Chase overdue Xero invoices with Adyen payment links

Build me an app my finance team opens each morning to chase unpaid invoices and get paid by card. Xero is the invoice source, Adyen pay by link is the payment rail, and the app itself is the record of every link we have sent. This is a working surface for collectors, not a report: the operator decides which invoices to chase, sends the link, and works the queue down.

Main view: the outstanding invoice worklist

The landing view is a worklist of outstanding sales invoices loaded with Xero List Invoices, filtered to authorised invoices that still have an amount due, sorted by days overdue with the latest first. Columns: invoice number, customer name, invoice total with its currency, amount still due, due date, days overdue, current link status, who created that link, and the date it was last chased. Support filtering by collector, by minimum amount, and by a days-overdue threshold, plus a Mine toggle that narrows the list to links the current user created.

Two Xero data notes to handle: money fields come back as decimals such as 99.95 rather than cents, and dates arrive in .NET format like /Date(1551830400000+0000)/, so parse the millisecond timestamp before computing days overdue. Xero list responses are wrapped in a plural collection key and are paginated, so page through until every outstanding invoice is loaded.

Detail pane

Selecting a row opens a detail pane. Call Xero Get Invoice for the full record including line items, and Xero Get Contact for the customer behind it. Show a line items table with description, quantity, unit amount, tax and line total, a customer block with email, phone and billing address, and the full history for that invoice: every payment link created against it with its status and creator, and every chase note.

Create Payment Link

Every row has a Create Payment Link button, repeated in the detail pane. It calls Adyen Create Payment Link with the amount taken from the invoice, the merchant account from settings, an expiry date from the configurable default of 14 days, and the customer email from the Xero contact as the shopper email when one exists.

Two things must be exactly right here. First, the amount. Adyen takes amount as an object shaped { currency, value } where value is in MINOR units, so 1000 means EUR 10.00, while Xero gives you a decimal. Convert by multiplying by 100 for normal two decimal currencies, passing the whole number for zero decimal currencies such as JPY, and using thousandths for three decimal currencies such as BHD. Round to an integer carefully so floating point never shifts a cent. Use the invoice currency, never a hardcoded one. Second, always set reference to the Xero invoice number, because that is the string finance reconciles against when the money lands.

Create the link for the amount still due rather than the original total, so partly paid invoices request the right remainder.

App storage is the system of record

This is the constraint the whole app design hangs on. Adyen has no operation that lists or searches payment links, and no operation that lists payments. Adyen Get Payment Link only works when you already hold the link id. So the app must persist every link it creates and must never contain a view that assumes it can page through links or transactions held at Adyen.

On every successful creation, save to app storage: the Adyen payment link id, the hosted payment URL, the Xero invoice id, the Xero invoice number, the customer name, the amount value and currency, the current status, the expiry date, the creation timestamp, and the app user who created it. Keep the full history per invoice rather than overwriting, so a reissued link sits alongside the one it replaced.

Refresh Status

A Refresh Status handler loops over the stored link ids, calls Adyen Get Payment Link for each, and writes the result back to storage with a last-checked timestamp. Map the Adyen status values onto the three the app shows: active stays active, completed and paid both become Paid, expired becomes Expired. Handle an id that no longer resolves without failing the whole sweep, and show progress since this loops one call per stored link. Offer it as a button and run it automatically when the app opens if the stored statuses are stale.

Expired without payment

Give expired-and-unpaid links their own highlighted section at the top of the worklist, styled as needing attention, because these are invoices where someone did the work and the window closed. Each carries a Reissue button that creates a fresh Adyen payment link for the amount still due today and stores it against the invoice alongside the old one. When reissuing an invoice that still has an active link, call Adyen Update Payment Link Status first to expire the superseded link so the customer cannot pay through a stale URL.

Collector actions

Copy link puts the hosted payment URL on the clipboard in one click, with a visible confirmation, since collectors paste these into their own emails and calls. Mark as chased records the current user, the timestamp, and a free-text note against the invoice in app storage, then surfaces the most recent chase date and note in the worklist so nobody chases the same customer twice in a day. The detail pane shows the whole chase history.

Push a summary to Slack

A button posts a summary of outstanding links to a finance channel using Slack Bot Send a Message, with the channel chosen from a picker populated by Slack Bot List Channels and remembered in settings. Group the message by status: the outstanding total, the value sitting on live links awaiting payment, expired links needing reissue, and what has been collected this month. For each listed invoice include invoice number, customer, amount, days overdue, and who created the link.

Totals across the top

Three headline figures sit above the worklist: total outstanding value across the unpaid invoices in view, value that currently has a live link against it, and value collected this month from links that reached paid within the current calendar month. Group these by currency rather than adding different currencies into one meaningless number. Each total is clickable and filters the worklist beneath it.

Per-user attribution

Every link and every chase note is stamped with the person who did it, and the creator is a visible column in the worklist, not just stored metadata. A manager should be able to filter to one collector and see what they have sent, what came back paid, and what expired unworked.

Settings

A settings view holds the Adyen merchant account name, which Adyen requires in the body of each request and does not come from the stored credential, along with the default link expiry in days, the Slack channel for summaries, and the Xero organisation to read invoices from.