This article presents fragments of the life of Duarte José Martins da Costa, a sailor whose experiences of enslavement and freedom were at the crossroads of the slave trade between West and Central-West Africa and Brazil. Through his trajectory, we examine the Atlantic connections between small businesses, seafarers, captive brokers; freed, enslaved, and free people; Europeans, Americans, Africans; whites, blacks, and “mixed race” people who constituted what we call the “small network” of the slave trade and who were also responsible for its breadth illegal in nineteenth-century Brazil.O presente artigo recupera fragmentos da vida do marinheiro Duarte José Martins da Costa, cujas experiências de escravidão e de liberdade estiveram nas encruzilhadas do comércio negreiro entre as costas ocidental e centro-ocidental da África e a do Brasil. Por meio de sua trajetória, cotejamos as conexões atlânticas que envolveram negociantes de pequeno porte, marítimos, agenciadores de cativos; libertos, escravizados, livres; europeus, americanos, africanos; brancos, negros e “mestiços”, os quais compõem o que denominamos de “rede miúda” do tráfico negreiro também responsável pela amplitude do comércio ilegal do Brasil do século XIX.