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Chemvas is an open-source chemical drawing app where chemists and AI agents work on the same editable canvas. Start in the desktop app, let an agent continue through a purpose-built CLI, then open the editable result right back on the canvas.
Draw it yourself. Hand it to AI. Keep editing.
- Draw it yourself. Sketch structures, insert SMILES, label reaction arrows, and align molecules on the desktop canvas, with autosave and crash recovery. SMILES insertion needs the optional RDKit backend.
- Hand the same drawing to an AI agent. The CLI can compose documents, inspect stable atom IDs, apply bounded graph patches, check layouts, and render figures without opening the desktop app. Graph Patch binds each proposal to the exact source hash and validates the complete result before writing a new file.
- Keep editing the result. Composed and patched drawings remain native,
reopenable
.chemvasdocuments. Export SVG, PDF, PNG, or TIFF at explicit physical sizes while keeping the editable drawing alongside the figure.
Your saved drawings stay usable
Future Chemvas updates will continue to open currently supported, valid v7
.chemvas documents. Newer file formats must preserve that reading support;
older applications are not guaranteed to open newly saved formats.
See the document compatibility policy.
Install
Requires Python 3.12+. Install the optional RDKit backend for SMILES insertion,
Molecule Info (formula and identifiers), 3D XYZ export, abbreviation MOL export,
Suggest by structure, and pack-step:
pip install "chemvas[rdkit]"
chemvas
pip install chemvas skips RDKit. Drawing, .chemvas save/open, figure export
(SVG/PDF/PNG/TIFF, including editable SVG), and plain MOL import/export remain
available. Local Windows builds:
packaging notes.
Your first reaction scheme
- Choose Ring, type
OCc1ccccc1in its SMILES field, click Insert, then click the canvas. Hover the oxygen, press Enter, label itOH. - Insert
O=Cc1ccccc1to the right. Choose Arrow, drag between the two structures, then double-click the arrow to label it. - Edit ▸ Select All, then Edit ▸ Align ▸ Middle.
- Save as
.chemvas. File ▸ Export Figure… → Plain SVG, Fit 2-column (174 mm).
The step-by-step guide has the label text and the downloadable files. The drawing is an exercise, not an experimental result.
Scripts
With the downloaded first-scheme.chemvas:
chemvas inspect-document first-scheme.chemvas
chemvas check-layout first-scheme.chemvas
chemvas render-document first-scheme.chemvas --output first-scheme.pdf --width-mm 174
Rendering writes a new file and never touches the source. Composition, Graph Patch, scheme layout and their limits: document CLI guide · scheme layout · publication recipe.
Documentation
- Drawing tools and shortcuts · Chemistry I/O · Image objects · Limits and roadmap
- Calculation handoff (RDKit): elementary steps with separately embedded components, one
machine.jsonper step. - Documents are editable
.chemvasJSON files (version 7). More examples - Contributing · Architecture · Changelog · Releasing · MIT License
Something got in your way? Open an issue.
1 maintainer
Release files for chemvas 0.17.1
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| chemvas-0.17.1.tar.gz | 712.5 kB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| chemvas-0.17.1-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 1.6 MB
Release files / chemvas-0.17.1.tar.gz
| Download URL | chemvas-0.17.1.tar.gz |
|---|---|
| Size | 712.5 kB |
| Tags | Source |
|
SHA-256 checksum How to use checksums |
c539770ca3b1104c36bbee8e859981fa6fef7bd5e595d54c5c2c9a17ad4549d5
|
|
BLAKE2b-256 checksum How to use checksums |
2d012c07e11a0ed4dfef732c3a58da7a4d6f29710fb0d5f9999afa29d7b9c02a
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| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
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PyPI Publish Attestation
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Signed by GitHub Actions, verified by PyPI on Sep 21, 2026.
Transparency logRelease files / chemvas-0.17.1-py3-none-any.whl
| Download URL | chemvas-0.17.1-py3-none-any.whl |
|---|---|
| Size | 890.5 kB |
| Tags | Python 3 |
|
SHA-256 checksum How to use checksums |
720151c5efd8109d76448f0bb47371e1c429c5c4bf0c722c950684a31cab78e8
|
|
BLAKE2b-256 checksum How to use checksums |
3dc05806a5d0aafe0b6bea72fbf68c408e7b0c361d88f86f0eae2a27ec61e659
|
| Upload date | |
|
Uploaded using Trusted Publishing? What is trusted publishing? |
Yes |
| Uploaded via |
twine/7.0.0 CPython/3.13.14
|
Provenance
Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.
PyPI Publish Attestation
PyPI verified that this artifact, at this checksum, originated from the publisher listed below.
Signed by GitHub Actions, verified by PyPI on Sep 21, 2026.
Transparency log
