A1 form — Posting to the EU / EEA / Switzerland / United Kingdom / Gibraltar

Registers a new posting period for a worker and generates the PDA1 certificate.

Common parameters

• test (number (1)) : For testing, add the test=1 parameter. It must be omitted in production.
• regimen (integer) : Scheme, 4 digits. Possible values:
  • 0111: General Scheme
  • Table of scheme codes (opens in a new tab)
• ccc (integer) : Contribution account code, 11 digits.
• dni (string) : Worker's identity document.
• nss (integer) : Social Security number, 12 digits.
• desde (date) : Start of the posting, format YYYY-MM-DD. The RED System only accepts dates within a ±90 day window of the current date; the endpoint rejects the request before reaching RED if the date falls outside that range.
• hasta (date) : End of the posting, format YYYY-MM-DD. Must be ≥ desde and ≤ 90 days from today.
• paises (array of strings) : 3-digit numeric ISO 3166-1 codes. For types 1, 2 and 4, send it with a single element (the array keeps a minimum of 1 country).
  • 724: Spain
  • Table of country codes (opens in a new tab).
• tipo_desplazamiento (integer) : Posting type. Possible values:
  • 1: A single country, period not exceeding 24 months. Send tipo_desplazamiento_1.
  • 2: A single country, period exceeding 24 months. Send tipo_desplazamiento_2.
  • 3: Two or more Member States (EU/EEA/Switzerland/United Kingdom). Send tipo_desplazamiento_3.
  • 4: Civil servant, air crew or special maritime scheme. Send tipo_desplazamiento_4.

Sub-object tipo_desplazamiento_1 (a single country, < 24 months)

Required when tipo_desplazamiento = 1.

• vinculacion_directa_empresa_espanola (S | N) : Does the worker maintain a direct link with the Spanish company only? Mandatory.
• sujeto_solo_seguridad_espanola (S | N) : Is the worker subject to Spanish Social Security only? Mandatory.
• enviado_por_empresa_o_teletrabajo (S | N) : Sent by their company or under a remote-working authorisation? Mandatory.
• opcion_actividad (integer) : Place where the activity will be carried out. Mandatory. Possible values:
  • 1: At a specific company, address or workplace (requires sending the lugar_actividad object described below).
  • 2: There is no fixed address for the activity.
• sustitucion_persona_desplazada (S | N) : Is the worker being sent to replace another person previously posted who has already returned? Mandatory.
• residente_espana_contratado_temporal (S | N) : Has the worker resided in Spain in the month before the start of the posting, been hired in Spain, and is this a temporary situation of less than 24 months? Optional. Only applies when sustitucion_persona_desplazada = N and only if TGSS presents the question on that screen; otherwise it is ignored.
• primer_contrato_espana (S | N) : Has the worker resided in Spain in the month before the start of the posting, and is this their first contract in Spain? Optional. Only applies when residente_espana_contratado_temporal = N and only if TGSS presents the question on that screen; otherwise it is ignored.

Object lugar_actividad (only when opcion_actividad = 1)

If tipo_desplazamiento_1.opcion_actividad = 1, the lugar_actividad sub-object must be sent with the posting address. If opcion_actividad = 2, this object is not sent.

• denominacion (string, max 75) : Name of the destination company or workplace. Mandatory.
• nombre_via (string, max 35) : Street name. Mandatory.
• numero (string, max 4) : Number. Optional.
• poblacion (string, max 10) : Town / locality. Mandatory.
• codigo_postal (string, max 8) : Postal code. Optional.
• pais_destino (string, 3 digits) : Numeric ISO 3166-1 code of the destination country. Mandatory.

Sub-object tipo_desplazamiento_3 (activity in two or more Member States)

Required when tipo_desplazamiento = 3.

• reside_en_espana (S | N) : Does the worker reside in Spain? Mandatory.
• tipo_actividad_residente (integer) : Type of activity of the resident worker. Required if tipo_desplazamiento_3.reside_en_espana = S. Possible values:
  • 1: Employed work only.
  • 2: Employed and self-employed work in different States.
  • 3: Civil servant carrying out employed/self-employed work in another State or States.
• actividad_25_porciento_espana (S | N) : Required if tipo_desplazamiento_3.tipo_actividad_residente = 1.
• actividad_empresas_otros_estados (S | N) : Required if tipo_desplazamiento_3.actividad_25_porciento_espana = S.
• tipo_contratacion_menos_25 (integer) : Worker's type of engagement (when they do not carry out at least 25% of the activity in Spain). Required if tipo_desplazamiento_3.actividad_25_porciento_espana = N. Possible values:
  • 1: One company based in Spain.
  • 2: Two or more companies based in Spain.
  • 3: Two or more companies, at least two of them based in Member States other than Spain.
• opcion_desplazamiento (S | N) : Do the company's place of activity and the worker's place of residence coincide at the same location? Mandatory.

Sub-object tipo_desplazamiento_4 (civil servant, air crew or special maritime scheme)

Required when tipo_desplazamiento = 4.

