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A Slack employee working in a meeting room in Slack’s Melbourne office. Photo credit: Slack
A term for lazing around is now also the name of the world’s fastest-growing workplace messaging app.
Slack is barely five years old, but already boasts of 9 million weekly active users and over 50,000 paid teams, including 43 percent of the Fortune 500 companies. The company is valued at US$5 billion.
Slack’s engineering team takes up over a third of the 1,000-strong headcount. Co-founder and CTO Cal Henderson tells Tech in Asia how the company hires and retains talent in Silicon Valley, one of the most engineer-hungry places in the world.
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Cal Henderson, co-founder and CTO of Slack. Photo credit: Slack
Hiring process for engineers
Slack is overhauling its hiring process for engineers, but it generally looks like this:
- Resume screening
- A phone call with a hiring manager or technical recruiter
- A take-home technical exercise that will be graded
- A series of onsite interviews
- An offer within the day or the next day
The length of the whole process varies, depending on the candidate’s availability and the time they take to complete the take-home exercise. In the shortest case, the gap between applying and getting an offer could last a week.
Assessing candidates
Take-home tests
Slack’s founding team has been against whiteboard coding exercises from the beginning.
“There’s been a lot of research showing that they are super exclusionary,” says Henderson, “It gets rid of a whole bunch of people who would be great at the job but bad at doing algorithms on a whiteboard, which is completely unrelated to how anybody actually works.”
At the same time, however, a candidate’s technical ability also has to be assessed. Slack’s solution to this is their take-home technical exercise, which candidates can do at their own time and pace.
To increase diversity in the engineering team, Henderson recognizes the need to create an environment where people of all working styles are given a fair assessment.
“I’m quite proud of the diversity of our engineering team today, but there’s still a long way to go,” he says. “In order to remove bias from the hiring process, we’re now looking at offering different options to people for their technical assessment. Whether they want to do a take-home exercise, come onsite and do whiteboard programming, or come onsite to do a pair programming exercise, we’re figuring out what the best assessment is for someone’s level of technical skill.”
Doing interviews
For Slack’s engineering team, however, technical competence is not enough – they’re also looking for candidates who have a lot of user empathy.
“At the end of the day, we’re not building software for software’s sake,” says Henderson. “We’re building tools to help people accomplish a task. We have to be thinking about our users through that process, like understanding people’s frustrations or things they will find difficult.”
On how to gauge user empathy during an interview, Henderson says the basic way would simply be to ask them about it. “If they are curious and driven to learn more about the users, their enthusiasm will show,” says Henderson. “Then there will be people who will be like, ‘Oh, I don’t really care.’ People say the darnest things during interviews and filter themselves out like that!”
The team also doesn’t tolerate “excellent jerks” — people who are really good at their jobs but are very difficult to work with.
“This tends to be quite easy to spot in the hiring process,” he shares, “These are people who have switched jobs a ton, and hate every company they’ve worked at. That’s a big red flag. We’re looking for people who will work at Slack for several years and will build a team around themselves.”
“The best engineers are not just excellent at their craft, but they’re also excellent at lifting up the craft of everyone around them,” says Henderson. “The desire to get better at your craft, and make your team better is infectious. The idea that A players hire other A players and B players hire C players is definitely true.”
He stresses the importance of a company’s first few hires and the people chosen for senior management positions. These are the ones who will be critical in building and maintaining the culture of the organization.
As such, Henderson himself interviewed the first 200 people in the engineering team, going through over a thousand interviews in Slack’s first few years, to build a strong team and culture early on.
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Slack at the Grace Hopper Celebration of Women in Computing Conference. Photo credit: Slack
Firing fast
Another key to building a strong team is being quick to fire people who aren’t working out.
“It’s very rare that you let someone go and be like, ‘Well I wished we could have been a bit slower about that.’ It’s nearly always, ‘Gosh I wish I’d done that months ago!’ You get that relief and weight lifted when somebody who wasn’t working out in the team leaves the company,” he says.
