Credits

Credits is the standard universal in-game currency.

They are obtained from Taxation on the Colonies' Economy after Corruption is applied, from Trade (selling commodities or services) or Diplomatic Agreements (war reparations, tributes, etc., as well as gifts from your patron civilization).

They are used to cover Colony Upkeep & Fleet Upkeep costs, to fund Research, Exploration and Espionage, to increase Construction and/or Production Capacities (under certain government types), in Trade (buying commodities or services) & Diplomatic Agreements (patronage and other) and as contribution to Alliance Projects.