There are no federal regulations that govern how an employer should be posting jobs on their own career site, other than site accessibility requirements. There are also no federal regulations that require employers to announce open jobs via job postings to the employer's career site. What you might be referring to is the Mandatory Job Listing requirement under the VEVRAA regulation, which applies to businesses who have a contract with the federal government of $150,000 or more, and which requires them to list their jobs with the state-run Employment Service Delivery System (ESDS) or state job bank as a condition of their federal contract. However, this requirement does not stipulate any listing obligation with respect to privately-run or other career sites, including employer career sites. The requirement, which can be found in the Equal Opportunity Clause of the VEVRAA regulation states that: “Listing of employment openings with the appropriate employment service delivery system pursuant to this clause shall be made at least concurrently with the use of any other recruitment source or effort and shall involve the normal obligations which attach to the placing of a bona fide job order, including the acceptance of referrals of veterans and nonveterans.” By "concurrently," this means that a contractor must list or post their jobs with the Employment Service Delivery System (ESDS) as soon as they start recruiting for it, and keep the posting active until it is filled. The regulations do not specify a minimum or maximum number of days that jobs must be posted on the ESDS, but you do need to keep it active for as long as you are recruiting for it, so ESDS representatives working to place veterans can continue to refer qualified protected veterans to your open jobs.