, or attach by email.
FAQ
Does Flint integrate with Dropbox directly?
Not currently via OAuth. Manual download-edit-upload covers all use cases without permission grants.
Can I edit shared Dropbox PDFs in place?
Shared link viewers can't edit the original — that's by design. Download a copy, edit, share back as a new file.
What about Dropbox Smart Sync?
Smart Sync keeps files cloud-only until needed. PDFs in Smart Sync download automatically when you open them. Edit, save, and Smart Sync re-syncs the changes.
Dropbox stores, Flint edits. Two browser tabs, no add-ons.