Draw Hexafluoroacetone from its SMILES, O=C(C(F)(F)F)C(F)(F)F. Any drawing of the right molecule is accepted, whichever way it is laid out.
Convert between chemical structures and SMILES in both directions, search a list of structures by substructure or SMARTS, and learn the notation step by step. Everything runs in your browser — no structure you open ever leaves your machine — so the tool needs JavaScript.