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KetchDraw
Browser-based molecular drawing editor combining Ketcher structure editing with RDKit property calculations.
Open source. 41 of 65 checklist features confirmed.
Main canvas
No dark mode
Default drawings
Caffeine
Paclitaxel
Cholesterol in 3D
- The hosted page identifies itself as BoltzDraw; About identifies Ketcher 2.24.0.
- Imported SMILES produced centered drawings with colored heteroatom labels.
- Paclitaxel's central labels and bonds overlap in the automatic layout.
- The wrapper property panel continued to show zero molecules after imports.
- The SMILES-derived 3D view looked flat; the supplied SDF showed depth.
Facts
- GitHub stars
- 0 stars on 6 Nov 2026
- First commit
- 24 Dec 2025
- Repository activity
- 18 commits, 2 contributors, last push 28 Mar 2026
- Version we tested
- 2.24.0
- Runs on
- Browser
- License
- MIT stated in README without a separate license file; bundled Ketcher uses Apache-2.0.
- Price
- Free
- Relies on
- Ketcher, RDKit, Indigo. Embedded Ketcher supplies drawing; RDKit calculates properties and Indigo handles chemistry.
- Draws with
- SVG in the Ketcher editor and RDKit.js previews; Indigo renders SVG/PNG exports
- Chemistry from
- RDKit.js and Indigo through Ketcher standalone WebAssembly
- Interface
- HTML/CSS/JavaScript wrapper around a React-based Ketcher iframe
- Main language
- TypeScript
- Other languages
- JavaScript: Wrapper and molecule analysis interface; C++: Indigo exports and RDKit previews
- Renderer
- Borrowed: Ketcher; Indigo exports; RDKit previews
- Third-party licenses
- Ketcher/Indigo Apache-2.0; RDKit BSD-3-Clause; Chart.js/React MIT. Indigo rendering bundles Cairo (LGPL-2.1 OR MPL-1.1) and Noto Sans fonts (OFL-1.1).
- README calls it KetchDraw; the hosted interface calls it BoltzDraw.
- RDKit and Chart.js load from public CDNs; pKa calculations use a remote API.
- Property cards use exact mass for MW and hardcode unspecified stereocenters to zero.
In use
Screenshots from our test of this version.
Single, double and triple bonds
Single, double, and triple bonds on the drawing canvas.
Wedge, hash and wavy bonds
Solid wedge, hashed wedge, and wavy bonds on the canvas.
Ring tools
A benzene ring alongside bond examples on the canvas.
Template library
Structure library lists sugars, bicycles, amino acids, and other templates.
Save your own templates
Save Structure dialog with a disabled Save to Templates button.
Charges, isotopes and atom labels
Caffeine drawing with nitrogen and oxygen labels and element controls.
Lasso select and transforms
Selection palette with rectangle, lasso, and fragment icons.
Reaction arrows
Reaction arrow palette with forward and equilibrium arrow styles.
Curved mechanism arrows
Curved half-headed arrow on the drawing canvas.
Shapes, brackets and curves
Shape palette with ellipse, rectangle, and line icons.
Formula and mass
Calculated formula, molecular weight, and exact mass.
3D model view
Miew viewer displaying a molecular model with coordinate axes.
CDXML import and export
Open Structure dialog containing CDXML text.
MOL and SDF
Save Structure dialog with MDL Molfile V2000 selected.
Features
- Tested by running it
- Seen in the app
- The manual says yes
- Partly, with the reason shown
- Not supported
- Not established, which is not the same as no
Select a mark for its proof. A filled mark opens our screenshot, or the manual if the check left nothing to picture. A ring opens the manual.
Drawing structures
- Yes, tested by running it: Drew single, double and triple bonds. Opens the screenshot.Single, double and triple bondsDrew single, double and triple bonds.github.com
- Yes, tested by running it: Drew wedge, hash and wavy bonds. Opens the screenshot.Wedge, hash and wavy bondsDrew wedge, hash and wavy bonds.github.com
- Yes, according to the manual: Dative and hydrogen bonds. Opens the cited page.Dative, hydrogen and quadruple bondsDative and hydrogen bonds.github.com
- Not establishedChoose double-bond side
- Yes, tested by running it: Placed benzene; multiple ring sizes available. Opens the screenshot.Ring toolsPlaced benzene; multiple ring sizes available.github.com
- Yes, according to the manual: Built-in chair and boat templates. Opens the cited page.Chair and Haworth ringsBuilt-in chair and boat templates.github.com
- Yes, according to the manual. Opens the cited page.Chain toolgithub.com
- Yes, according to the manual. Opens the cited page.Template librarygithub.com
- Yes, according to the manual. Opens the cited page.Save your own templatesgithub.com
- Yes, according to the manual. Opens the cited page.Group abbreviationsgithub.com
- Yes, according to the manual. Opens the cited page.Charges, isotopes and atom labelsgithub.com
- Yes, according to the manual: Monoradical and singlet/triplet diradical atom settings. Opens the cited page.Radicals and lone pairsMonoradical and singlet/triplet diradical atom settings.github.com
- Yes, according to the manual. Opens the cited page.Keyboard drawinggithub.com
- Partly: Lasso, rotate, flip; resizing covers images, shapes and arrows. Opens the cited page.Lasso select and transformsLasso, rotate, flip; resizing covers images, shapes and arrows.github.com
- Not establishedTilt drawings in perspective
Reactions and mechanisms
- Yes, tested by running it: Placed forward and equilibrium arrows on separate canvases. Opens the screenshot.Reaction arrowsPlaced forward and equilibrium arrows on separate canvases.github.com
- Yes, tested by running it: Placed curved half-headed arrow. Opens the screenshot.Curved mechanism arrowsPlaced curved half-headed arrow.github.com
