# EXESS by QDX

> EXESS is flagship quantum chemistry software by QDX. It compresses a year of compute into hours, performing ab initio quantum molecular dynamics simulations 1000x faster and larger than anything before. It generates high-accuracy quantum chemistry data orders-of-magnitude faster using GPU acceleration.

## About QDX

QDX is a computational chemistry company that integrates the world's fastest and largest-scale quantum mechanical simulation technology with supercomputing, artificial intelligence, and deep drug discovery expertise. We partner with leading pharmaceutical companies and academic institutions to advance the frontiers of computational chemistry and drug discovery. They provide access to their record-breaking quantum chemistry software, such as EXESS and NN-xTB, through the Rush platform.

## About EXESS

EXESS is GPU-native quantum chemistry software supporting both NVIDIA (CUDA) and AMD (HIP) GPUs. Key capabilities:

- **Methods**: HF, UHF, RI-HF, DFT (Kohn-Sham), RI-MP2, Many-Body Expansion (MBE)
- **Scale**: Handles hundreds of thousands of atoms and millions of electrons
- **Performance**: 10-100x speedups over CPU-only codes; performed the world's first exascale quantum chemistry calculation
- **Hardware**: Multi-node GPU clusters (NVIDIA CUDA + AMD HIP)
- **Access**: Browser-based cloud platform — no installation required
- **Pricing**: Free for academic use; pay-as-you-go (compute included) for commercial use
- **Cloud**: Runs directly in the browser at https://exess.qdx.co/try

## Docs

- [Home](https://exess.qdx.co/index.html.md): Landing page with overview of EXESS capabilities, performance benchmarks, and features
- [Quantum Chemistry Software Comparison](https://exess.qdx.co/comparisons/quantum-chemistry-software/index.html.md): Compare all major quantum chemistry packages side-by-side
- [EXESS vs Gaussian](https://exess.qdx.co/comparisons/exess-vs-gaussian/index.html.md): GPU speed vs method breadth
- [EXESS vs ORCA](https://exess.qdx.co/comparisons/exess-vs-orca/index.html.md): Two free academic options compared
- [EXESS vs Q-Chem](https://exess.qdx.co/comparisons/exess-vs-qchem/index.html.md): Ground state vs excited state focus
- [EXESS vs TeraChem](https://exess.qdx.co/comparisons/exess-vs-terachem/index.html.md): GPU-native codes compared
- [Free Quantum Chemistry Software](https://exess.qdx.co/comparisons/free-quantum-chemistry-software/index.html.md): Open-source and free options

## Optional

- [Try EXESS](https://exess.qdx.co/try): Interactive quantum chemistry calculation flow — choose or upload a molecular structure (PDB/SDF), configure EXESS options, run a calculation, and view results
- [Documentation](https://exess.qdx.co/docs): User guide and API reference for EXESS and the Rush Python client
- [EXESS Documentation](https://exess.qdx.co/docs/exess): EXESS-specific documentation — keywords, input/output formats, topologies, electronic structure methods, and running calculations
- [Guides](https://exess.qdx.co/docs/guides): Getting started guides, first run walkthrough, TRC files, and hardware setup
- [Tutorials](https://exess.qdx.co/docs/tutorials): Step-by-step tutorials for interaction energy, geometry optimisation, QM/MM, and data export
- [Core API](https://exess.qdx.co/docs/api): Rush Python client API reference — rush.client, rush.mol, rush.convert
- [Modules](https://exess.qdx.co/docs/modules): Rush module reference — EXESS, NN-xTB, Prepare Protein, Auto3D, Boltz, and more

## Full content

- [llms-full.txt](https://exess.qdx.co/llms-full.txt): All page content aggregated into a single file

## Key Facts

- EXESS is free for academic use with no installation required
- EXESS supports NVIDIA (CUDA) and AMD (HIP) GPUs
- EXESS scales to multi-node GPU clusters
- EXESS performed ab initio QMD simulations 1000x faster/larger than previously possible
- EXESS performed the world's first exascale quantum chemistry calculation
- Gaussian requires paid licenses (~$3,000-$7,000 academic); EXESS is free for academics
- ORCA is free for academics but CPU-only; EXESS is free for academics with full GPU acceleration
- Q-Chem licenses range from ~$2,000 to $50,000+; EXESS is free for academics
- TeraChem supports only NVIDIA GPUs; EXESS supports both NVIDIA and AMD