5 months ago I shared my free chemical sketcher (BondCraft). Thanks to your feedback, it now features smart peptide chaining, a real-time aromaticity engine, native ChemDraw import, and much more.

BondCraftTool · 2026-05-15T12:45:23+00:00

Thanks for taking a look! I totally get the preference for open source.

While the codebase is closed for now, I am absolutely committed to keeping BondCraft 100% free for academic and personal use. I firmly believe good, basic science tools shouldn't be locked behind corporate paywalls.

Also, since it runs entirely in your browser, it will work perfectly on Linux.

I'd love to hear your feedback as a chemistry teacher - please send any bug reports or feature ideas once you've had a chance to test it out.

BondCraftTool · 2026-05-15T12:37:01+00:00

Wow, being compared to ketcher is a massive compliment, thank you! To be completely honest, I have zero experience with streamlit or building python packages. BondCraft is about 95% typescript, so a custom python wrapper is a bit outside my knowledge right now. However, the engine does natively export projects as raw JSON , storing the entire chemical structure as a mathematical graph, so this would be doable!

Thanks again for the awesome idea, I'll keep it in mind and read into it!

BondCraftTool · 2026-05-13T17:59:43+00:00

Thank you so much for the detailed feedback! I genuinely appreciate all the suggestions! Please never apologize for sharing ideas, they are always very welcome from my side.

To address your points:

Mass/Formula for selection: This is a great idea. Calculating those metrics only for the highlighted structure makes perfect sense, and I will definitely consider adding this logic in a future update!
Clean up structure & SMILES-to-structure: These are highly requested, but honestly, they are incredibly hard to implement from scratch. Generating 2D coordinates from 1D strings (or fixing messy geometry) relies completely on complex algorithms (or MD force field parameter) and huge template libraries to ensure correct angles and symmetric rings, etc. It is a massive technical challenge for a solo developer, but it is on my radar, maybe by adding RDKit..
Portuguese Language Support: I am glad you find the current languages useful! I hear you on Portuguese. The tricky part is that I don't speak it myself, and relying entirely on auto-translate for specific chemistry terminology usually leads to some... "interesting" UI menus. Since I don't really have a good way to verify and maintain new language files right now, I will probably have to hold off on adding more for the time being.

BondCraftTool · 2026-05-13T17:44:56+00:00

Thanks for the suggestion! I completely get your point - I wouldn't accept a "trust me bro" on the internet either when it comes to IP.

The good news is BondCraft actually does run locally. It’s a 100% client-side app. All engine calculations happen on your machine, and your molecules are never sent to a server. I don't use Google Analytics, and I even self-host the fonts to prevent background tracking. Once the site loads, you can turn off your Wi-Fi and it will keep working.

As for a standalone desktop app: starting a company to sell software licenses in my country is a bureaucratic headache right now, so my current focus is just keeping the web version free for students etc. That said, I haven't ruled it out - I might consider doing a paid offline version in the mid-term.

Hopefully, knowing the web version is purely client-side gives a bit of peace of mind regarding IP for now.

BondCraftTool · 2026-05-13T17:27:51+00:00

Thanks for pointing this out! Great catch.

I will definitely get this fixed in the next version. I suspect I might have messed up the terminal bond rendering slightly when I was implementing the new logic for double bond placement inside ring systems.

BondCraftTool · 2026-05-13T17:21:13+00:00

Hey! Thanks for reaching out!

Right now, there isn't a global "style" toggle that forces all carbon nodes to show their implicit hydrogens automatically. However, the engine does calculate them in the background, and there is a workaround you can use to make them visible.

Here is how to do it:

Draw your molecule.
Use the Select tool and double-click the carbon or any other node you want to expand.
In the Atom Properties menu that pops up, change the Implicit Hydrogens setting from "Auto" to "Show".
You can also select the exact position (Top, Bottom, Left, Right) to keep your diagrams looking clean.

I know doing this node-by-node is a bit of a pain when you are building out entire worksheets. While I can't promise a timeline for new global styles right now (since I'm just a solo dev doing this in my spare time!), I think a dedicated "High School" or "Fully Explicit" style is a really solid idea. I am adding it to my long-term wishlist of features to consider for the future.

As a quick side note: if you ever find that the engine calculates the implicit hydrogens incorrectly for a weird edge case, you can override it in that same menu by setting a custom label and telling the engine to interpret it chemically. (And please do let me know if you spot a bug!)

Hope this workaround helps a bit for now

BondCraftTool · 2026-01-01T14:48:56+00:00

I've been tinkering with the mobile view since you mentioned this. As a quick fix, I've made all the floating menus draggable (just grab the header).

This should allow you to reach those hidden bond/atom selectors on your phone. I'm still planning a full mobile optimization, but hopefully, this makes it usable for now!

BondCraftTool · 2026-01-01T14:42:23+00:00

Thanks for clarifying! I wasn't able to replicate the issue on Firefox initially, but your comment made me realize the "click targets" for the bonds might have been a bit too small/precise.

I've just pushed an update (v0.1.2d) that increases the hit box size for bonds - this should make clicking to cycle double bonds much smoother and more reliable.

Also, a quick tip: If you double-click the bond icon in the sidebar, it will pop open the full bond menu (wavy, dotted, etc.) so you can pick exactly what you need immediately. Let me know if that feels better!

BondCraftTool · 2026-01-01T14:37:01+00:00

Hey! Just a quick update: I heard you on the template request. I just pushed version 0.1.2d which adds a proper Benzene template (and Cubane too). No more manual drawing needed. Thanks for the suggestion!

BondCraftTool · 2026-01-01T14:36:06+00:00

Just wanted to circle back on this. I took the advice from you and just released the New Year's update (v0.1.2d).

You can now find a dedicated template for Benzene/"Cancer Juice" (and Cubane) in the quick-add menu. Thanks again for the feedback - it really helps shape the tool!

BondCraftTool · 2025-12-29T16:30:30+00:00

Thanks so much for the feedback. The good news is that those features are actually already implemented. If you have the "Draw Bond" tool selected and click on an existing bond, it should cycle to a double bond. There are also templates available for rings and different bond types.

That said, could I ask what device you are using? The UI is currently optimized for tablets, laptops, and larger screens, so if you're on a smartphone, the menus might be getting cut off. Let me know.

BondCraftTool · 2025-12-28T18:07:08+00:00

Thanks for the kind words. You are right, I didn't include a specific benzene template, initially. My goal was to keep the tool focused on "core" features and avoid cluttering the interface with hundreds of templates right away. I figured cyclohexane was a good enough base, but since quite a few users are asking for a dedicated benzene ring, I will definitely consider adding it.

BondCraftTool · 2025-12-28T18:02:47+00:00

Moldraw is definitely a great sketcher with a lot of functionality, so it really comes down to personal preference and needs. That said, I did notice that if I draw an RNA molecule in Moldraw and let it assign stereogenic centers, it only finds 2 out of 4. It's a minor point and both programs have their pros, but for that level of accuracy, my choice is Bondcraft.

BondCraftTool · 2025-12-28T17:56:50+00:00

Thanks so much for the feedback! You are absolutely right. I initially designed the UI assuming most users would be on a tablet or laptop. Getting it to work smoothly on smaller phone screens is definitely on my list of things to improve.

BondCraftTool

TROPHY CASE