Currently, most research on basic income preferences is survey-based, relying on questions which ask for the degree of support for one particular definition of basic income. While this approach enables to detect sociodemographic variables associated to support for basic income as well as cross-national differences, existing work cannot explain how different policy design features shape support for basic income policy. The aim of this paper is to advance the knowledge on how policy characteristics shape support for basic income policy, through applying a conjoint experiment to measure support for different basic income related proposals. Conjoint experiments are being widely used to measure preferences in a range of multi-dimensional issues such as candidate preferences, attitudes towards immigration, and support for different policies such as unemployment or international bailouts. In this conjoint design, we present respondents two policy proposals that vary in six dimensions: universality, conditionality (behavioral and means-test), unit of recipient, quantity and funding mechanisms. We force respondents to choose between two policy alternatives that vary in the attributes presented within each dimension, which enables us to understand the trade-offs faced by each respondent in selecting different policy options. We administer this experiment to a nationally-representative sample of Spanish and Finnish individuals (2000 in total), during the month of March and April 2019.