Slack is where work PDFs land more and more — quote from sales, contract from legal, spec from product. Slack lets you preview them, comment on them, but not edit them. The fix is one tab away.
The flow
Click the PDF in the Slack message. Click Download (download icon). Open Flint in your browser. Drag the file in (Slack desktop downloads to your Downloads folder; Slack web does the same in browser).
Edit. Download the corrected version. Back in Slack, drag the new file into the conversation or reply with + Attach.
Threaded sharing
Best practice in Slack: reply in the thread (not a new top-level message) so the edit history is contained. Mention what you changed: 'Updated the date and signed — attached.' Recipients see the file in context.
Big files and Slack limits
Slack free tier caps storage; uploaded files older than 90 days disappear. Compressing PDFs before sharing saves quota. Compress in Flint first — typical scans drop 80% with no visible quality loss.
FAQ
Can I edit Slack PDFs inline?
No — Slack's preview is read-only. Download, edit, re-share is the flow. Slack's roadmap has hinted at richer document handling but for now, external tools handle editing.
Will my edit replace the original in Slack?
No — your upload is a new file. The original stays where it was. Mention in the thread that the new file supersedes the original.
What about Slack Canvas?
Canvas is Slack's collaborative document tool, separate from PDFs. For native Canvas editing, use Slack's tools. For PDFs, the download-edit-reupload flow is correct.
Slack shares, Flint edits. Re-share in the thread. Clean workflow.