  We introduce CircuitQ, an open-source toolbox for the analysis of
superconducting circuits implemented in Python. It features the automated
construction of a symbolic Hamiltonian of the input circuit and a dynamic
numerical representation of the Hamiltonian with a variable basis choice.
Additional features include the estimation of the T1 lifetimes of the circuit
states under various noise mechanisms. We review previously established circuit
quantization methods and formulate them in a way that facilitates the software
implementation. The toolbox is then showcased by applying it to practically
relevant qubit circuits and comparing it to specialized circuit solvers. Our
circuit quantization is applicable to circuit inputs from a large design space,
and the software is open-sourced. We thereby add an important resource for the
design of new quantum circuits for quantum information processing applications.
