If a recruiter messages or emails you, make sure they’re doing so from a legitimate account. If they reached out via email, check their handle to see if it’s from a corporate website. If not, ask them to email you from their company email address. If they refuse or don’t respond, it’s likely a scam. For LinkedIn, perform a search on the company a recruiter works for when they reach out to you. Usually the first few results should clue you in.