Check their experience with Spanish Social Security (TGSS) filings. Spain requires monthly submissions to the Tesorería General de la Seguridad Social. The employer pays contributions during the following month and answers for both its own share and the amount withheld from the employee, so a provider's mistake is still your liability. Ask providers how they handle the Sistema RED and their error rate with TGSS submissions.
Verify they manage Spain's 14-payment salary structure correctly. Employees are entitled to two extra payments a year (pagas extraordinarias), one at Christmas and one at the time set by the collective agreement, which can also spread them across the 12 monthly payments. Your provider has to follow your agreement, calculate the extras correctly and withhold tax and social security on each payment.
Confirm they keep up with income tax withholding changes. Final income tax can involve the scale of the employee's autonomous community, and the Agencia Tributaria updates its withholding procedure during the year. The 2026 version took effect on 10 September. Ask how the provider makes sure each payment uses the version that applies on that date.
Ask about their Agencia Tributaria (AEAT) compliance process. The Spanish tax authority requires Model 111 filings for IRPF withholdings and an annual Model 190 summary. For ordinary filers Model 111 is quarterly, due within the first 20 calendar days after the quarter ends, but the frequency depends on your tax category, so confirm yours with the provider. They should file these automatically and send you the confirmation receipts.
Check how they handle pay above the contribution ceiling. In 2026 the standard employer rate for an ordinary permanent hire is 30.65% before occupational injury insurance, and the employee rate is 6.50%. Pay above €5,101.21 a month now carries a solidarity charge in three bands, paid by both employer and employee. A provider that still treats the ceiling as a hard cap will get contributions on senior salaries wrong.
Evaluate their payslip language capabilities. Spanish law requires payslips (nóminas) in Spanish with specific mandatory fields. Check that providers generate legally compliant nóminas, not just translated versions of generic templates.
Test their response time during Spanish business hours. If your provider operates from outside Spain, confirm they offer support during Spanish working hours, especially around month-end when payroll questions arise.
Pro tip: Ask how they handle Spain's strict electronic certificate requirements. Most interactions with TGSS and AEAT require digital certificates, and providers should manage these on your behalf without requiring you to obtain Spanish certificates yourself.