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The very first light captured by the James Webb Space Telescope (JWST)revealed a population of galaxies at very high redshifts more massive thanexpected in the canonical $\Lambda$CDM model of structure formation. Barring,among others, a systematic origin of the issue, in this paper, we testalternative cosmological perturbation histories. We argue that models with alarger matter component $\Omega_m$ and/or a larger scalar spectral index $n_s$can substantially improve the fit to JWST measurements. In this regard,phenomenological extensions related to the dark energy sector of the theory areappealing alternatives, with Early Dark Energy emerging as an excellentcandidate to explain (at least in part) the unexpected JWST preference forlarger stellar mass densities. Conversely, Interacting Dark Energy models,despite producing higher values of matter clustering parameters such as$\sigma_8$, are generally disfavored by JWST measurements. This is due to theenergy-momentum flow from the dark matter to the dark energy sector, implying asmaller matter energy density. Upcoming observations may either strengthen theevidence or falsify some of these appealing phenomenological alternatives tothe simplest $\Lambda$CDM picture.

A double take on early and interacting dark energy from JWST