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Schrödinger Sketcher
An open-source editor for drawing molecules, reactions, and biomolecular sequences in desktop and web applications.
Open source. 33 of 65 checklist features confirmed.
Official demo
Main canvas
Native window frame changes; canvas and toolbars remain white.
Default drawings
Caffeine
Paclitaxel
No 3D view
Cholesterol in 3D
- SMILES paste generated a 2D layout automatically.
- Default heteroatom colors and stereo annotations were enabled.
- Paclitaxel required Fit to Screen to show the whole drawing.
- Default PNG export was white, 400 × 400 pixels, approximately 72 dpi.
- The app uses one canvas; Clear Sketcher started each fresh fixture.
Facts
- GitHub stars
- 43 stars on 6 Nov 2026
- First commit
- 22 Sept 2009
- Repository activity
- 2,340 commits, 64 contributors, last push 5 Nov 2026
- Latest version
- v2026-4
- Version we tested
- Release 2026-4 (build 131)
- Runs on
- Browser
- License
- Permissive BSD 3-Clause license.
- Price
- Free
- Relies on
- RDKit, InChI. Original Qt editor with RDKit; InChI import/export runs through RDKit.
- Draws with
- Qt QGraphicsScene and QPainter; QSvgGenerator for SVG and QImage for PNG
- Chemistry from
- RDKit
- Interface
- Qt Widgets, compiled to WebAssembly for the browser
- Main language
- C++
- Other languages
- TypeScript: Browser React wrapper and API; JavaScript: Qt WebAssembly browser loader and glue; C: InChI identifier library
- Renderer
- Original: Sketcher Qt graphics-item renderer
- Third-party licenses
- Includes LGPL-3.0-only (Qt), MPL-2.0 (Eigen), and OFL-1.1 (bundled Arimo fonts).
- Download
- 19 MB
- Installed
- 48 MB
- CDXML import is supported; CDXML export is unsupported.
- Native image export is limited to PNG and SVG.
- General custom-fragment saving is not implemented.
In use
Screenshots from our test of this version.
Single, double and triple bonds
Bond menu lists single, double and triple bond orders.
Wedge, hash and wavy bonds
Wavy, solid wedge and hashed wedge bonds on the canvas.
Dative, hydrogen and quadruple bonds
Bond type menu lists coordinate and zero-order bonds.
Ring tools
Cyclohexane and benzene rings alongside the ring toolbar.
Template library
A monomer on the canvas beside the amino acid library.
Charges, isotopes and atom labels
Atom menu offers element and charge controls.
Radicals and lone pairs
Atom menu includes Add Unpaired Electron.
Lasso select and transforms
Modify menu offers horizontal and vertical flips.
Reaction arrows
A forward arrow on the drawing canvas.
Color control
2D settings show heteroatom coloring and a color mode.
Structure checking
View menu shows Valence Errors enabled.
R/S and E/Z labels
R and S labels appear on a stereochemical structure.
Peptides and nucleic acids
A monomer on the canvas beside amino acid and nucleic tabs.
MOL and SDF
Format menu lists MDL SD V3000.
SMILES
Format menu lists SMILES and Extended SMILES.
InChI
Format menu lists InChI and InChIKey.
High-resolution PNG
Caffeine structure on a white background.
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 and double; changed double to triple. Opens the screenshot.Single, double and triple bondsDrew single and double; changed double to triple.github.com
- Yes, tested by running it: Drew solid/hash wedges; set unknown stereo to zigzag. Opens the screenshot.Wedge, hash and wavy bondsDrew solid/hash wedges; set unknown stereo to zigzag.github.com
- Yes, according to the manual: Dative and zero-order bonds. Opens the cited page.Dative, hydrogen and quadruple bondsDative and zero-order bonds.github.com
- Not establishedChoose double-bond side
- Yes, tested by running it: Placed cyclohexane and benzene with dedicated tools. Opens the screenshot.Ring toolsPlaced cyclohexane and benzene with dedicated tools.github.com
- Not establishedChair and Haworth rings
- Yes, according to the manual. Opens the cited page.Chain toolgithub.com
- Yes, tested by running it: Placed an alanine monomer from the amino-acid library. Opens the screenshot.Template libraryPlaced an alanine monomer from the amino-acid library.github.com
- No: General custom-fragment saving is explicitly unimplemented. Opens the cited page.Save your own templatesGeneral custom-fragment saving is explicitly unimplemented.github.com
- Not establishedGroup abbreviations
- Yes, according to the manual. Opens the cited page.Charges, isotopes and atom labelsgithub.com
- Yes, according to the manual: Unpaired-electron controls; lone pairs unverified. Opens the cited page.Radicals and lone pairsUnpaired-electron controls; lone pairs unverified.github.com
- Yes, according to the manual. Opens the cited page.Keyboard drawinggithub.com
- Partly: Lasso, rotate and flip; structure resizing unverified. Opens the cited page.Lasso select and transformsLasso, rotate and flip; structure resizing unverified.github.com
- Not establishedTilt drawings in perspective
Reactions and mechanisms
- Partly: Placed forward arrow; other arrow styles unverified. Opens the screenshot.Reaction arrowsPlaced forward arrow; other arrow styles unverified.github.com
- No: No curved electron-arrow tool found in inspected toolbar or menus. Opens the cited page.Curved mechanism arrowsNo curved electron-arrow tool found in inspected toolbar or menus.
