The best way to host your internal job board on your intranet is to use iFrame to embed your board on your site. Your iFrame link is located under Job boards & posts > Edit Board Settings > Dev Center > Embed Code.
Note: Internal job post iFrames are only available to organizations using the new customizable job board customization.
Customers with legacy job boards can add their job posts to their internal site using Greenhouse Harvest API. Your developers can use the Harvest endpoint GET: List job posts to programmatically construct links to your internal job board.
Check out the following article for more information: Can I host my internal job board outside of Greenhouse?