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OpenReactions
Browser editor for chemical structures, reaction mechanisms, animations, and composed scientific figures.
License unclear. 34 of 65 checklist features confirmed.
Main canvas
Default drawings
Caffeine
Paclitaxel
Cholesterol in 3D
- SMILES imports generated 2D layouts without a cleanup command.
- Caffeine, paclitaxel, and cholesterol MOL exports retained fixture stereochemistry in RDKit.
- The 3D viewer generated a ball-and-stick model with hydrogens shown.
- Image exports cropped to the drawing; PNG used a 2× canvas scale.
- No app version was shown in About; the served JavaScript filename supplies the build ID.
Facts
- Version we tested
- Hosted, 5 Nov 2026
- Runs on
- Browser
- License
- No product license stated.
- Price
- Not published
- Relies on
- OpenChemLib. OpenChemLib dependency confirmed by bundled license notice; editor provenance remains unestablished.
- Draws with
- HTML Canvas 2D for drawings; SVG for figures and vector export; jsPDF/svg2pdf for PDF.
- Chemistry from
- OpenChemLib
- Interface
- React
- Main language
- JavaScript
- Other languages
- None
- Renderer
- Original: Custom Canvas/SVG renderer
- Third-party licenses
- Includes BSD-3-Clause (OpenChemLib) and MIT (React).
- Browser-local drawings stay in that browser; cross-device saving requires sign-in.
- No product license, pricing, or release version found in official documentation.
- Interactive behavior was not tested; findings rely on documentation and served code.
In use
Screenshots from our test of this version.
Single, double and triple bonds
Bond tools and a structure with single and double bonds
Wedge, hash and wavy bonds
Stereo bond tools and a structure with wedge and hashed bonds
Ring tools
Ring tools and aromatic rings on the canvas
Charges, isotopes and atom labels
Element and charge controls beside a labeled structure
Reaction arrows
Forward and equilibrium arrow tools in the reaction toolbar
Curved mechanism arrows
Curved arrow tools in the reaction toolbar
3D model view
3D molecular model with hydrogen and rotation controls
High-resolution PNG
PNG output showing the caffeine structure
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 triple; clicked single to make double. Opens the screenshot.Single, double and triple bondsDrew single and triple; clicked single to make double.openreactions.com
- Yes, tested by running it: Placed solid, hashed, and wavy bonds. Opens the screenshot.Wedge, hash and wavy bondsPlaced solid, hashed, and wavy bonds.openreactions.com
- Not establishedDative, hydrogen and quadruple bonds
- Not establishedChoose double-bond side
- Yes, tested by running it: Placed benzene; several ring sizes appear in toolbar. Opens the screenshot.Ring toolsPlaced benzene; several ring sizes appear in toolbar.openreactions.com
- Yes, according to the manual: Dedicated chair and Newman tools. Opens the cited page.Chair and Haworth ringsDedicated chair and Newman tools.openreactions.com
- Not establishedChain tool
- Yes, tested by running it: Placed a morpholine fragment from the library. Opens the cited page.Template libraryPlaced a morpholine fragment from the library.openreactions.com
- Yes, according to the manual: Structure fragments saved locally as SMILES. Opens the cited page.Save your own templatesStructure fragments saved locally as SMILES.openreactions.com
- Yes, according to the manual: Recognized groups can be expanded or contracted. Opens the cited page.Group abbreviationsRecognized groups can be expanded or contracted.openreactions.com
- Partly: Charges and labels editable; isotopes imported through SMILES/MOL. Opens the cited page.Charges, isotopes and atom labelsCharges and labels editable; isotopes imported through SMILES/MOL.openreactions.com
- Yes, according to the manual: Lone-pair tool also supports single-electron dots. Opens the cited page.Radicals and lone pairsLone-pair tool also supports single-electron dots.openreactions.com
- Yes, according to the manual: Hover over an atom and type its label. Opens the cited page.Keyboard drawingHover over an atom and type its label.openreactions.com
- Partly: Box selection, rotation, flipping; resizing only in Figure mode. Opens the cited page.Lasso select and transformsBox selection, rotation, flipping; resizing only in Figure mode.openreactions.com
- Not establishedTilt drawings in perspective
Reactions and mechanisms
- Yes, tested by running it: Placed forward and equilibrium arrows. Opens the screenshot.Reaction arrowsPlaced forward and equilibrium arrows.openreactions.com
- Partly: Placed a curved electron-pair arrow; editing unverified. Opens the screenshot.Curved mechanism arrowsPlaced a curved electron-pair arrow; editing unverified.openreactions.com
- Yes, according to the manual: RXN import and export preserve reactants and products. Opens the cited page.Machine-readable reactionsRXN import and export preserve reactants and products.openreactions.com
- Not establishedAtom mapping
