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Introduction

The Spanish Tax Agency (AEAT) requires that companies formally authorize Invopop to issue invoices on their behalf. To comply with this regulation, the supplier’s legal representative must sign an agreement granting Invopop the necessary consent to generate and manage invoices in their name. This signed authorization ensures that all invoicing activities carried out by Invopop are legally valid and recognized by the AEAT. For this process, the supplier can sign the agreement PDF with a valid digital certificate, such as one issued by the FNMT, or a handwritten signature with a company stamp (sello de empresa), in which case the user must provide a valid ID such as DNI, NIE or passport. In the case of self-employed individuals (autónomos) a company stamp is not required. This guide will walk you through the process of creating the workflows necessary to onboard yourself and/or your suppliers (in a white-label setup), the process of completing the supplier onboarding wizard, explaining the approval process and what to do in case of rejection.

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Set-up

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Getting started

1

Connect the Spain app

  1. Go to Configuration → Apps in the Console.
  2. Find Spain in the app list.
  3. Click Connect to activate the app.
After connecting, you’ll see SII listed in the Enabled Apps section.
2

Create a supplier registration workflow

Create a new workflow in your workspace for registering suppliers. You should start with the template below:

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Create a supplier entry

Whether you issue invoices on behalf of third parties (white label) or under your own name, the process is essentially the same. However, we divide the use case here for clarity:
  • Upload and register third-parties
  • Upload and register your company
1

Upload a supplier

Use the Create an entry endpoint to upload a new supplier. Include a party (you can copy the example below) object in the data field. The required fields are name and tax_id while address and email are recommended. Set folder to suppliers to have the party appear in this section.
SII supplier example
{
  "$schema": "https://gobl.org/draft-0/org/party",
  "name": "Invopop S.L.",
  "tax_id": {
    "country": "ES",
    "code": "B85905495"
  },
  "addresses": [
    {
      "num": "42",
      "street": "Calle Pradillo",
      "locality": "Madrid",
      "region": "Madrid",
      "code": "28002",
      "country": "ES"
    }
  ],
  "emails": [
    {
      "addr": "[email protected]"
    }
  ]
}
You should see the supplier in the Suppliers section with status Empty after creating the entry.
Upload supplier to Invopop

Upload supplier to Invopop

2

Send the supplier to the registration workflow

Send the supplier to the registration workflow using the Create a job endpoint. Use:
  • The Silo Entry ID of the supplier you uploaded on the previous step
  • The Supplier Registration Workflow ID from the Setup section
The supplier’s status will change to Processing while waiting for supplier registration and verification. Once these steps are completed successfully, the supplier’s status will change to Registered. If not successful because the supplier did not complete the process or their documentation was rejected, the status will change to Error, and you can inspect the job history of this document to see the reason.
Supplier registered

Supplier registered successfully

If a supplier’s agreement documentation is rejected and you need to onboard them again, follow the instructions in what happens if a supplier validation is rejected

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How SII supplier registration works

The process is best explained looking at the workflow steps:
Supplier Registration Workflow

Supplier Registration Workflow

  1. Register supplier will generate a unique URL and add it into a url key value within the meta property. You would add a webhook after this step to notify the supplier.
  2. Set State to Processing labels the silo entry so you know it’s in process of registration.
  3. Wait for supplier registration waits for the supplier to upload the required documents (signed agreement and ID). The supplier will be entitled to issue invoices through SII immediately after the documents are uploaded.
  4. Set State to Registered labels the silo entry so you know registration is complete.
  5. Wait for supplier approval In live environments, Invopop will review the documents provided by the supplier in less than 72 hours. In sandbox, you can configure the workflow step to accept or reject providers. Open rejection the workflow will error with a KO and the reason for rejection can be reviewed in the Supplier or in the executed job. The supplier’s invoice issuing entitlement will be revoked immediately.
In sandbox “Wait for supplier approval” can be configured to accept or reject suppliers. Re-running the workflow will not change the approval outcome, the supplier must be unregistered first.

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Register a Supplier

Suppliers need to provide the following documents for Invopop to issue invoices on their behalf:
  1. A signed direct representation agreement. If the supplier is a self-employed individual (autónomo), stamping is unnecessary.
  2. A copy of signatory’s fiscal ID (DNI/NIE or passport in the case of non-residents) if the agreement is not signed with a valid digital certificate such as one from the FNMT.
These documents can be collected through a multi-step web form (wizard) which enabled through the Supplier registration workflow created during setup.

