Biological Small Angle X-ray Solution Scattering (BioSAXS) informs on the size and shape of biomolecules in solution, offering valuable insights into their dynamics and behaviors under native, physiological conditions. Owing to the experimental ease and flexibility, BioSAXS has garnered numerous applications, including studies on flexibility, disorder, protein folding, conformational changes, and oligomeric states; validation of structural models; and screening sample conditions for cryo-EM and crystallography. Moreover, BioSAXS has increasingly been utilized in research on liquid-liquid phase separation (LLPS), intrinsically disordered proteins (IDPs), and lipid nanoparticles (LNPs).