Self-employment visa (cuenta propia): apply for the initial residence-and-work authorization with a viable business plan, proof of sufficient funds and any licences your activity needs — the authorization comes before the consulate visa

Spain will let you move to work for yourself, but it wants to see a real business first: a viable plan, money to fund it, and whatever licences the activity needs. The authorization is assessed before your consulate visa, so the plan and evidence come together at the very start. A gestor who has shepherded these files knows what "viable" reads like to the reviewing office — money well spent here.