• tipo_funcionario_mar_aereo (integer) : Worker category. Mandatory. Possible values:
  • 1: Civil servant.
  • 2: Air crew.
  • 3: Special Maritime Scheme (on board a vessel).
• reside_espana_salario_empresa_espanola (S | N) : Required if tipo_desplazamiento_4.tipo_funcionario_mar_aereo = 3. Does the worker reside in Spain and is the salary paid by a Spanish company?

Example — tipo_desplazamiento = 1 with opcion_actividad = 2

{
  "test": 1,
  "regimen": "0111",
  "ccc": "12345678901",
  "dni": "12345678Z",
  "nss": "123456789012",
  "tipo_desplazamiento": 1,
  "desde": "2026-06-10",
  "hasta": "2026-06-30",
  "paises": ["056"],
  "tipo_desplazamiento_1": {
    "vinculacion_directa_empresa_espanola": "S",
    "sujeto_solo_seguridad_espanola": "S",
    "enviado_por_empresa_o_teletrabajo": "S",
    "opcion_actividad": 2,
    "sustitucion_persona_desplazada": "N",
    "residente_espana_contratado_temporal": "S"
  }
}

Example — tipo_desplazamiento = 1 with opcion_actividad = 1

{
  "test": 1,
  "regimen": "0111",
  "ccc": "12345678901",
  "dni": "12345678Z",
  "nss": "123456789012",
  "tipo_desplazamiento": 1,
  "desde": "2026-06-10",
  "hasta": "2026-06-30",
  "paises": ["056"],
  "tipo_desplazamiento_1": {
    "vinculacion_directa_empresa_espanola": "S",
    "sujeto_solo_seguridad_espanola": "S",
    "enviado_por_empresa_o_teletrabajo": "S",
    "opcion_actividad": 1,
    "lugar_actividad": {
      "denominacion": "Empresa destino BVBA",
      "nombre_via": "Rue de la Loi",
      "numero": "16",
      "poblacion": "Bruselas",
      "codigo_postal": "1040",
      "pais_destino": "056"
    },
    "sustitucion_persona_desplazada": "N"
  }
}

Example — tipo_desplazamiento = 3 (multiple countries)

{
  "test": 1,
  "regimen": "0111",
  "ccc": "12345678901",
  "dni": "12345678Z",
  "nss": "123456789012",
  "tipo_desplazamiento": 3,
  "desde": "2026-06-10",
  "hasta": "2026-06-30",
  "paises": [
    "276", "040", "056", "208", "724", "250", "348",
    "380", "442", "578", "528", "616", "620", "203",
    "642", "752"
  ],
  "tipo_desplazamiento_3": {
    "reside_en_espana": "S",
    "tipo_actividad_residente": 1,
    "actividad_25_porciento_espana": "S",
    "actividad_empresas_otros_estados": "N",
    "opcion_desplazamiento": "N"
  }
}

Successful response

The RED System returns the PDA1 as a PDF (base64-encoded) when the submission is accepted.

{
  "success": true,
  "message": "Con los datos introducidos se ha procedido a tramitar correctamente el desplazamiento y a generar el PDA1. Dicho documento estará a su disposición en un plazo de 24/48 horas a través de comunicación en SEDE ELECTRÓNICA.",
  "status": 200,
  "data": {
    "file": {
      "contentType": "application/pdf",
      "name": "document.pdf",
      "content": "base64"
    }
  }
}

Response 409 — A1 not generated but a supporting document is available

In some cases the RED System rejects the issuing of the PDA1 but still issues a downloadable posting supporting document. The most common case is error 4224 (the requested period fully or partially overlaps another posting already recorded): the A1 is not generated and it must be processed through the Electronic Office (form TA/300), but the RED System generates a supporting document that must be attached to that application.

In that case the endpoint responds with HTTP 409 Conflict:

• success: false.
• status: 409.
• message: the RED System messages joined by . # (includes code 4224 and the notice that a supporting document was generated).
• data.a1_generado: false — the PDA1 has not been issued.
• data.justificante_generado: true — a downloadable supporting document is available.
• data.file: the posting supporting document as a PDF (base64).

{
  "success": false,
  "message": "4224 El periodo coincide total o parcialmente con otro ya anotado. Con los datos introducidos por usted no es posible la obtención del PD A1 a través de este servicio RED. Tiene que presentar la solicitud través del servicio de SEDE ELECTRONICA: Trabajadores Desplazados Modelo TA/300. Para justificar la realización a través de SEDE ELECTRONICA, deberá adjuntar el justificante que se ha emitido.. # No se ha podido generar el A1.. # Justificante generado correctamente. Pulse el enlace para abrirlo.. # Se recomienda guardar el PDF antes de imprimirlo por si tiene problemas con la impresora.",
  "status": 409,
  "data": {
    "a1_generado": false,
    "justificante_generado": true,
    "file": {
      "contentType": "application/pdf",
      "name": "document.pdf",
      "content": "base64"
    }
  }
}

Response with RED System warnings

When the RED System responds with validation messages (warnings to the user), success will be false and message will join the warnings separated by . # .

{
  "success": false,
  "message": "El periodo solicitado solapa con otro desplazamiento ya tramitado. # Revise las fechas indicadas.",
  "status": 200,
  "data": []
}