Energetic particles are an essential element of solar flares: they carry up to 40% of the released energy and provide a link for fast energy transport to the lower corona and into interplanetary space. Consistent fluid and kinetic models are essential both for understanding the energy release in flares and for providing diagnostics of the physical conditions in flaring atmospheres. I will discuss recent advances in modelling of high-energy particle kinetics in solar flares. Particularly, I will focus on the forward modelling of various observables, from EUV and SXR thermal emission to HXR and microwave non-thermal radiation produced by energetic particles.