- Yes, according to the manual: Figure symbol palette includes Greek letters, charges, and arrows. Opens the cited page.Orbitals and symbolsFigure symbol palette includes Greek letters, charges, and arrows.openreactions.com
Figures and layout
- Partly: Fonts and styling; sub/superscripts use limited Unicode symbols. Opens the cited page.Rich text captionsFonts and styling; sub/superscripts use limited Unicode symbols.openreactions.com
- Yes, according to the manual: Editable shapes and freehand brush paths. Opens the cited page.Shapes, brackets and curvesEditable shapes and freehand brush paths.openreactions.com
- Yes, according to the manual: Selected objects align left, top, or center. Opens the cited page.Align and distributeSelected objects align left, top, or center.openreactions.com
- Yes, according to the manual. Opens the cited page.Group and ungroupopenreactions.com
- Yes, according to the manual: Tidy structure regenerates coordinates with OpenChemLib. Opens the cited page.2D structure cleanupTidy structure regenerates coordinates with OpenChemLib.openreactions.com
- Not establishedJournal drawing styles
- Not establishedReusable custom styles
- Yes, according to the manual. Opens the cited page.Color controlopenreactions.com
- Yes, according to the manual: Figure highlighter draws exportable translucent colored strokes across structure regions. Opens the cited page.Color highlightingFigure highlighter draws exportable translucent colored strokes across structure regions.openreactions.com
- Partly: Page-size presets; figure documents contain one page. Opens the cited page.Page layout and multipagePage-size presets; figure documents contain one page.openreactions.com
- Yes, according to the manual: PNG, JPEG, and WebP image insertion. Opens the cited page.Imported picturesPNG, JPEG, and WebP image insertion.openreactions.com
- Not establishedTLC plates and tables
Chemistry intelligence
- Yes, according to the manual: Basic structure check flags valence and stereochemistry issues. Opens the cited page.Structure checkingBasic structure check flags valence and stereochemistry issues.openreactions.com
- Not establishedR/S and E/Z labels
- Yes, tested by running it: Caffeine: C8H10N4O2 and 194.19 g/mol. Opens the cited page.Formula and massCaffeine: C8H10N4O2 and 194.19 g/mol.openreactions.com
- Not establishedProperty estimates
- No: Caffeine entered as SMILES produced a parse error. Opens the cited page.Name to structureCaffeine entered as SMILES produced a parse error.
- No: Info and menus showed no naming command. Opens the cited page.Structure to nameInfo and menus showed no naming command.
- Not establishedNMR prediction
- Partly: R atom tool appears; query behavior unverified. Opens the cited page.R-groups and query structuresR atom tool appears; query behavior unverified.
- No: Repeat-unit brackets are graphical; chemical polymer export unsupported. Opens the cited page.Polymers and repeat unitsRepeat-unit brackets are graphical; chemical polymer export unsupported.openreactions.com
- Not establishedPeptides and nucleic acids
- Not establishedImage to structure
- Not establishedOnline structure lookup
- Yes, tested by running it: Generated cholesterol model and rotated it. Opens the screenshot.3D model viewGenerated cholesterol model and rotated it.openreactions.com
- Not establishedCrystal structures
Files and exchange
- No: CDXML probe rejected; no CDXML export shown. Opens the cited page.CDXML import and exportCDXML probe rejected; no CDXML export shown.
- Not establishedCDX import and export
- Yes, tested by running it: Imported MOL and SDF; exported both formats. Opens the cited page.MOL and SDFImported MOL and SDF; exported both formats.openreactions.com
- Yes, tested by running it: Imported SMILES and copied generated SMILES. Opens the cited page.SMILESImported SMILES and copied generated SMILES.openreactions.com
- Not establishedInChI
- Yes, according to the manual: Single reaction arrow required; agent structures rejected on import. Opens the cited page.RXN filesSingle reaction arrow required; agent structures rejected on import.openreactions.com
- Yes, tested by running it: Exported SVG drawings. Opens the cited page.SVG exportExported SVG drawings.openreactions.com
- Yes, tested by running it: Exported PDF; no raster images found inside. Opens the cited page.PDF exportExported PDF; no raster images found inside.openreactions.com
- Partly: PNG exported at 760×812; no 300 dpi setting found. Opens the screenshot.High-resolution PNGPNG exported at 760×812; no 300 dpi setting found.openreactions.com
- Not establishedPaste to and from ChemDraw
- Not establishedEditable in Word or PowerPoint
- Not establishedWindows Office OLE
APIs and automation
- Not establishedPython API
- Not establishedJavaScript or TypeScript API
- Not establishedCommand-line tool
- Not establishedAI agent control
- Not establishedBuilt-in AI assistant
Embedding and extension
- Not establishedPlugins
- Not established: Hosted editor found; no supported embedding route confirmed.Embed in your own appHosted editor found; no supported embedding route confirmed.openreactions.com