<p class="p1">goSPL (Global Scalable Paleo Landscape Evolution) is an open-source, parallel, finite-volume landscape evolution model designed to simulate the co-evolution of topography, drainage and sedimentary basins from catchment to planetary scale over geological time. Here, I present the new capabilities which extend the model from a fluvial–hillslope–marine sediment-routing engine into a coupled surface-process, near-surface-hydrology and weathering-geochemistry framework. The principal additions are (i) an implicit Dupuit–Boussinesq water table and a generic capillary-fringe duricrust that armours erodibility (forming either in situ or, with a groundwater-discharge gate, by lateral accumulation confined to valley discharge zones) and is archived in the stratigraphic record; (ii) a mass-conservative <em>solute geochemistry</em> module in which one or more lumped weathering tracers are dissolved, transported along the groundwater flux, precipitated as crust and routed down the river network to the ocean, with per-species typing, source provenance, spatially variable (lithology-controlled) weatherability and optional in-transit and marine coupling; (iii) a soil/regolith model; (iv) a mesh-native orographic-rain solver; (v) a diagnostic glacial-erosion model; and (vi) a parallel finite-volume flexural isostasy solver for planar meshes. All components are opt-in and are formulated as implicit or steady solves on a distributed PETSc DMPlex mesh, with solver choices (Krylov method, preconditioner, iteration scheme) driven by the conditioning of each operator. I describe the governing equations and the numerical and design choices behind each component, the YAML-based experiment configuration, the analytical-benchmark and regression test suite, and strong-scaling measurements on global production meshes of up to 23.7 million nodes. Finally I summarise the online documentation, the conda/PyPI/Docker distributions, the application interface and post-processing tools, and a suite of fifteen generic examples spanning regional and global scales. goSPL is distributed under the GNU GPL v3 licence.