Click the MolDraw icon
From any tab: a paper on a publisher site, a PDF in the browser, lecture slides, Wikipedia, a supplier catalogue. The page dims and the cursor turns into a crosshair. The page is frozen so nothing scrolls under you.
Coming soon · Chrome Web Store
Snip any molecule. Edit it in MolDraw.
The MolDraw addon for Chrome and Edge turns any structure image on a web page or PDF into an editable molecule. Click the icon, drag a box around the structure like a snipping tool, and MolDraw opens with the result ready to edit.
Google Chrome
Microsoft Edge
Web pages · PDFs · Slides
journal.example.org/articles/aspirin-synthesis
Try it: drag a box over the structure in the mock page.
How it works
Three steps, nothing to draw by hand. The addon behaves like the Windows Snip tool, but the result is chemistry you can edit.
Drag a box around the structure
Only the region you select is captured, at your screen's full resolution, exactly as you see it on screen — including anything inside modals or image lightboxes.
Open it in MolDraw
Mathpix chemistry OCR reads the crop and returns SMILES. MolDraw opens in a new tab with the structure fully editable: change substituents, add reagents, export to SVG, PNG, MOL or copy to Word.
What you get
Built for people who read papers all day and redraw far too many structures.
Snip, not screenshot
Click-and-drag selection with a live size read-out. Works on HiDPI displays and with browser zoom without offset. Esc cancels at any time.
Mathpix chemistry OCR
Uses Mathpix's structure recognition to turn drawn molecules into SMILES, including multi-structure figures and reaction schemes.
Straight into MolDraw
The result opens in the editor you already use, with the SMILES available to copy. Reactions open in MolDraw's reaction mode.
Nothing stored by MolDraw
The crop goes from your browser to Mathpix and back. MolDraw only receives the resulting SMILES in the URL. Your keys live in your browser profile.
Chrome and Edge
Manifest V3 extension. Identical behaviour in Google Chrome and Microsoft Edge on Windows, macOS and Linux.
Alt + Shift + M
Start a capture without reaching for the toolbar. The keys can be changed in your browser's extension shortcuts.
Details
What the addon needs and what it does with it.
| Availability | Coming soon on the Chrome Web Store and Edge Add-ons. Currently in private testing. |
|---|---|
| Price | The addon is free. Structure recognition uses your own Mathpix OCR API account (pay-as-you-go, billed by Mathpix). |
| Setup | Paste your Mathpix app_id and app_key directly in the extension popup. That's the whole setup. |
| Input | Any region of a web page or in-browser PDF, selected by dragging. Captured at device pixel resolution. |
| Output | SMILES (single molecules, multiple structures, reactions with >>), opened at moldraw.com/?smiles=… |
| Permissions | activeTab, scripting and storage only. Runs when you click; no background tracking. |
| Browsers | Google Chrome 102+, Microsoft Edge 102+ (Manifest V3). |
Roadmap
Where the addon is today.
In-page snipping
Crosshair overlay, page freeze, HiDPI-accurate crop, Mathpix conversion, open in MolDraw. Chrome and Edge.
Chrome Web Store listing
Store review and public release so installation is one click, with automatic updates.
Right-click on images
Convert an image directly from the context menu, plus batch capture of figures with several structures.
Frequently asked
Does it work on PDFs?
Yes. For PDFs opened in the browser the addon captures the visible page and lets you drag the snip box over the structure.
Does it work in Microsoft Edge?
Yes. Edge is built on the same extension platform as Chrome, so the addon is identical there.
Why do I need a Mathpix account?
Mathpix provides the chemistry recognition (image → SMILES). Using your own key keeps the addon free and means MolDraw never sees your screenshots.
What if the structure is recognised incorrectly?
The structure opens in MolDraw where you can fix it in seconds. A tighter crop with only one structure and no caption gives the best results.
Will there be Word and PowerPoint addons?
Yes, they are in development. See the addons page.
Want early access, or a feature the addon should have? Tell us — we implement relevant requests fast.
Request a feature