InChI and InChIKey from a structure, in the browserDraw or paste a structure and read its InChI, its InChIKey and each of its layers separately, or paste an identifier and see what it draws. The IUPAC engine itself runs in the page, compiled to WebAssembly, so nothing is uploaded.An InChI is a prologue followed by layers — the formula, the connections, the hydrogens, then charge, stereochemistry and isotopes — each introduced by a slash and a letter. The layers are what make it comparable rather than merely unique.Convert a structure to its InChI and InChIKey and back, convert a whole CSV, XLSX or SDF file, learn how the identifier is derived, and practise writing its layers. The InChI engine is WebAssembly running in your browser, so the tool needs JavaScript — and nothing you open ever leaves your machine.

Convert — a structure in, an InChI out

Batch — a whole CSV, XLSX or SDF file

Tutorial — how an InChI is derived

Exercises — write the layers yourself

Cheatsheet — every layer in a table

Tests — the IUPAC regression corpora

Download — take the engine away

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