We have API, and bulk search facility for searching details with GST number.
Bulk search by name is not available and I am afraid that it will never be available.
Reason being that GSTN (body managing GST technology) has not released any API or facility to search with name.
At this site we have collected data from different sources and it is not complete. As of now we have details of around 37 lakh tax payers. But in reality there are around 95 lakh registered tax payers.
So, it will not be a good idea to charge for incomplete service.
However you can opt for bulk search or API search using GST numbers.