Perhaps no Boston start-up embodies the shifting sands of business and the youthful, risk-taking Gen Y spirit quite like HubSpot. Perhaps that’s because co-founder Brian Halligan himself found success as a 25-year-old, and is now paying forward that risk-taking faith in young talent: 85 percent of HubSpot’s 800 employees worldwide are under the age of 34. HubSpot, and Halligan, clearly know what millennials want and how businesses can change to be more in synch with them. Indeed, the marketing software company’s recent IPO puts them in an ideal spot to share Gen Y’s idealism.

To find out more about HubSpot’s proven expertise attracting and retaining millennial talent, we sat down with Kristen Kenny, director of people operations:

Bentley: Why is HubSpot one of the best places for millennials to work?

HubSpot: Our open atmosphere, our transparency, and the social aspects of our culture are all things that make HubSpot a place where millennials really thrive. We try to ensure that millennials have the opportunity to give back, and pick internal champions for fundraising drives within the company for organizations like charity:water. We also have community days as part of our onboarding process, where our new hires get together as a team and give back.

Do you feel there’s a preparedness gap between millennial workers and the requirements of the workplace?

In this day and culture, especially at HubSpot, we cater to the millennial target because we need to, because it’s the new generation of workers. Our culture is mostly millennial and my observation is that preparedness isn’t so much lacking but that expectations differ between what new grads have been taught in school and what the actual realities of the workplace are. Or sometimes it’s just a difference in generational expectations between younger millennials and those of us who have been in the workforce longer.

Do you ever find it difficult to manage millennial employees?

At any age, there’s difficulty in managing employees, and it all depends on the age difference between the manger and the employee. We work hard to train our managers, and we’ve revamped our management training with programs to help with that. But millennials will always tell you when they think they’re not being managed well. Every quarter, we ask for Net Promoter Scores (NPS) from our employees — scores both for the company and for their managers — and the confidential responses are very detailed with great feedback. “Do you think HubSpot is a great place to work? Would you recommend it to a friend?” At the end of each survey, we post a summary on our internal wiki and skew the raw data to keep it confidential. We post what Brian Halligan calls “hot chilies,” and the more chilies something has, the more important it is to address, which makes it a better place to work for everyone, not just millennials.

Do you have any formal or informal mentorship programs in place?

From the start, every new hire in our onboarding process is given access and introductions to our executives and other colleagues. A lot of our executives have informal one-on-one lunches with employees, which any employee can request to set up. It’s a good program that many people take advantage of, and which can lead to more formal mentorships, but we also have such an open-door atmosphere that people can just walk up to anyone at any level and start a conversation that can turn into deeper relationships — an atmosphere that CMO Mike Volpe calls “not just an open-door policy, but a no-door policy.” It’s pretty amazing that at 800 people we can still maintain that open atmosphere, even in HR. The only two offices with doors are legal and payroll.

Do you actively encourage or provide opportunities for your millennial employees/colleagues to network outside the company?

Absolutely. We’re part of the Massachusetts Technology Leadership Council (Mass TLC) and encourage our employees to attend or speak at those networking events. In addition, if employees see that Brian or another colleague is going to any networking event or speaking locally on a panel or at a forum, they’ll make an effort to attend. We always promote where our HubSpot people are going and what they’re involved in so that it gives others the opportunity to take advantage. Recently, I was on a panel at Mass TLC about our unlimited vacation time policy, which got me out networking with other human resources people, and we encourage all of our employees to do the same. (Read more about unlimited-vacation time policy in this recent BusinessWeek article.)

Do you actively encourage or provide opportunities for your millennial employees to further their education or acquire new soft and hard skills through classes, conferences, or other opportunities?

Every HubSpot employee can get $5,000 per year for tuition reimbursement, and they can take classes within any certified education program. We also have a training development team of five people that works on management training, service team training, personality training, and building other internal training programs that employees request. Employees also attend various conferences, like usability training or training on various software and systems. These help make them better at doing their job and make HubSpot a better place to work.

Do you have a mission-driven culture? Eighty-eight percent of millennials said in the Bentley PreparedU study that it was a priority to work for companies that are socially responsible and ethical, making the world a better place.

Our overall mission is about making the world less interruptive and more relevant, which is a mission that millennials naturally understand: They grew up being able to tune out marketing that is irrelevant. As a result, many of the folks who join our team right out of school are really passionate about that mission. Beyond that, we have many opportunities to give back in a meaningful way, from our annual charity auction to a huge fundraising push with charity: water at our INBOUND conference the last few years. We try to strike a balance between company-wide initiatives and team and employee-led initiatives, and we’re fortunate that we have a good combination of both and some great partner organizations to give back to.

In your experience, how important is work-life balance to your millennial employees? And how do you handle that as a company?

At HubSpot, we encourage people to build their work around their life — there’s a real focus on autonomy and giving people the personal responsibility. We give you unlimited time off for a reason: We want you to work hard, because that’s what we expect from all of our employees, but we also want you to know when it’s time to take a break. On November 1, we just launched a sabbatical program where very employee, at their five-year employment anniversary, will receive one month of paid time off, with their job secured when they return, as well as a monetary bonus to enjoy during that time off on top of their normal salary.

What kinds of things does your company do to help millennials succeed in business?

All of the things we do as a company are designed to help people be more successful, to get people to the next level, and then even take that learning and experience to their next opportunity. If you go back to HubSpot’s Culture Code, we hire really smart people who have H.E.A.R.T, an acronym that stands for Humble, Effective, Adaptable, Remarkable and Transparent. It’s something that co-founders Dharmesh Shah and Brian Halligan are passionate about, and hiring those types of people makes it easier for them to be part of HubSpot’s culture. (Halligan is famous for recruiting young, promising talent and giving them big responsibility, which he expands upon in this Business Insider article.)

What are the top three things that other companies could learn from your experiences about hiring, employing and/or retaining millennials?

It’s the culture, it’s the benefits, it’s hiring for that right fit. Hire for the culture, and make sure your code is authentic to your culture, a living, breathing document that you regularly revisit and make sure is still true, and talk about how to make sure it is. Retaining talent is all about providing the opportunities to reap the great benefits, like our social atmosphere, stocked fridge, beer fridge, nap room, our Halloween and holiday parties — including significant others, even if you’re a large company, allowing employees to share your culture with those people who matter to them.

What else should we know about why your company is a progressive workplace and one of the best places and cultures for millennials to thrive?

We’re always looking at what’s going on in the world. How do we keep up with what’s going on in our employees’ lives? How do we make it easier for them to be here? We’ve done a really good job of that in our space, and regularly win awards for being one of the top 10 coolest office spaces (among the ranks of Google, Zappos and other companies known for their culture). We make it an exciting place to come and to work hard.

Melissa Massello is a freelance writer, former start-up executive, and serial entrepreneur who is passionate about supporting women’s leadership and gender equality, both in business and at home.