I will introduce two online resources: the L-functions and modular forms database (lmfdb.org) and MathBases (mathbases.org). The first is a large database in number theory, with 20+ collections ranging from modular forms to number fields, abstract groups to elliptic curves. The second brings together an index of mathematical databases with resources for mathematicians interested in creating their own. I will aim to draw lessons that are applicable to databases in homotopy theory. Bring a laptop so that you can explore during the talk!