Read your ARCA notifications by API

What you can build on ARCA

• List Domicilio Fiscal Electrónico communications

  Build this

  Reads the list in the Domicilio Fiscal Electrónico service for one CUIT, using its filters, without opening any message.

  Takes

  CUIT (own or represented), received from, received to, unread only (optional)

  Returns

  Received date, sender organisation, type (notification or message), subject, read or unread, CUIT

• Open a communication and read it

  Build this

  Opens one message in the Domicilio Fiscal Electrónico and returns its text. Opening it counts as being notified.

  Takes

  CUIT, received date, subject

  Returns

  Subject, sender organisation, received date, text, opened at

• Link an email address for new communications

  Build this

  Uses Asociar temas a un correo electrónico in the Domicilio Fiscal Electrónico to link an email address that gets a notice for each new communication.

  Takes

  CUIT, email address

  Returns

  CUIT, email address, linked or not

Automate ARCA 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.

• New Domicilio Fiscal Electrónico communications, every CUIT

  Build this

  Starts

  Every weekday at 8:00, America/Argentina/Buenos_Aires

  Step 1

  For each CUIT you name, list the communications received in the last 7 days, without opening them.

  Step 2

  Keep the ones that were not there on the last run.

  Step 3

  Email you the list, one section per CUIT, with sender, type and subject.

• Unread communications before Monday's notificación de oficio

  Build this

  Starts

  Every Friday at 10:00, America/Argentina/Buenos_Aires

  Step 1

  For each CUIT, list the unread communications in the Domicilio Fiscal Electrónico.

  Step 2

  Stop when there are none.

  Step 3

  Email you the list, so someone reads each one before it counts as notified on Monday.

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 “List Domicilio Fiscal Electrónico communications” would look like.

curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "method": "auth.afip.gob.ar/list_dfe_communications",
    "input": {
      "cuit": "30-00000000-0",
      "received_from": "2026-11-02",
      "received_to": "2026-11-12",
      "unread_only": true
    }
  }'

{
  "status": "completed",
  "data": {
    "cuit": "30-00000000-0",
    "communications": [
      {
        "received_date": "2026-11-10",
        "sender": "ARCA",
        "type": "Notificación",
        "subject": "Vencimiento declaración jurada IVA",
        "read": false
      },
      {
        "received_date": "2026-11-05",
        "sender": "Rentas provinciales",
        "type": "Mensaje",
        "subject": "Actualización de datos del padrón",
        "read": false
      }
    ],
    "count": 2
  }
}

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.

ARCA’s own options

ARCA offers SOAP web services for application developers: padrón lookups, Constatación de Comprobantes, Ventanilla Electrónica communications (WSCCOMU), VEP creation and more. Each needs an X.509 certificate, which ARCA issues free, and authorisation in the Administrador de Relaciones; some need special agreements with ARCA. Everything else is the Clave Fiscal services used by hand.

Read on November 12, 2026: ARCA Web Services SOAP: architecture, ARCA Web Services SOAP: catalogue, Domicilio fiscal electrónico: notificaciones.

Signing in to ARCA

ARCA signs you in with your CUIT and Clave Fiscal. A company acts through its legal representative's Clave Fiscal, and services can be delegated in the Administrador de Relaciones. Level 4, for customs declarations, adds a Token ARCA code. With Fous you sign in once through ARCA's own sign-in with your own Clave Fiscal: it is sealed with AES-256, never returned by the API, and an expired session is signed back in.

Worth knowing

Opening a message notifies you

A communication counts as notified when it is opened, or on the Monday after it becomes available, whichever comes first. A method that opens messages notifies you, so list them first.

Companies act through a person's Clave Fiscal

A legal entity uses ARCA through its legal representative's Clave Fiscal, set up as Administrador de Relaciones. Other people get access when services are delegated to them there.

The security level decides the services

Each Clave Fiscal level opens more services. Level 4, needed to make customs declarations official, requires level 3 first and adds an 8-digit Token ARCA code.

ARCA asks for a new Clave Fiscal after 365 days

ARCA asks you to change a Clave Fiscal that is more than 365 days old. A Clave Fiscal needs 2 numbers, 4 letters, 1 capital and 1 lower-case letter.

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