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Onboard suppliers through the supplier registration wizard

The supplier registration wizard walks you (or your customers) through the necessary legal requirements to issue SII invoices. Each issuer must submit a signed representation agreement between Invopop and the issuer, along with documentation proving their legal authority to enter into such an agreement. Once you run the Supplier Registration Workflow, you will find the link_url in the meta property of the supplier entry. Here is an example API response:
In console, you will find the link in the Meta tab in the right sidebar of the supplier’s entry. This wizard can be embedded as an iframe to onboard your customers without leaving your product or platform.
1

Welcome screen

Your customers will be met with the first page detailing the necessary documentation required for the process.
2

Information verification

The user can edit personal or company information. If the user is a self-employed individual, only the company information block will appear. Such individuals should enter their real name in the “Nombre” field, as this is matched by the AEAT against their tax id.
3

Download agreement

On the following page, the issuer can download and sign their agreement. The details from the previous page will auto-populate into the contract.The issuer (you, or your customer) will require the following:Please be advised that any certificate that is not issued by the FNMT is not valid. Self-signed and certificates issued by other authorities are not considered valid.
4

Upload signed agreement

Issuers select the type of signature they used and upload their document. If digital signature is selected, the following step will be skipped as a signature through a FNMT digital certificate counts as a proof of identification.
5

Upload ID

The legal representative uploads a scan or clear photo of their ID in a valid image format (JPG or PNG). The ID should ideally be a DNI/NIE, as passports are only used when the person is not entitled to have one.Both the front and reverse of the ID should be submitted here. If the ID is a passport (only valid for non-Spanish residents who are representatives of a company), they can upload the main page of their passport both times.
6

Review details

This page provides a summary of information so the user can verify they have submitted the correct data. Any corrections can be easily made through the edit function.
7

Confirmation screen

Supplier registration wizard
A green checkmark will indicate success, and the supplier will await approval from our team, which will be made in less than 72 hours.

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Unregister a supplier

Unregistering a supplier is essentially revoking their invoice issuing privileges. You might need to unregister an entity because the supplier is no longer your client, because their agreement documentation was rejected, or because of a change in their Tax ID. To do so, use the following workflow template:
There is no official certification for SII from the AEAT (the Spanish tax agency). Instead, each developer, company, or provider that implements an invoicing software must provide an electronically signed declaration where they certify that their system meets all the requirements established in the regulations. This document is binding and must be kept available for the Tax Authority.The AEAT requires that this declaration be available and always visible within the system itself, and it must include certain control elements such as the installation number, issuer data, software version, and system ID.If you are a white label user of Invopop (you issue invoices in the name of third parties), you are required to display a link to this “declaración responsable” in your software. Here is the template from the AEAT, and our own for your reference: Declaración responsable SII - Invopop. Some of our customers have asked us if it is necessary to mention Invopop in their declaración responable. It is not required, but we appreciate it.

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FAQ

We reject agreements when:
  • The uploaded document is not signed (they upload the unsigned template).
  • Users upload a handwritten signature without and ID.
  • The electronic signature is made with an FNMT certificate.
  • The agreement is missing a date or location.
  • The name is entered as an email address.
The job will state the reason for rejection.
A KO will be triggered and the supplier will be labelled with the Error state. We currently recommend sending a reminder to the supplier through a webhook.The registration link will not expire and the entity will still be able to upload their registration documents which will be validated. Should you choose to run this workflow again using this supplier, the supplier will be accepted or rejected immediately because the required documentation has already been provided and validated.
If the uploaded agreement documents were rejected, a KO will be triggered and the supplier will be labelled with the Error state. We currently recommend sending a notification to the supplier through a webhook within the Error Handling section.Afterwards, if you wish to re-register the supplier with new documents, you must:
  1. Unregister the supplier using the Unregister Supplier workflow.
  2. Re-run the Register supplier workflow.
This will restart the entire registration process. When uploading documents, the previously submitted agreement will appear selected by default. Simply choose a new file and click Continue to override the old one. See the image below for reference:
Overriding the previously submitted agreement

Overriding the previously submitted agreement

In order to complete the representation agreement you will need to provide the following information:

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Company

  1. Name
  2. CIF
  3. Address
  1. Full name
  2. Government ID type and number
  3. Address
If the entity is an self-employed individual (autónomo), only the information requested in in the Legal representative section is required.
The supplier can add their electronic signature to the PDF document (instructions), or sign with a handwritten signature (we recommend using Adobe’s online service.
Individual documents are limited to a maximum size of 10MB. Uploads exceeding this size will result in an error.

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