Developer Alex Caithness let us know about his free online patch editor for the Volca FM and Yamaha DX7, Synthmata.
Synthmata is a patch editor that runs entirely within your Web browser (Chrome or Opera currently supported). It gives you full control over all of the parameters and makes it easy to share and save patches.
Here’s a video demo:
Caithness is also interested in collaborating with web developers and synth makers to extend the editor to support other synthesizers. He can be reached via oscillatorsink(at symbol)gmail.com
If you try Synthmata, share your thoughts on it in the comments!