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FousSantander for Intermediaries

Track your Santander for Intermediaries cases by API

Build methods that read a case's MATS history and outstanding documents, or a client's existing Santander mortgage, from Introducer Internet in one API call. Then have a workflow check your pipeline cases each morning and email you what Santander still needs.

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Works with your own Santander for Intermediaries account. Fous is an independent product.

What you can build on Introducer Internet

  • Get outstanding documents for a case

    Build this

    Opens a case in MATS from Case tracking and reads Supply case information: documents outstanding, submitted but not yet accepted, accepted or no longer needed.

    Takes
    Case reference
    Returns
    Case reference, outstanding documents, documents awaiting acceptance, accepted documents, documents no longer needed, notes

  • Read a case's MATS history

    Build this

    Reads Case history in MATS for one case: the full history of the case and every message Santander has sent about it.

    Takes
    Case reference, messages since (optional)
    Returns
    Case reference, message date, message text

  • View a client's existing mortgage

    Build this

    Opens the Online Mortgage Transfer Service and reads Your current mortgage: each loan's LTV, product start and end dates, product code and transfer eligibility.

    Takes
    Mortgage account number, surname, date of birth, mortgaged property postcode
    Returns
    Loan parts, LTV, product code, product start date, product end date, eligible to transfer

  • Upload documents to a case

    Build this

    Opens Supply case information in MATS for a case, adds a note, selects the documents and submits them.

    Takes
    Case reference, documents, note
    Returns
    Case reference, documents submitted, submitted at

Automate Introducer Internet 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.

  • Outstanding documents across your pipeline cases

    Build this
    Starts
    Every weekday at 8:00
    Step 1
    For each case reference you list, get the outstanding documents from Supply case information in MATS.
    Step 2
    Keep the cases that still have documents outstanding or awaiting acceptance.
    Step 3
    Email you the list, one section per case, with the documents still needed.

  • New MATS messages, posted to your CRM

    Build this
    Starts
    Every hour
    Step 1
    For each case reference you list, read the case's MATS history.
    Step 2
    Keep the messages that were not there on the last run.
    Step 3
    Post each one, with case reference, date and text, to your CRM webhook.

  • Clients whose Santander deal ends soon

    Build this
    Starts
    On the 1st of every month at 9:00
    Step 1
    For each client in your list, view the existing mortgage in the Online Mortgage Transfer Service.
    Step 2
    Keep the loan parts whose product end date is in the next 5 months.
    Step 3
    Email you each client's mortgage account number and surname, with product code, end date, LTV and whether the loan is eligible to transfer.

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 “Get outstanding documents for a case” would look like.

Example request
curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "method": "introducers.santander.co.uk/get_outstanding_documents",
    "input": {
      "case_reference": "AA000482193"
    }
  }'
Example response
{
  "status": "completed",
  "data": {
    "case_reference": "AA000482193",
    "outstanding": [
      "Latest 3 months' payslips, applicant 2"
    ],
    "awaiting_acceptance": [
      "Bank statement, Northwind Bank, October 2026"
    ],
    "accepted": [
      "Proof of identity, applicant 1"
    ],
    "no_longer_needed": [
      "Accountant's certificate"
    ],
    "notes": [
      {
        "date": "2026-11-10",
        "text": "Bank statement for October attached, September to follow."
      }
    ]
  }
}

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.

Introducer Internet’s own options

Santander's intermediary site describes no API for brokers. Agreements in principle, full mortgage applications, document uploads, case tracking and product transfers are all done in Introducer Internet. MATS emails you at each stage of an application and sends daily progress summaries of your pipeline cases.

OptionWhat it coversWhat it takes
MATS email updatesAn email at each stage of an application, daily progress summaries of your pipeline cases, and emails asking for outstanding information.Your email address, or your admin's, on the application.
Admin usersAn administrator who keys and tracks applications, opens MATS and views mortgage offers on behalf of an intermediary.A request in Tools > Request a new admin user, then the intermediary adds the admin in Tools > Manage my admin users.
Introducer Internet by handAIPs, illustrations, FMAs, Case tracking and MATS, My offers and the Online Mortgage Transfer Service, one case at a time.Registration with Santander as an FCA authorised intermediary, an Introducer ID, password and passcode.

Read on November 12, 2026: How to use Introducer Internet, Tracking an application, Mortgage administrator user guide.

Signing in to Introducer Internet

Introducer Internet asks for your Introducer ID, password and passcode. After you register or re-register, Santander sends the passcode within 24 hours, and a forgotten password means registering again. With Fous you sign in once through Introducer Internet's own sign-in with your own account: the login is sealed with AES-256, and code and AI agents never see it.

Worth knowing

Documents within 15 working days
Supporting documents must reach Santander within 15 working days of the application being submitted, or the case is rejected and may need a new product. Santander asks you to package them together and upload them straight away.
Only the intermediary changes an application
Santander can only accept material changes to an application from the intermediary. The answers on the Application details page cannot be changed after Submit: a mistake there means a new application.
Admins work for one broker at a time
An admin user chooses which intermediary to work on behalf of after logging on, and a banner shows that broker on every page. An admin must be linked to at least 1 intermediary before they can log on.
Five tries in the transfer service
The Online Mortgage Transfer Service allows 5 attempts at a client's details before it locks you out, and access can take up to 72 hours to come back. A product transfer offer must be accepted, by you for the client, within 14 days.

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Frequently asked questions

Not one it describes for brokers. Applications, document uploads, case tracking and product transfers are done in Introducer Internet, and MATS emails you at each stage of a case with daily progress summaries. With Fous you can build your own methods on your own Introducer Internet account.

15 working days from submitting the application. After that the case is rejected and may need a new product selection. You can upload straight after submitting, through Introducer Internet or Supply case information in MATS, without waiting for the first MATS message.

Yes. Admin users can track applications in progress, view case tracking after submission, open MATS and access mortgage offers for the intermediary they choose at log on. You request one in Tools > Request a new admin user.

Santander says a decision takes about 60 seconds after you submit the AIP. The decision screen lists the documents Santander will need, which it confirms again at the full mortgage application.

No. Fous is an independent product. You use it with your own Introducer Internet account, and a method reads and does only what that account can.

Put Santander for Intermediaries behind an API call

Describe one job in Studio and see the method it builds, with 100 credits a month and no credit card, or book a demo and bring the sites your team signs in to.

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Fous is an independent product: it is not affiliated with, endorsed by or sponsored by the operator of Santander for Intermediaries (Santander UK). The name is used only to say which system this page is about. Something here wrong or out of date? Write to legal@fous.com.