Before any company paperwork you need your tax ID. For foreigners, the starting point is the NIE (Foreigner Identity Number) and, if you'll be self-employed or a director, registration with the tax office and Social Security.

• —NIE — essential to open an account, sign and register.
• —Spanish bank account — to pay taxes and contributions.
• —Digital certificate — lets you do almost everything online.

The two most common routes:

• —Self-employed (autónomo) — quick and cheap to set up; ideal to start invoicing soon.
• —Limited company (S.L.) — more structure and limited liability; for projects with partners or investment.

Many people start as self-employed and form an S.L. as the project grows. An advisor (gestoría) saves time and avoids mistakes here.

As a guide: the NIE can take a few weeks depending on the consulate or appointment; self-employed registration is almost immediate once you have a NIE and certificate; forming an S.L. has more steps (company name, deed before a notary, registration at the Companies Registry) and usually takes a few weeks. Confirm current requirements with a gestoría, as details change.