- Yes, according to the manual: RXN reaction serialization. Opens the cited page.Machine-readable reactionsRXN reaction serialization.github.com
- Yes, according to the manual. Opens the cited page.Atom mappinggithub.com
- Not establishedOrbitals and symbols
Figures and layout
- Yes, according to the manual: Font size, bold, italic, subscript and superscript. Opens the cited page.Rich text captionsFont size, bold, italic, subscript and superscript.github.com
- Yes, according to the manual: Ellipse, rectangle and line tools; S-groups provide brackets. Opens the cited page.Shapes, brackets and curvesEllipse, rectangle and line tools; S-groups provide brackets.github.com
- Not establishedAlign and distribute
- Partly: Chemical groups move together; mixed text/shape grouping unverified. Opens the cited page.Group and ungroupChemical groups move together; mixed text/shape grouping unverified.github.com
- Yes, according to the manual. Opens the cited page.2D structure cleanupgithub.com
- Not establishedJournal drawing styles
- Yes, according to the manual: Font and bond settings persist in browser storage. Opens the cited page.Reusable custom stylesFont and bond settings persist in browser storage.github.com
- Not establishedColor control
- Partly: API highlights display colored halos; exports omit them. Opens the cited page.Color highlightingAPI highlights display colored halos; exports omit them.github.com
- Not establishedPage layout and multipage
- Yes, according to the manual: PNG and SVG images. Opens the cited page.Imported picturesPNG and SVG images.github.com
- Not establishedTLC plates and tables
Chemistry intelligence
- Yes, according to the manual: Invalid atom valences are underlined in red. Opens the cited page.Structure checkingInvalid atom valences are underlined in red.github.com
- Yes, according to the manual: Calculate CIP assigns R/S and E/Z. Opens the cited page.R/S and E/Z labelsCalculate CIP assigns R/S and E/Z.github.com
- Yes, tested by running it: Caffeine: C8H10N4O2, molecular weight 194.191. Opens the screenshot.Formula and massCaffeine: C8H10N4O2, molecular weight 194.191.github.com
- No: Wrapper property panel stayed empty after importing molecules. Opens the cited page.Property estimatesWrapper property panel stayed empty after importing molecules.github.com
- No: Entering caffeine in structure import produced conversion error. Opens the cited page.Name to structureEntering caffeine in structure import produced conversion error.
- No: No naming command found in inspected controls. Opens the cited page.Structure to nameNo naming command found in inspected controls.
- Not establishedNMR prediction
- Yes, according to the manual. Opens the cited page.R-groups and query structuresgithub.com
- Yes, according to the manual: SRU repeat units with head-to-tail or head-to-head connectivity. Opens the cited page.Polymers and repeat unitsSRU repeat units with head-to-tail or head-to-head connectivity.github.com
- Not establishedPeptides and nucleic acids
- No: Recognition explicitly rejects requests in standalone mode. Opens the cited page.Image to structureRecognition explicitly rejects requests in standalone mode.github.com
- Not establishedOnline structure lookup
- Yes, tested by running it: Imported 3D SDF rotates in Miew viewer. Opens the screenshot.3D model viewImported 3D SDF rotates in Miew viewer.github.com
- Not establishedCrystal structures
Files and exchange
- Yes, tested by running it: Exported and reopened caffeine CDXML. Opens the screenshot.CDXML import and exportExported and reopened caffeine CDXML.github.com
- Yes, according to the manual: Binary CDX import; binary and Base64 CDX export. Opens the cited page.CDX import and exportBinary CDX import; binary and Base64 CDX export.github.com
- Yes, tested by running it: Imported MOL and SDF; exported MOL. Opens the screenshot.MOL and SDFImported MOL and SDF; exported MOL.github.com
- Yes, tested by running it: Imported and exported SMILES. Opens the cited page.SMILESImported and exported SMILES.github.com
- Yes, according to the manual. Opens the cited page.InChIgithub.com
- Yes, according to the manual. Opens the cited page.RXN filesgithub.com
- Yes, tested by running it: SVG downloads saved successfully. Opens the cited page.SVG exportSVG downloads saved successfully.github.com
- No: No PDF option in save format list. Opens the cited page.PDF exportNo PDF option in save format list.
- Partly: PNG exported at 553 by 392 pixels; no resolution control. Opens the cited page.High-resolution PNGPNG exported at 553 by 392 pixels; no resolution control.github.com
- Not establishedPaste to and from ChemDraw
- Partly: Imports embedded ChemDraw objects from PowerPoint; editable Office insertion unverified. Opens the cited page.Editable in Word or PowerPointImports embedded ChemDraw objects from PowerPoint; editable Office insertion unverified.github.com
- No: Office support only imports ChemDraw objects from PowerPoint. Opens the cited page.Windows Office OLEOffice support only imports ChemDraw objects from PowerPoint.github.com
APIs and automation
- Not establishedPython API
- Yes, according to the manual: Underlying Ketcher JavaScript API is accessible through the iframe. Opens the cited page.JavaScript or TypeScript APIUnderlying Ketcher JavaScript API is accessible through the iframe.github.com
- Not establishedCommand-line tool
- Not establishedAI agent control
- Not establishedBuilt-in AI assistant
Embedding and extension
- Not establishedPlugins
- Partly: Bundled Ketcher only (Apache-2.0); full wrapper embedding undocumented. Opens the cited page.Embed in your own appBundled Ketcher only (Apache-2.0); full wrapper embedding undocumented.github.com