A widely-used software for simulating electrochemical interfaces is VASPsol, which integrates an implicit solvation model that describes the effect of electrostatics via the linearized Poisson-Boltzmann equation, cavitation, and dispersion on the interaction between a solute and solvent; and the more recent VASPsol++, which extends the former by including charging schemes up to modified Poisson-Boltzmann level as well as non-linear and non-local cavity definitions. A different method for simulating a grand canonical ensemble at the interface is integrated into the jDFTx software; here, the number of electrons is adjusted given a fixed chemical potential, target-µ. Another approach for including electrode potential is the constant-potential hybrid solvation dynamic model, in which the region of the supercell above the explicit atoms is filled with an implicit solution. This method is implemented in VASP and updates charge and capacitance at each step to match the target potential. Finally, the Solvated Jellium Method (SJM), the method we adopted in this work, is based on a homogeneous countercharge region embedded in an implicit solvent and allows for first-principles calculations of electrochemical systems at constant electrode-potential. It has been implemented in the open-source code GPAW and has been applied in various mechanistic studies, such as for electrochemical hydrogen evolution and CO 2 reduction. Applying these available constant potential schemes is in principle straightforward. However, combined with MD, strict enforcement of constant potential incorrectly suppresses thermal fluctuations in charge and potential at the atomic scale. It considers only a dissipative process of the controlling mechanism. Using the fluctuation-dissipation theorem (FDT), it is possible to include fluctuations 42 in charge and potential at the nano-scale by introducing an equation of motion for the charge of the electrode. A recent implementation within AIMD employs the proprietary VASP code to study the properties of nano-confined water. In this work, we combine the fluctuation-dissipation theorem with the solvated jellium model to perform first-principles molecular dynamics simulations at constant average charge and potential in GPAW. Our implementation of this FDT-SJM method into GPAW enables simulations in the NVTΦ ensemble and facilitates simulations of electrochemical environments where the potential can be varied by adjusting the charge of the systems. This also allows for the estimation of the minimal EDL capacitance C edl and potential of zero charge (PZC) to connect the simulation results to experimentally measurable quantities.