  Josephson Traveling Wave Parametric Amplifiers (JTWPAs) are largely exploited
in quantum technologies for their broadband and low noise performance in the
microwave regime. When one or more microwave tones are applied at the input,
such devices show a complex wave-mixing response due to their intrinsic
nonlinear nature. Numerical simulations of the JTWPAs nonlinear behaviour
provide useful insights not only for the design of such devices, but also for
the interpretation and validation of the experimental results. Here we present
and discuss a comparative analysis of different open-source tools which can be
used for JTWPAs numerical simulations. We focus on two tools for transient
simulations, WRSPICE and PSCAN2, and on one tool for direct simulation of the
frequency domain behaviour, JosephsonCircuit.jl. We describe the working
principle of these three tools and test them considering as a benchmark a JTWPA
based on SNAILs (Superconducting Nonlinear Asymmetric Inductive eLement) with
realistic experimental parameters. Our results can serve as a guide for
numerical simulations of JTWPAs with open-source tools, highlighting advantages
and disadvantages depending on the simulation tasks.
