Chase overdue Invoice Ninja invoices

1. Open Invoices and look for invoices past their Due Date. An invoice with no Due Date is due immediately, so it never shows as late.
2. Click a row to open the overview panel, check the balance owing and the status, then open the Email History tab to see when the client last got an email.
3. Choose More Actions > Email Invoice to resend it to the contacts checked to receive it.
4. For a standing routine, set up to three reminders under Settings > Templates & Reminders, for example 3 days before the due date, 7 days overdue and 30 days overdue. Each reminder can add a flat fee or a percentage as a new line on the invoice.
5. Each client has a Send Reminders switch on the client record, so a client who was switched off there gets nothing from the schedule and the invoice waits until you look at it.

List my overdue Invoice Ninja invoices. Skip any that were emailed in the last 7 days, resend the first reminder for the ones under 30 days late, and list the rest for me with the balance.

1. 01

   Pull the overdue list

   Your agent calls list_invoices with overdue set and pages through the cursor. It keeps invoices in Sent or Partial status with a balance above zero and never touches drafts or cancelled invoices.

2. 02

   Check what the client already got

   get_invoice returns the email log and linked payments for each one. An invoice emailed in the last 7 days, by you or by an automatic reminder from Settings, is skipped, so a client never gets two nudges in one week.

3. 03

   Sort by how late

   Your prompt sets the lines, for example under 30 days gets a reminder and over 30 days goes to you. The agent shows days past due and the balance next to each invoice so the sorting is easy to audit.

4. 04

   Resend with the right template

   send_invoice emails the invoice again with the reminder template you named, and it asks for your OK per call until you switch confirmation off. Invoice Ninja adds a late fee only if your reminder settings define one; the agent never adds a fee itself.

5. 05

   Hand over the rest

   Invoices past your cutoff are listed with client, balance and last email date, so the call you make has everything in one line.

Overdue invoices: 5, open balance 6,350.00 USD
Resent reminder 1 (3):
- INV-0038 Brightwave Ltd, 14 days, 1,800.00
- INV-0033 Kestrel Labs, 22 days, 2,100.00
- INV-0035 Orchard & Finch, 9 days, 300.00
Skipped (1): INV-0036 Northwind Studio, emailed 3 days ago
Left for you (1): INV-0031 Fenwick Ltd, 41 days, 950.00

curl -X POST https://cotlet.dev/api/v1/invoice-ninja/invoices/INV-0038 \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"template":"reminder1"}'

{
  "invoice_number": "INV-0038",
  "status": "sent",
  "template": "reminder1",
  "sent_to": [
    "ap@brightwave.example"
  ],
  "sent_at": "2026-10-14T09:00:00+02:00",
  "balance": 1800
}

MCP: add https://cotlet.dev/mcp/v1 with the same key; the call is invoice_ninja_write → send_invoice. Example data.

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