Odoo, SII and Form 303: Spanish accounting without headaches
If you run your company with Odoo and operate in Spain, sooner or later the usual acronyms show up: SII, Form 303, Form 347. The good news is that Odoo is ready to cover these obligations. On this page we explain, without jargon, how each piece fits together and where your accounting firm comes in.
Vendor bill in Odoo accounting · Nextdoo, Odoo Silver Partner
What the SII is and how Odoo handles it
The SII (Immediate Supply of Information) requires certain companies to electronically send the details of their issued and received invoices to the AEAT electronic office within a few days. Not all SMEs are required to comply: it mainly affects large companies, VAT groups and those who file monthly. Your accounting firm will confirm whether this applies to you.
When we talk about Odoo, the SII, Form 303 and Form 347 make up the Spanish accounting block that the system is able to prepare. With the Spanish localization enabled, Odoo records every invoice with the data the SII needs and generates the submissions to the tax authorities. The goal is that you don't have to copy invoice by invoice by hand into another portal.
VAT Form 303 within Odoo
Form 303 is the quarterly (or monthly) VAT self-assessment. With Odoo properly configured, every sales and purchase invoice carries its correct VAT rate and accounting account, so the system accumulates the taxable bases and amounts throughout the period. When you close the quarter, you get a report with the Form 303 boxes already calculated.
This is where the Odoo–SII–Form 303 combination makes sense: the same entries that feed the SII submission are the ones that later reconcile with your VAT return. Less duplicated work and less risk of mismatches. Even so, the final figure is always reviewed and filed by your accounting firm or tax advisor before submitting it.
Form 347 and transactions with third parties
Form 347 is the annual informative return of transactions with third parties exceeding €3,005.06 per year with a single customer or vendor. It's a form that often raises questions because it requires having all contacts properly identified and their transactions correctly totaled.
Odoo makes this task easier because all invoicing is already recorded by contact. The system can group transactions by customer and vendor and flag who exceeds the threshold, leaving the information ready to review. As with the other forms, the final judgment and the filing remain in the hands of your accounting firm.
Bank reconciliation: balancing without wasting hours
A large share of accounting errors don't come from taxes, but from not having the bank reconciled. Odoo lets you import bank transactions (by file or through a connection) and reconcile them with the recorded invoices and payments. The system proposes automatic matches and you only confirm or adjust the ones that don't fit.
Reconciliation kept up to date means that, when the time comes for Form 303 or the year-end close, the accounts reflect the reality of the cash. That reduces surprises and makes the review with your accounting firm faster and cheaper, because there's no need to chase down mismatched entries at the last minute.
VeriFactu: the change coming to invoicing
VeriFactu is the new framework for verifiable invoicing in Spain, tied to the Anti-Fraud Law, which requires invoicing systems to record invoices in an unalterable and traceable way. It does not replace the SII or the VAT forms: it is a layer that affects how invoices are issued and stored.
Odoo is working on its adaptation to VeriFactu within the Spanish localization. If you want to understand in detail what it means for your business and how to prepare, we cover it in depth on our page about VeriFactu with Odoo. Our recommendation is not to leave it until the last minute and to plan the setup well in advance.
Where Nextdoo comes in (and where your accounting firm does)
At Nextdoo, as an Official Odoo Partner focused on retail and SMEs, we take care of making the technical side work: enabling the Spanish localization, configuring taxes and accounts, getting the SII submissions and the Form 303 and 347 reports operational, and setting up bank reconciliation. You can see the full scope on our Odoo accounting page.
What we don't do is replace your tax advisor: the accounting criteria, the interpretation of the rules and the official filing of the forms remain your accounting firm's job. We prepare the system so that this validation is straightforward. A well-executed implementation usually falls in the range of a few thousand euros depending on the size of the company (reference estimate, non-binding). If you want a specific quote, let's talk in a no-obligation Odoo consulting session.
Frequently asked questions
Does Odoo file Form 303 directly with the tax authorities?
Odoo calculates the Form 303 boxes from your invoices and leaves the report ready. In most cases, the review and the official filing are handled by your accounting firm or tax advisor, who validates the amounts before sending them to the AEAT.
Is my SME required to comply with the SII?
The SII mainly affects large companies, VAT groups and those who file VAT monthly. Many SMEs are not required to comply and file their forms quarterly. Check with your accounting firm, because it depends on your turnover and your specific regime.
Does Odoo generate Form 347 automatically?
Odoo groups transactions by customer and vendor and flags who exceeds the annual threshold of €3,005.06, leaving the information ready for Form 347. The final judgment and the filing remain in the hands of your accounting firm, which reviews the data before declaring it.
Is Odoo ready for VeriFactu?
Odoo is adapting its Spanish localization to VeriFactu, the verifiable invoicing framework of the Anti-Fraud Law. It does not replace the SII or Form 303. The advisable thing is to plan the setup well in advance; we explain it on our dedicated page about VeriFactu with Odoo.
Is bank reconciliation in Odoo automatic?
Odoo imports your bank transactions and proposes automatic matches with your invoices and payments. You confirm or adjust whatever doesn't fit. It's not total magic, but it greatly reduces manual work and helps the close and Form 303 balance without surprises.
Related resources
Official information: AEAT — official information.