CryoSPARC

CryoSPARC is the dominant processing platform for single-particle cryo-EM, taking raw movies through to refined 3D structures. Its algorithms and interface substantially shortened the path from microscope to map, and it is free for academic use — which is much of why it took over.

What it does

The pipeline covers motion correction, CTF estimation, particle picking, 2D classification, ab initio reconstruction, heterogeneous and homogeneous refinement, and local refinement, through a browser-based interface with visual feedback at each step. Ab initio reconstruction without a starting model was a genuine advance, and the heterogeneity tools handle the conformational mixtures that real samples contain.

Strengths

• Free for academic use, including the full pipeline.
• Fast GPU-accelerated algorithms with strong ab initio reconstruction.
• Browser interface with visual feedback at every stage.
• Serious tools for conformational and compositional heterogeneity.

Limitations

It is closed source, so the algorithms cannot be inspected and commercial use requires a licence — the reason RELION retains a committed following. It needs significant GPU and storage infrastructure. The interface makes it easy to produce a map, which is not the same as producing a correct one: overfitting and misassigned symmetry remain easy to achieve and hard to notice.