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Free forever up to 30 documents a year · No card

Invoice, keep the books, and reach the 20th with your taxes already worked out

Cairos is the Spanish ERP for autónomos (registered self-employed workers), small businesses and non-profit organisations. Invoices with VeriFactu, expenses, inventory, cash flow, and the AEAT tax forms already worked out from what you have entered over the quarter.

VeriFactu included on every planBuilt and supported in SpainNo lock-in
erp.cairos.es
General
Dashboard
Invoices
Quotes
Contacts
Expenses
Products
Accounting
18.420 €
Invoiced this month
6.180 €
Awaiting payment
3.257 €
VAT for the quarter
12
Due this week
F-2026/0184Talleres Miralles SL1.815,00 €Paid
F-2026/0183Grupo Bonaire3.146,00 €Sent
F-2026/0182Ajuntament de Girona8.470,00 €Overdue
F-2026/0181Nuria Sastre484,00 €Paid
Everything you keep in four different places today
Invoicing
Invoices, quotes, delivery notes and payments
Accounting
Books, journal entries and annual accounts
Taxes
303, 390, 347, 349, 111, 130, 720…
Operations
Inventory, projects and CRM
The problem

The quarter does not get complicated because of the accounting.
It gets complicated because of the loose data.

Invoices in one program, expenses in a folder, the bank in another tab and the spreadsheet only you understand. When the 20th comes round — the day the quarterly returns are due — it all has to be pulled together by hand, and that is where the hours go and the mistakes appear.

How it is normally done

  • Invoices in one program, expenses in another and the VAT in a spreadsheet.
  • Modelo 303 gets worked out by hand, and nobody knows where each box came from.
  • Deductible expenses turn up in March, when they are no longer any use for the quarter.
  • Nobody notices that invoicing a German client means you have to file a modelo 036.
  • If your accountant asks about an invoice from two years ago, you have to go and find it.
  • And now VeriFactu on top of it.

With Cairos

  • One single database: what you invoice and what you spend feed the same set of books.
  • Modelo 303 comes out calculated, showing which invoice goes into each box.
  • Expenses go in as they happen, and the result for the quarter is always up to date.
  • The ERP flags the modelo 036, because it is the only thing that knows you have invoiced abroad.
  • Everything is stored, searchable and exportable, with the PDF attached.
  • VeriFactu included from day one, on the free plan too.
What is included

One module for each thing your business does

You switch on only the ones you need. An autónomo invoicing for services sees four screens; a garage with a warehouse sees its own. Nobody has to learn a whole program in order to issue an invoice.

Required by law

VeriFactu is not a paid feature. It is the law.

The Regulation on computerised invoicing systems requires every invoice to leave behind a record that cannot be altered and that is chained to the one before it. Cairos does this on its own, on every plan, the free one included.

  • An issue record and a cancellation record for every document
  • Chained SHA-256 hash: if someone touches an old invoice, it shows
  • QR code and the compulsory legend on the PDF
  • Submission to the Spanish Tax Agency in VERI*FACTU mode, with your own certificate

What VeriFactu is and when it becomes compulsory

An invoicing system that complies with VeriFactu
hash 7f3c1a…d904
previous 21b8e0…4c17
issued 2026-08-24 10:14:03
status registered with the AEAT
Inside

This is what the quarter looks like when it is up to date

This is not a mock-up: it is the program's own screen. The dashboard tells you what you have invoiced, what you are owed and what is coming at you, before the 20th arrives.

The Cairos dashboard: sales and expenses for the financial year, the result, the VAT owed and the month-by-month chart
The home dashboard: what you have invoiced, your expenses, the result for the financial year, the VAT you owe, and how this year is going against last.

Look inside without committing to anything

The free account asks for no card and does not expire. Issue a couple of test invoices and you will see how the program behaves with your own data.

Get started

From nothing to your first invoice in ten minutes

No installation, no consultant, and no sales call before you can try it.

1

Create the account

With an email address. No card, no lock-in.

2

Enter your tax details

NIF, address and the series you number with. Two minutes.

3

Bring what you already have

Contacts and products, typed in as you go. Importing from CSV or Excel is on the way.

4

Invoice

With its VeriFactu QR code and its chained record from the very first one.

12
tax forms worked out for you
0 €
is what the free plan costs
8 €
per month, billed annually, with unlimited documents
100 %
built and supported in Spain
Who is behind it

A small team, in Spain, that picks up the phone

Cairos is not a fund's portfolio product, nor anybody's Spanish subsidiary. We build it here, we maintain it here, and we handle support ourselves, in Spanish and without escalation tiers.

There is a bad side to that and it is worth saying: we are new, we do not have twenty integrations or ten years behind us. And a good side: when you write in, the person who answers has written the code.

  • Servers in the European Union, backed up daily.
  • Your data exports whole, from your own account.
  • No lock-in: if it is not working, you leave and you take everything with you.
The Cairos team at work in the office
The team that writes the program and answers the email.

Frequently asked questions

Management software for Spanish autónomos and small businesses. You issue invoices and quotes, record expenses, keep the inventory, track payments in and out, and produce the AEAT tax forms — modelo 303, 390, 347, 111, 130 and the rest — all from the same place, without moving data from one program to another. The forms come out calculated and broken down box by box; filing them still happens at the AEAT's electronic office, with your own certificate.
Yes, and it is included on every plan, the free one too. Every invoice generates its billing record, chained with a SHA-256 hash, and its QR code. We set it out in detail on the VeriFactu page: charging you to meet a legal obligation strikes us as indefensible.
Yes: 30 documents a year, one user and one company, no card and no expiry date. The limit is on volume, not on features, so that you can judge the program by what it does rather than by what it hides from you.
Importing contacts, products, invoices and expenses from CSV or Excel is built but not yet open: it comes with the Autónomo plan as soon as it is, at no extra cost. Migration done by us belongs to the bespoke plan. It is all explained under how to migrate your data.
Yes, and it is one of the things almost no program does. Cairos has a members' register and direct debit fees with a SEPA file, donations with modelo 182, the application of a cooperative's surplus under its regional law, and the VAT treatment of a club's membership fees. Start with the legal structures.
On servers inside the European Union, backed up daily. It is neither sold nor handed to anyone. We set it out in detail under security and data.
Cairos does not replace your accountant: it hands them figures that add up, on time. In fact plenty of accountancy firms use it with their clients, because it puts an end to the emails with the usual spreadsheet attached, and the quarter comes straight out of the program.

Start invoicing today

Free plan forever, no card needed. And if one day it stops working for you, your data leaves in one click: it is yours.

No lock-in · Support in Spanish · Your data, in the European Union

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