Deal document room connecting HubSpot to Amazon S3

Build me a deal document room app that connects HubSpot to Amazon S3. It is for sales and deal desk people who need to see and manage the contracts and forms attached to a deal, and who should never have to open the AWS console. HubSpot holds the deal record, S3 holds the actual files, and this app is the single screen that joins them.

Landing view: a list of my open deals. Use HubSpot Search Deals filtered to the pipeline stages I have marked as open, and show deal name, stage, amount and close date, sorted by close date so the soonest deals are at the top. Across the top, show a summary bar with how many open deals are missing paperwork, how many are complete, and how many have an expired document, so the team can see where the gaps are. Clicking a deal opens its document room.

Document room, left side: the required documents checklist for that deal's current stage. Seed it with signed order form, security review, W9, MSA and purchase order, but the checklist must be editable and configured per stage rather than hardcoded, so an early stage can require fewer documents than a stage about to close. Each row shows the item name and a status of matched, missing or expired. Refresh the deal's current stage and properties with HubSpot Get Deal when the room opens.

Document room, right side: the files already stored for that deal. Use S3 List Objects (V2) against a prefix built from the deal ID, following a key convention the user configures once in settings (for example deals/{dealId}/). For each object show the filename, size and upload date, using S3 Head Object for the size and last modified date. Show an empty state that explains where files should go when the prefix has nothing in it yet.

Matching a file to a checklist item works two ways. First, by a filename convention I can configure per checklist item, for example a pattern or keyword like w9 or order-form. Second, and taking priority, by the tag stored on the object itself: when I tag a file with the checklist item it satisfies, read that tag back with S3 Get Object Tagging so the match survives a rename. A checklist item counts as expired when its matching file's upload date is older than a validity window I can set per item, which matters for things like tax forms and security reviews.

Actions in the room: drag a file onto the room to upload it with S3 Put Object, writing it to the correct key under that deal's prefix, and let me pick which checklist item it is for so the key and tag are set correctly. Open or download anything already there with S3 Get Object. Tag an existing file with the checklist item it satisfies using S3 Put Object Tagging. After any upload or tag change, re-evaluate the checklist so the statuses update immediately.

When every required document for the stage is present and none is expired, enable a "Mark documents complete" button. It writes back to the CRM in two steps: HubSpot Update Deal sets a documents status property that I nominate in settings, and HubSpot Create Note logs a dated note on the deal listing the filenames received and their upload dates. Keep the button disabled with a clear reason when something is still missing or expired.

Settings screen, persisted for the workspace: the S3 bucket name, the key prefix convention built from the deal ID, which pipeline stages count as open, the per-stage checklist of required documents, the filename matching rule and validity window for each checklist item, and which HubSpot deal property receives the document status. Everything about the checklist should be data the user edits in the app, never values baked into the code.