I prepared a web frontend for the Malayalam spellchecker based on the Malayalam morphology analyser.
It is available at https://morph.smc.org.in/spellcheck.html.
The spellchecker is available as an API too. If you want to use it, please refer a minimal code snippet available at codepen.
The quality of spellcheck and suggestions provided depend on the completeness of mlmorph project. Since mlmorph is ongoing and highly complex project, this will take time.