- Yes, according to the manual: RDKit reactions and reaction SMILES/RXN exchange. Opens the cited page.Machine-readable reactionsRDKit reactions and reaction SMILES/RXN exchange.github.com
- Yes, according to the manual: Manual mapping by dragging between matching reactant and product atoms. Opens the cited page.Atom mappingManual mapping by dragging between matching reactant and product atoms.github.com
- Not establishedOrbitals and symbols
Figures and layout
- Not establishedRich text captions
- Partly: Chemical subgroup brackets; general shapes and curves unverified. Opens the cited page.Shapes, brackets and curvesChemical subgroup brackets; general shapes and curves unverified.github.com
- Not establishedAlign and distribute
- Not establishedGroup and ungroup
- Yes, according to the manual. Opens the cited page.2D structure cleanupgithub.com
- Not establishedJournal drawing styles
- Not establishedReusable custom styles
- Partly: Element palettes; individual object coloring unverified. Opens the cited page.Color controlElement palettes; individual object coloring unverified.github.com
- Yes, according to the manual: Per-atom and per-bond colored halos through rendering APIs. Opens the cited page.Color highlightingPer-atom and per-bond colored halos through rendering APIs.github.com
- Not establishedPage layout and multipage
- Not establishedImported pictures
- Not establishedTLC plates and tables
Chemistry intelligence
- Yes, according to the manual. Opens the cited page.Structure checkinggithub.com
- Yes, tested by running it: R/S labels appeared automatically on imported paclitaxel and cholesterol. Opens the screenshot.R/S and E/Z labelsR/S labels appeared automatically on imported paclitaxel and cholesterol.github.com
- No: No formula/mass command found in action menus or property dialog. Opens the cited page.Formula and massNo formula/mass command found in action menus or property dialog.
- Not establishedProperty estimates
- No: Importing caffeine as text returned Unable to determine format. Opens the cited page.Name to structureImporting caffeine as text returned Unable to determine format.
- No: No naming command in conversion menus; chemical formats only. Opens the cited page.Structure to nameNo naming command in conversion menus; chemical formats only.
- Not establishedNMR prediction
- Yes, according to the manual: R-groups, element lists and query constraints. Opens the cited page.R-groups and query structuresR-groups, element lists and query constraints.github.com
- Yes, according to the manual: SRU polymers, copolymers and repeat patterns. Opens the cited page.Polymers and repeat unitsSRU polymers, copolymers and repeat patterns.github.com
- Yes, tested by running it: Placed alanine monomer; amino-acid and nucleic-acid libraries visible. Opens the screenshot.Peptides and nucleic acidsPlaced alanine monomer; amino-acid and nucleic-acid libraries visible.github.com
- Not establishedImage to structure
- Not establishedOnline structure lookup
- No: No 3D viewer found; imported 3D SDF displayed on 2D canvas. Opens the cited page.3D model viewNo 3D viewer found; imported 3D SDF displayed on 2D canvas.
- Not establishedCrystal structures
Files and exchange
- Partly: Imported methanol CDXML; no CDXML option in export formats. Opens the cited page.CDXML import and exportImported methanol CDXML; no CDXML option in export formats.github.com
- Not establishedCDX import and export
- Yes, tested by running it: Imported V2000 MOL and 3D SDF; exported V3000 MOL. Opens the screenshot.MOL and SDFImported V2000 MOL and 3D SDF; exported V3000 MOL.github.com
- Yes, tested by running it: Pasted fixture SMILES; exported imported methanol as CO. Opens the screenshot.SMILESPasted fixture SMILES; exported imported methanol as CO.github.com
- Yes, according to the manual: InChI import and export; InChIKey export. Opens the cited page.InChIInChI import and export; InChIKey export.github.com
- Yes, according to the manual: RXN import and V3000 export. Opens the cited page.RXN filesRXN import and V3000 export.github.com
- Yes, tested by running it: Saved svg-test.svg using SVG image format. Opens the cited page.SVG exportSaved svg-test.svg using SVG image format.github.com
- No: Only PNG/SVG formats; Command-P opened no print dialog. Opens the cited page.PDF exportOnly PNG/SVG formats; Command-P opened no print dialog.github.com
- Partly: Default 400×400 PNG, approximately 72 dpi; higher resolution unverified. Opens the screenshot.High-resolution PNGDefault 400×400 PNG, approximately 72 dpi; higher resolution unverified.github.com
- Not establishedPaste to and from ChemDraw
- Not establishedEditable in Word or PowerPoint
- Not establishedWindows Office OLE
APIs and automation
- Yes, according to the manual: Documented SIP wrapper sets and retrieves molecular structures. Opens the cited page.Python APIDocumented SIP wrapper sets and retrieves molecular structures.learn.schrodinger.com
- Yes, according to the manual: Typed React/WASM API for structure and image exchange. Opens the cited page.JavaScript or TypeScript APITyped React/WASM API for structure and image exchange.github.com
- Yes, according to the manual: Bundled headless SMILES-to-HELM converter. Opens the cited page.Command-line toolBundled headless SMILES-to-HELM converter.github.com
- Not establishedAI agent control
- Not establishedBuilt-in AI assistant
Embedding and extension
- Not establishedPlugins
- Yes, according to the manual: React iframe wrapper requires self-hosted WASM assets; native Qt SketcherWidget available. Opens the cited page.Embed in your own appReact iframe wrapper requires self-hosted WASM assets; native Qt SketcherWidget available.github.com