Free lunches. Yoga. Gym Memberships. Pet-friendly offices. In the tech world, every startup's perks one-ups the next. Don't get me wrong, perks are great; they are great for recruiting and they are great for retention. But over the last few years, we are seeing a noticeable shift in our conversations with candidates and employees; today's workers are savvier and much more interested in the work and the culture than the perks. In fact, employee engagement is a much higher indicator of a happy employee -- something I've witnessed first hand as a recruiting lead at Zynga, Okta and now Twilio.

The stats back it up. According to the Gallup Organization, highly engaged organizations have double the rate of success of lower engaged organizations. Double. When an engaged workforce impacts your bottom line as much as we know it does, engaged employees are your competitive edge. The question is, of course, how do you create those?

Excluding all company perks, here are a few ways to encourage employee engagement:

1. Encourage employees to be social.

A recent study reports that having a close friend at work boosts employee engagement by 50%. To encourage those relationships, host events in the office, encourage teams to get together outside of work, create common spaces for working, eating, chatting and empower employees to organize around the things they are passionate about. It matters!

At Twilio, employees have created "employee resource groups" that promote, celebrate and encourage people who identify with different cultures. It's become another great way for employees to socialize with those outside their department and helps people find a sense of community and support within the larger organization.

2. Write down your values.

First of all, have a set of values. Then, write them down, share them on your website, paint them on a wall and talk about them often. Employees who say their organizational values are "known and understood" are 51 times more likely to feel engaged in their work.

One of my favorite Twilio values is "draw the owl." It's derived from a popular Internet meme but what it really means is that nobody is going to tell you how to do your work. Your job is much more than your job description and you are the one responsible for figuring out an approach to reach your goals. We believe that if we're truly innovating, there is never going to be an instruction book for how to get our work done. Draw the Owl started off as one of Twilio's values and has transformed into a mantra of sorts reminding everyone to figure out a way to have an impact.

3. Keep teams small.

Disruption occurs when you work on small teams where everyone is accountable, works hard, thinks smart and moves fast. Being a part of a small team with a common goal fosters a culture of ownership where employees feel personally responsible for the success of that team and achievement of that goal. Most importantly, keeping teams smalls protects that hungry startup culture even as the company grows.

4. Promote.

Recognize exceptional work, promote high performers and have a strategy that focuses on the personal growth of each individual employee. In my opinion, this strategy should hold as much weight as any other company strategy. Employees are 78% more likely to remain at a company if their career path is clear.

To make this happen, managers must be trained and then empowered to build their teams and invest in the growth of their reports. If I ask an employee what role they are working towards and when they expect to achieve a promotion and they can't provide an answer, I know we could be doing better.

5. Give everyone a voice.

Instead of waiting for employees to voice their concerns, be proactive about creating channels for them to give feedback. Companies can do this through continuous feedback and manager 1:1s, employee surveys, anonymous Q&As but most importantly, they must consider the different personalities and communication styles of your employees. The responsibility is twofold - companies must ask for feedback in a variety of ways and employees are then responsible for having an opinion.

6. Be flexible.

It's proven that workers with less strict work environments achieve more, are sick less often and are happier in their work. The first step in making flexibility a part of your culture is to remove the expectation that everyone requires the same hours, environment or set up to be productive.

Encourage managers to identify what works best for their reports. Some workers may prefer to start their days early and leave in time to pick up kids from school. Others may prefer to skip the rush hour commute and shifting their workday from mid-morning to mid-evening. Measure success by goals achieved rather than hours spent in the office.

The bottom line? Invest in creating a team of happy employees. There is simply no greater driver of business success.