Henderson believes that firing quickly is a lot more important in a small startup.
“If you’re 10 people and there’s one bad person on the team, that’s a real dragging force on the whole company,” he explains.
Hiring challenges
The biggest challenge Slack faces in hiring engineers is the huge competition for engineering talent in Silicon Valley.
“It’s very rare that we’re the only person offering somebody a job,” he says. “If they’re a great candidate, they can work absolutely anywhere. Some companies pay a ridiculous amount of money, others have the prestige. We’ve had candidates who go, ‘I’d really like to join Slack, but my parents have heard of Google, so I’m going to join Google instead.'”
But it wasn’t always this way.
“Right at the beginning, we had people who were very risk accepting,” he says. “They understand that they could work for another company, but see the potential in Slack. Then we got into an awkward phase where we’re no longer a super young startup, but not super well-known either — that was pretty difficult. Now we’re in a phase where nearly everyone who’s coming to interview at Slack has at least heard of us before. But that also means we’re competing with companies who have been around forever and are made of money.”
On the bright side, those who join Slack are now people who see the value of the product, believe in the product mission, and are aligned with that mission from the get-go.
Henderson believes that what differentiates Slack from more established companies is that Slack is still small enough for engineers to make a big impact.
On top of that, Slack also has a clear mission because of its simplicity as a single product that’s focused on a particular use case, which happens to be one that people can relate well with.
“It’s not at all speculative, and all of the work is focused on driving this product forward. That’s the advantage we have,” he says. “But that’s a disadvantage at the same time. If Google X is trying to recruit people to work on say, space computers, that’s the kind of appeal that’s hard for us to compete with. You’ll be working on software for businesses, which is pretty exciting at Slack, but not putting balloons that surf the internet in space or whatever they’re doing this week. You just can’t compete with that.”
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The breakout space at Slack’s San Francisco office. The team uses the space for trainings and show and tell sessions. Photo credit: Slack
Retaining engineers
As Slack grows from a startup to a larger organization, Henderson admits that it’s a challenge to keep employees who signed up for a 20-person company but now find themselves working in a 1,000-person one.
“The way we now work is very different,” he says. “It’s a very different kind of person we’re hiring now compared to who we were hiring four years ago.”
To retain their employees, Slack invests in mapping out a good career growth path for every engineer, whether it’s going into management or growing into a role as a senior contributor.
“Everyone wants to switch to management. It’s such a terrible job – being an engineer is way more fun,” Henderson adds with a laugh.
“In fact, we’ve seen quite a few people switch to the management track, hated it, and have switched back to being an individual contributor,” he says. “It’s making sure that being an individual contributor is a path that we not only allow, but also promote at Slack. Junior engineers should see that becoming a manager is not the only way to continue your career here, and we could point to a few key individual contributors and say, ‘That’s a viable path for you, too.'”
Slack also has a buddy program for new hires: each new hire is paired up with a “team buddy” (a senior member of the team), as well as an “onboarding buddy” (someone else from another team in engineering). The team buddy will get them up to speed within the team, and the onboarding buddy will help them on their engineering journey at Slack.
“I think part of becoming more senior is the ability to mentor younger engineers, or a younger manager,” shares Henderson. “That’s a very valuable part of growth for both the mentor and the mentee.”
A lot of the senior members within the team have outside mentorship, and in turn, mentor people from other companies. “As you get more senior, it’s good to have an outside perspective from other companies to get a sense on where you’re going,” he says.
Advice for potential candidates
“Apply to us!” invites Henderson. “The best way to get noticed is to have a real enthusiasm for improving the product and helping make users’ lives better.”
“Be enthusiastic, be empathetic. But please, please do not show up, break into the Slack office, and leave a shrine on someone’s desk. Know the difference between being enthusiastic and going too far,” he quips.
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