If you use Factusol for invoicing and Contasol for accounting, you already know what this is about: every month-end, someone — you, your accounting firm or an administrator — has to re-enter in Contasol what is already in Factusol. Sales invoices, purchase invoices, credit notes. One by one. Or in bulk, with the risk of errors that entails. This is a classic rework problem that Software del Sol (now part of the TeamSystem group) has been solving for years with a native integration between both programs. This article explains how that integration works, what to configure before launching it and what to do when the business grows and needs more.
Why Factusol and Contasol are two separate programs
The question is legitimate: why not a single program that does everything? The answer is that invoicing and accounting follow different logic. Factusol is designed for the commercial cycle: quotes, orders, delivery notes, sales invoices, stock management and supplier purchases. Its typical user is the sales department or the self-employed business owner. Contasol, on the other hand, is a professional accounting engine: it handles the Spanish General Chart of Accounts, VAT and income tax returns, the Immediate Supply of Information (SII) for large companies and the generation of annual accounts. Its typical user is the company accountant or the external accounting firm.
Separating both functions makes sense when different profiles need access: the sales team does not need to see the accounting ledger, and the accountant should not touch the sales price lists. But that separation creates a boundary where data must cross. The native DELSOL integration solves exactly that boundary.
How the Factusol-to-Contasol export works
Factusol generates an interchange file in its own format (extension .fac or via direct export to the shared Contasol directory) containing the journal entries corresponding to the invoices issued and received. Contasol reads that file and imports them as entries in the journal, respecting the account coding you have configured.
The process has three main steps:
- Configure the account mapping in Factusol: specify which account in the chart of accounts corresponds to each VAT rate, to customers and suppliers, to sales income and to purchase expenses. This is done once, in the company settings inside Factusol.
- Export the period from Factusol: in the utilities or accounting integration menu, select the date range (for example, the current month) and generate the transfer file.
- Import in Contasol: from the Contasol import module, point to the generated file and the program creates the journal entries automatically. If any already exist for the same period, the system warns to prevent duplicates.
The result is that the journal entries for sales, purchases, output VAT and input VAT appear in Contasol without anyone having typed them manually. The accountant only needs to review, adjust if there is any exception (an accrual entry, a provision) and close the period.
Prior configuration: what needs to be in order
The integration works well when both programs are correctly set up. These are the critical points to check before activating it:
- Consistent chart of accounts: the chart of accounts used by Contasol must match the accounts assigned in Factusol. If in Factusol you have set account 4300000 for customers and in Contasol the customer is under 430, the entry may not balance or may create an unwanted new account.
- VAT rates properly defined: each VAT rate in Factusol (21%, 10%, 4%, exempt, intra-Community) must map to the corresponding VAT account in Contasol (477, 472, depending on output or input).
- Invoice series numbering: if you use multiple invoice series in Factusol (for example, series A for direct sales and series B for services), it is advisable to map each series to a different income account in Contasol so that the account-level analysis is meaningful.
- Shared directory or local network: if Factusol and Contasol run on different computers, the interchange directory must be accessible from both. In the cloud version (DELSOL 360) this is managed automatically.
Comparison: native integration vs. manual entry vs. DELSOL 360
| Method | Time per monthly close | Error risk | Additional cost | Best suited for |
|---|---|---|---|---|
| Manual entry in Contasol | 2-8 hours | High (typing errors, omissions) | Staff time only | Very low volumes (<30 invoices/month) |
| Native export Factusol → Contasol | 15-30 minutes | Low (automated process) | None (included in licences) | SMEs with local installation or internal network |
| DELSOL 360 (integrated cloud suite) | Real-time integration | Minimal (automatic synchronisation) | Cloud subscription (indicative: from ~21 EUR/user/month) | Remote teams, companies with external accounting firms |
| ERP with unified accounting module | No transfer needed (single system) | Minimal | Higher initial investment | Growing companies with broader requirements |
The native export is the most efficient option for most SMEs that already have Factusol and Contasol installed. It requires no additional investment and drastically reduces the time needed to close the books. DELSOL 360 is the logical next step when the team works remotely or when the accounting firm needs simultaneous access to the data.
Common errors and how to avoid them
In our experience implementing and supporting these solutions at Summum Sistemas, the three most recurring problems are:
1. Unmapped accounts generating entries to a catch-all account
When Factusol finds a VAT rate or an income account that has not been assigned in the integration configuration, it either dumps the amount to a generic account or the import fails altogether. The solution is to review the incident report generated by the Contasol import and adjust the mapping before re-running.
2. Importing the same period twice
If the first transfer had errors and a second run is launched without deleting the entries from the first, the amounts are duplicated. Contasol warns of this risk, but it is worth having a clear protocol: before re-importing, delete all entries for the period that came from Factusol.
3. Imbalances caused by VAT rounding
On invoices with multiple lines at different VAT rates, rounding can create penny differences between Factusol and Contasol. Correctly configuring the number of decimal places in both programs and keeping them consistent eliminates this problem.
