We are not providing ontology publicly online anywhere, but we have a list of domains and sub-domains available, and you can download the list from here.
The ontology is generated using these domains and subdomains based on resume job profiles and skills.
This will help you integrate your site with RChilli Resume Parsing API and help you in industry, sector, and skills categorizations.
You can download the list and further match it with your data, which would make the integration with the RChilli API easier for you. There are ontology-driven fields such as category, skill ontology, etc., and there are significant improvements in the Skills fields.