The devil works hard, but your new boss works harder if you spot these warning signs.

While many people meticulously vet prospective gigs ahead of time, some warning signs can be observed in the interview itself. As a service to applicants, job-holders have shared “red flags” to look out for while being grilled by their potential employers, as seen in a viral Reddit thread.

“What’s a red flag everyone should be aware of when attending a job interview?” the original poster inquired in the post.

One possible indicator of a hell gig, per the thread, is if the prior holder of said position left in a hurry.

“I once turned down a job offer because they mentioned that the previous person in the position had quit after a few months, and most of the people I interviewed seemed stressed out,” said one Redditor.

Another Redditor cautioned against taking jobs where you have to invest in the company “in order to work there,” writing: “I interviewed for a window installation company and did well on the test. They wanted me in sales and said I needed to pay for a laptop. They would cover it and take it out of my checks if I didn’t have the cash to pay upfront.”

One user advised applicants to avoid firms that describe themselves as “one big happy family” as this likely means that they “expect you to be super available all the time and put the job above everything else, even your actual life.”

By a similar token, interviewers shouldn’t pry too much into an aspiring employee’s personal life.

“Had a guy one time ask me how old my children were,” said one commenter. “I think he was trying to suss out if I would be able to work all kinds of crazy hours.”

They also warned applicants to look out for gigs where everyone has been there three years or fewer as this means there’s a lot of turnover — the only exception being if it’s a new company.

Another Redditor advised applicants to avoid jobs where “employees are either new hires or have been there for 15+ years with no in-between.”

“There is no room for improvement — it’s better to leave for advancement,” they warned.

A boss who rails against “clock watchers” is another giant piece of career caution tape as this indicates they might expect “more work for no extra pay,” one Redditor declared.

They claimed that this type of employer will get mad when you leave at 5 even when it’s your contract-mandated quitting time.

Another glaring red flag? A preponderance of reviews lambasting the company on sites like Glassdoor, per the thread.

“I brought up a company’s awful Glassdoor reviews and they got so mad they ended the interview,” claimed one Redditor. “Well, guess I dodged that bullet.”

“I brought up one really bad customer review to the owner, and he told me that [the] business owner was a jerk and just had it out for him,” wrote another. “I didn’t dodge that bullet, got hired, and went through a really hellish 4 months before leaving. The ‘jerk’ was right. My boss was the problem.”

Meanwhile, employment experts also advise applicants to be suspicious of firms that have no online presence whatsoever either (barring firms in stealth startup mode).

“Any company that isn’t publishing content — or doesn’t have a Web site or an online presence — is not competing successfully in today’s economy,” branding expert Dan Schawbel, author of “Promote Yourself: The New Rules for Career Success,” told the Post in 2016. “And you don’t want to work there, because they’re going to go out of business. It will inhibit your success.”