Verifactu 2027: what changes in the integration
With the entry into force of Verifactu (legal entities from 1 January 2027, self-employed from 1 July 2027, pursuant to Royal Decree 1007/2023 and its subsequent amendment by RDL 15/2025), the invoicing system must generate verifiable invoicing records with chained hashes and submit them to the AEAT in real time or in batches.
Factusol is already adapted to Verifactu, which means the records it generates comply with the technical requirements established by the AEAT. It is important to clarify that there is no «homologation» or certified software list from the AEAT: the legal mechanism is the manufacturer's declaration of responsibility (pursuant to RD 1007/2023). Software del Sol, as the manufacturer, has assumed that declaration of responsibility for Factusol.
For the integration with Contasol, the main novelty of Verifactu is that invoicing records are no longer just an accounting entry: they carry traceability information (record number, digital fingerprint, date and time of issue) that must remain linked to the journal entry. The native integration between Factusol and Contasol also transfers this traceability data, so that the accountant has in Contasol not only the amount but also the Verifactu identifier for each invoice.
If your company has not yet assessed what Verifactu means for its invoicing software, now is a good time to do so: our Summum Sistemas team carries out compliance assessments and manages the update or migration depending on each company's situation.
When the Factusol-Contasol integration is not enough
The native export covers the standard commercial-accounting cycle perfectly. But there are scenarios where the business needs more:
- Project management or cost centres: if you need to allocate costs and income to projects, construction jobs or branches, the basic integration does not include that analytical dimension. Contasol does have an analytical accounting module, but it needs to be explicitly configured.
- Multiple warehouses or branches: Factusol manages multiple warehouses, but if each branch has its own accounting, the transfer flow becomes more complex. In that case, DELSOL 360 or a more comprehensive ERP solution such as Distrito K may be more appropriate.
- B2B electronic invoicing: the Spanish Ley Crea y Crece will shortly require structured electronic invoicing (FacturaE or Peppol format) between businesses. Factusol is progressively incorporating these capabilities, but it is worth staying up to date with releases.
- Integration with an online store or marketplace: if you generate orders from an e-commerce website and want them to enter Factusol directly without rework, that requires an additional integration that goes beyond the native connection with Contasol.
For these more complex cases, at Summum Sistemas, as an Official Partner of TeamSystem, we analyse the full picture and propose the most efficient architecture: that may be DELSOL 360, Distrito K for advanced distribution, or keeping Factusol+Contasol with specific custom integrations.
Steps to activate the integration today
If you already have Factusol and Contasol installed and are still entering invoices manually in Contasol, here is the road map to activate the native export:
- Update both programs to the latest version. The integration improves with each release and older versions may not be compatible with each other.
- Review the chart of accounts in Contasol and make sure the accounts you will need are created (customers, suppliers, output VAT, input VAT, sales by product type, purchases).
- Configure the accounting integration in Factusol: go into the company settings, find the accounting or Contasol integration section, and map each concept to its chart-of-accounts code.
- Run a test with a closed month (not the current month): export that period, import it in Contasol and compare the result with the entries you had entered manually. The differences will tell you what configuration needs adjusting.
- Document the process and train whoever will run it each month. The procedure is straightforward but must be followed (export before import, check the incident report).
Frequently asked questions
Can I export Factusol invoices to Contasol if I use old desktop versions?
The native integration has been available since relatively old versions of both programs, but the exact compatibility depends on the specific version numbers. Software del Sol publishes a compatibility matrix on its website. In general, if both programs are less than three years old, the integration works without issues. If either is older, we recommend updating: in addition to compatibility, current versions include the Verifactu adaptations that will be mandatory from 2027.
Does the export also work for supplier purchase invoices?
Yes. Factusol manages both sales invoices (issued to customers) and purchase invoices (received from suppliers). Both types can be exported to Contasol and generate the corresponding journal entries: for sales, the customer, income and output VAT entry; for purchases, the supplier, expense and input VAT entry.
What happens with credit notes or rectifying invoices?
Rectifying invoices (credit notes) are also included in the export and generate reverse entries in Contasol. It is essential that in Factusol they are correctly recorded as rectifying invoices and linked to the original invoice, so that the entry in Contasol accurately reflects the situation. A credit note incorrectly recorded as an ordinary invoice can create an imbalance in the VAT accounts.
Does it make sense to keep Factusol and Contasol separately or is it better to move to DELSOL 360?
It depends on the usage profile. If the invoice volume is manageable, the team works on the same local network and the accounting firm does not need remote access to the data, Factusol+Contasol with native export is a perfectly valid and cost-effective solution. DELSOL 360, the cloud suite that integrates Factusol, Contasol and Nominasol in real time, makes sense when there is remote working, multiple simultaneous users or when the accounting firm needs to view the data directly without waiting for the monthly transfer. The cost is somewhat higher, but it completely eliminates the friction between modules.