Client portal with order history and report export

We sell wholesale, and today every document a customer needs goes through a phone call to a manager. Somebody asks for last quarter invoices, a manager digs the files out of a shared folder, renames them and sends them over one by one. In season this eats half the working day of the sales team, and the customer is still unhappy, because he waits his turn instead of getting the paper he already paid for. I want to close that loop with a proper client portal where the buyer takes what he needs himself, without calling anyone.

Sign-in is by invitation only: we send the invite, the customer sets his own password. There are two roles. The owner sees everything under his company, invites and removes staff, edits company details and switches on two-factor sign-in for himself. Staff members read the order history and download documents, but they cannot invite anyone and cannot touch company details. The order history needs filters by date range and by status, invoices and delivery acts available for download, and a way to export the current selection to XLSX and PDF, so that the buyer can hand the same numbers to his own accountant.

Orders and documents are pulled from our accounting system rather than typed in twice; it has an API and the documentation is written, we hand it over together with test credentials. Shipment notices go out by e-mail. The layout has to survive a phone screen, because half of our buyers open this kind of thing standing on a warehouse floor.

What the work has to cover:

— invitation sign-in, password chosen by the customer, two-factor sign-in for the owner role;
— two roles, owner and staff, with a clear list of what each one may do;
— order history with date and status filters, invoices and delivery acts for download;
— export of the current selection to XLSX and PDF, with the same columns the buyer sees on screen;
— e-mail notices about shipments;
— integration with our accounting system over its documented API;
— mobile layout for phones, not a shrunken desktop page;
— customer personal data is never exported outside the portal and never travels inside a letter in full: a message carries an order number and a short status line, the rest stays behind the sign-in;
— access to another company orders is closed at the query level, not only hidden in the interface;
— the test environment runs on depersonalized data, with no live customer records copied into it.