Turn OpenInvoice into an API

What you can build on OpenInvoice

• Check invoices requiring my attention

  Build this

  Reads the Invoices Requiring My Attention widget on the home page: your saved and disputed invoices, by workflow status, with each one's customer, date and amount.

  Takes

  Status (optional), customer (optional)

  Returns

  Invoice number, customer, customer site, invoice date, status, currency, amount

• Get approved and paid invoices

  Build this

  Reads the Approved Invoices widget on the home page: the invoices your customers have approved and the ones that have been paid.

  Takes

  Customer (optional), invoice date from (optional)

  Returns

  Invoice number, customer, invoice date, status, currency, amount

• Get field ticket statuses

  Build this

  Opens your field tickets from the Ticket icon on the menu and reads each ticket's number, customer, service date, status and amount.

  Takes

  Customer (optional), status (optional)

  Returns

  Field ticket number, customer, service date, status, amount

• Create and submit an invoice

  Build this

  Creates an invoice in the portal with its header fields and line items, attaches the backup tickets and submits it to the customer.

  Takes

  Customer, customer site, department, invoice number, date, currency, description, line items, backup file

  Returns

  Invoice number, customer, status, amount, validation errors

Automate OpenInvoice with a workflow

A workflow runs your methods as one process, with nobody at the screen. A schedule or a call from your own system starts it, the steps run in order, and the result arrives in your inbox or in the systems you already use.

• Newly disputed invoices, every weekday morning

  Build this

  Starts

  Every weekday at 7:00

  Step 1

  Check the invoices requiring your attention in Disputed status.

  Step 2

  Keep the invoices that were not disputed on the last run.

  Step 3

  Email you the list with invoice number, customer, invoice date and amount.

• Approved and paid invoices, handed to accounting

  Build this

  Starts

  Every Friday at 16:00

  Step 1

  Get the approved and paid invoices from the Approved Invoices widget.

  Step 2

  Keep the invoices whose status changed since the last run.

  Step 3

  Post invoice number, customer, status, currency and amount to your accounting webhook.

• Field ticket statuses, per customer

  Build this

  Starts

  Every weekday at 12:00

  Step 1

  For each customer you name, get the field ticket statuses.

  Step 2

  Keep the tickets whose status changed since the last run.

  Step 3

  Email you the changes, one section per customer.

You can run a workflow by hand on every plan, Free included. Schedules and webhook triggers come with the paid plans, from $29 a month.

Once built, one call from your code

Once you have built a method, it is one POST to /v1/runs from your backend, or a tool an AI agent calls over MCP. This is what “Check invoices requiring my attention” would look like.

curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "method": "openinvoice.com/check_invoices_requiring_my_attention",
    "input": {
      "status": "Disputed"
    }
  }'

{
  "status": "completed",
  "data": {
    "invoices": [
      {
        "invoice_number": "AC-20871",
        "customer": "Northwind Energy",
        "customer_site": "Northwind Energy - AP",
        "invoice_date": "2026-11-03",
        "status": "Disputed",
        "currency": "USD",
        "amount": 14250
      }
    ],
    "count": 1
  }
}

An example with invented data, not a ready-made endpoint. The method exists in your organization once you build it, and its name, inputs and fields follow your request.

OpenInvoice’s own options

Enverus offers SupplierLink, an optional suite for suppliers with transactional, reporting and validation APIs and invoice import from QuickBooks Online, QuickBooks Desktop or a file. It must be enabled for your company by the OpenInvoice Supplier Management team, in one of four subscription levels whose prices the help page does not list. Without it you create invoices and field tickets in the portal.

Read on November 12, 2026: SupplierLink overview, OpenInvoice supplier help: general information.

Signing in to OpenInvoice

OpenInvoice signs you in with a username and password, set up from a registration email along with security questions. A session times out after 30 minutes of inactivity. With Fous you sign in once through OpenInvoice's own sign-in with your own account: the login is sealed with AES-256, and an expired session is signed back in.

Worth knowing

One session at a time

If you sign in while a session is still running, OpenInvoice says you are already signed in and Continue ends the old session. A new tab in the same browser counts as the same session.

Your customer sets the fields and the words

Each buyer publishes its own invoice submission guidelines: in one, Invoice # takes at most 20 characters and line items carry AFE, Cost Center and PO Number. Buyers can also have the screens relabelled in their own terminology.

Wrong passwords lock the account

After a set number of wrong sign-in attempts the account locks, for 5 to 30 minutes or indefinitely, as your company administrator configured. Passwords expire on a schedule your administrator sets.

Exports are TSV files

Reports and exported files download as tab-separated values. In Excel, numbers longer than 11 digits turn into scientific format unless the column is set to Text.

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