This study aimed to characterize digital platform-based work arrangements in regard to their degrees of flexibility and their effects on professional achievement, balance between pros and cons, and perception of risk. A survey was conducted with platform-based workers in Argentina, Brazil, Chile, Colombia, and Spain (e.g., transport, care and cleaning, content production, and house renting). Two thousand and forty-eight workers contacted through social networks and unions participated. Based on the factorial analysis, we propose a flexibility index covering five dimensions (contractual agreement, working hours, workplace, remuneration, and union ties). After controlling for covariates, the flexibility index was used in a regression to measure its effects on professional achievement, the balance of pros and cons, and risk perception. The digital workers with the highest flexibility scores worked in transportation and the trade of goods and services. Flexibility reduces professional achievement when the worker accesses platform jobs due to a lack of alternatives.