Chemistry, minus the fume hood

Every great story starts with a bond.

Ejja Chem is a free structure editor that lives in your browser. Sketch molecules and reactions, then export them wherever you like. No install, no account, no lab coat required (but we won't judge).

Let's get reacting, it's free Show me the goods
  • 100% in your browser, zero side reactions
  • SMILES · MOL · SDF · KET · PNG · SVG
aspirin.mol
OH O O O
CC(=O)Oc1ccccc1C(=O)O
C9H8O4 180.16
0 sto install (we checked)
8file formats
100+templates & fragments
Localyour data stays put, like a noble gas
Features

Everything you need, no catalyst required

Homework sketch at 2am or the figure for your thesis, we've got you. Here's what's in the flask.

Fast drawing

Bonds, rings, chains and atoms, with keyboard shortcuts for when you're in the zone. Benzene in one click, because nobody enjoys drawing six sides.

Reactions & mechanisms

Arrows, plus signs, conditions, the whole plot. Follow atoms from reactants to products and find out who ended up with whom.

One-click tidy-up

Wonky bonds? Clean Up straightens angles and lengths faster than you can say "VSEPR".

Chemistry checks

Formula, molecular weight, stereocenters, charges. It'll tell you when a carbon has five bonds. Carbon hates that.

Export anywhere

SMILES and MOL for databases, SVG and PNG for slides and papers. Copy to clipboard in one click, no titration needed.

Private by nature

Your drawings never leave your machine. Only names you search for go to PubChem. Your molecules stay inert to prying eyes.

Workflows

Whatever brought you here

Survive organic chemistry (and maybe even enjoy it)

  • Sketch mechanisms and catch valence mistakes before your TA does
  • Formula and molecular weight update live, no calculator
  • Paste clean images straight into lab reports
Try it with an example →

From idea to identifier before your coffee cools

  • Paste SMILES or MOL files and edit them visually
  • Canonical SMILES, InChI and SDF, ready for registration
  • R-groups, stereochemistry and query features, for the serious stuff
Open the editor → 
// export from Ejja Chem (coffee not included)
SMILES  CN1C=NC2=C1C(=O)N(C(=O)N2C)C
Formula C8H10N4O2
MW      194.19 g/mol
InChI   1S/C8H10N4O2/c1-10-4-9-6-5…

Figures even Reviewer 2 can't complain about

  • Consistent bond lengths and angles with Clean Up
  • Crisp SVG that scales from poster to billboard
  • Transparent PNGs for slides, docs and websites
Make a figure →
Coffee break

Chemistry jokes, periodically

For when your chromatography column is taking its sweet time.

More of a gamer?Over 100 molecules, a classic mode and a survival mode. It won't go on your report card, promise.
Import & export

Fluent in every format chemistry speaks

Move structures between Ejja Chem, lab notebooks, databases and documents. Retyping SMILES by hand should be illegal.

Open editor
SMILESLine notation
MOLMDL V2000 / V3000
SDFStructure-data file
RXNReactions
KETNative JSON
InChIIUPAC identifier
SVGVector image
PNGRaster image
FAQ

You asked, we reacted

Is Ejja Chem free?

Yep. Free as in free radical. No account, no sign-up.

Are my structures uploaded anywhere?

Nope. The chemistry engine runs right inside your browser tab and your drawings stay with you. One exception: when you search a molecule by name, that name is sent to PubChem and Wikidata to find the structure.

Which browsers are supported?

Any recent Chrome, Edge, Firefox or Safari. Tablets work too, but a mouse makes precise drawing way easier.

What powers the editor?

Ejja Chem is built on Ketcher, the open-source structure editor by EPAM, plus the Indigo toolkit, both Apache 2.0. Standing on the shoulders of giants (and their carbon atoms).

Do you know any chemistry jokes?

We'd tell you one, but all the good ones argon. (The survivors are in the coffee break section above.)

Ready to make some bonds?

Open the editor and start sketching. It's faster than balancing a redox equation, we promise.

Launch Ejja ChemSupport the project