Skip to content

FousARBA

Get your ARBA returns and deductions through an API

Read the deducciones (deductions) agents reported against your CUIT, the state of each DDJJ (tax return) and the COTs you generated on ARBA with one API call each. A workflow can hand the month's retenciones and percepciones to accounting before you file.

Start building freeBook a demo

Works with your own ARBA account. Fous is an independent product.

What you can build on ARBA

  • Get the month's deductions

    Build this

    Reads CONSULTAS - DESCARGA DE DEDUCCIONES in DDJJ web for one year and month: the retenciones and percepciones agents reported against your CUIT.

    Takes
    Year, month
    Returns
    Type, CUIT del Agente, fecha de deducción, sucursal and emisión numbers, importe

  • List your Ingresos Brutos returns

    Build this

    Reads Consultas de DDJJ pendientes and CONSULTAS DDJJ CERRADAS ANTICIPO in DDJJ web: every periodic return with its state and dates.

    Takes
    Year, pending or closed
    Returns
    Número de comprobante, estado, régimen, año, período, tipo, fecha de inicio, fecha de cierre

  • Look up COTs by trip date

    Build this

    Reads Consulta de COTs in the COT system for a range of fechas de origen, including COTs generated through S.I.Ap.

    Takes
    From date, to date
    Returns
    COT number, fecha de origen, origin address, transport type, carrier CUIT, dominio, emitter CUIT

  • Add a retention to an open A-122R return

    Build this

    Loads one retention by Carga Manual into an A-122R return already started for an activity and period, and returns the comprobante number.

    Takes
    Activity, year, month, quincena, CUIT retenido, número de transacción agente, alícuota, amounts
    Returns
    Comprobante number, CUIT retenido, observation on the alícuota

Automate ARBA 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.

  • Month's retenciones and percepciones, sent to accounting

    Build this
    Starts
    Monthly on the 5th at 8:00, Buenos Aires time
    Step 1
    Get the deductions for the previous month from DESCARGA DE DEDUCCIONES.
    Step 2
    Group them by type and by CUIT del Agente with an AI step, and total each group.
    Step 3
    Post every deduction and the totals to your accounting system's webhook.

  • Ingresos Brutos returns still pending

    Build this
    Starts
    Every Monday at 9:00, Buenos Aires time
    Step 1
    List the returns in Consultas de DDJJ pendientes for this year.
    Step 2
    Stop when there are none.
    Step 3
    Email you each pending DDJJ with its período, tipo and fecha de inicio.

  • Today's COTs, posted to your warehouse system

    Build this
    Starts
    Every weekday at 19:00, Buenos Aires time
    Step 1
    Look up the COTs with today's fecha de origen.
    Step 2
    Keep the COTs that were not there on the last run.
    Step 3
    Post each COT number, carrier CUIT, dominio and emitter CUIT to your warehouse webhook.

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 the month's deductions” 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": "arba.gov.ar/get_deducciones",
    "input": {
      "year": 2026,
      "month": 10
    }
  }'
Example response
{
  "status": "completed",
  "data": {
    "period": "2026-10",
    "deductions": [
      {
        "type": "Retenciones",
        "agent_cuit": "30-71234567-1",
        "date": "2026-10-14",
        "branch_number": "00003",
        "issue_number": "00018422",
        "amount": 48210.55
      }
    ],
    "count": 1,
    "currency": "ARS"
  }
}

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.

ARBA’s own options

ARBA documents an API for collection agents under the A-122R withholding regime: start a return, add or delete retention receipts and get a receipt as PDF. COTs can be requested by sending a text file of remitos to a web service with your clave de transporte. Filing Ingresos Brutos returns and reading your deductions happen in DDJJ web, which offers a TXT download.

OptionWhat it coversWhat it takes
A-122R API for collection agentsInicio de DJ, Alta and Baja de Comprobante, and Consulta del Comprobante as PDF, with a test environment and Swagger.A token generated by the agent's own CUIT. ARBA says it will set accepted traffic limits.
COT remitos file serviceSends a pipe-separated text file of remitos by HTTPS POST and returns an XML result for each remito.Your CUIT and clave de transporte as user and password, and a file named and laid out to ARBA's published design.
DDJJ web downloads and batch loadsDESCARGA DE DEDUCCIONES gives a month's deductions as a .TXT file. Carga por lote imports your own deductions from a file.CUIT and CIT. Bimestral taxpayers download each month separately.
ARBA by handDDJJ web, the A-122R application and the COT system, one screen and one period at a time.Your CUIT and CIT, or for COT your CUIT and clave de transporte.

Read on November 12, 2026: Interfaz de los Servicios A122R Api Externos, version 2.0, Remito electrónico automático, instructivo, Instructivo Presentación Web DDJJ IIBB Periódicas y Anuales.

Signing in to ARBA

DDJJ web and the A-122R application sign you in with your CUIT and your CIT (Clave de Identificación Tributaria). The COT system uses a separate clave de transporte, valid only for transporting goods. With Fous you sign in through ARBA's own sign-in with your own CUIT: the login is sealed with AES-256, code and AI agents never see it, and an expired session is signed back in.

Worth knowing

Two different passwords
The clave de transporte you get for COT is valid only for transporting goods, not for Ingresos Brutos. DDJJ web and the A-122R application use your CIT, so each method signs in with the one its system asks for.
A closed return cannot be changed
A retention in a closed A-122R return cannot be deleted or fetched as PDF. Starting a return for a closed period creates a rectificativa, where you enter only the changes.
Transaction numbers are used once
The número de transacción agente cannot repeat for the same activity and period, even if the receipt was deleted. Deleting a receipt notifies the retained taxpayer through the Domicilio Fiscal Electrónico.
Recent COTs may be missing for a moment
COTs generated through S.I.Ap just before a search may not appear for a moment. Run a daily COT lookup late in the day, not right after the trips are declared.

More in Government: Latin America

Other industries: SARS eFiling, Mercell, FinanzOnline, eFileIL, HM Land Registry portal, EPA Central Data Exchange.

Frequently asked questions

Yes, for parts of it. Collection agents under A-122R have an API to start a return, add and delete retention receipts and fetch a receipt PDF, and COTs can be requested by posting a remitos text file to a web service. Ingresos Brutos returns and your deductions are in DDJJ web, with a TXT download.

In DDJJ web, under CONSULTAS - DESCARGA DE DEDUCCIONES, for one year and month. Inside a return they appear in the Retenciones, Percepciones, Percepciones Aduaneras, Retenciones Bancarias and Retenciones Sirtac tabs, with the CUIT del Agente, date and amount.

Yes. Consultas de DDJJ pendientes in DDJJ web lists each return that was started but not sent, with its número de comprobante, estado, régimen, período, tipo and fecha de inicio. A pending return is closed with ENVÍO.

The COT system asks for your CUIT and a clave de transporte. ARBA says that key is valid only for transporting goods and not for Ingresos Brutos, so you keep both.

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

Put ARBA 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.

Start building freeBook a demo

Read nextSEACESECOP IIBPS Servicios en LíneaSARS eFilingHow methods workHow workflows run

Fous is an independent product: it is not affiliated with, endorsed by or sponsored by the operator of ARBA (Agencia de Recaudación de la Provincia de Buenos Aires). 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.