Compare / Slack vs Zoom
AT A GLANCE
FUNDING HISTORY
Slack
Zoom
BUSINESS MODEL
Slack
Slack uses a freemium model. The free tier gives you access to your most recent 90 days of messages and 10 app integrations.
That's enough to get hooked. Then Slack charges per user per month — $8.75/month for Pro, $15/month for Business+, and custom pricing for Enterprise Grid.
The beauty of the model is that one person signs up, invites their team, the team gets addicted, and suddenly the company is paying for 500 seats. It's a virus that charges rent.
Zoom
Zoom uses a freemium model. Free accounts get unlimited one-on-one meetings and 40-minute group meetings.
Paid plans start at $13.33/month per user for Pro (meetings up to 30 hours), $18.33/month for Business, and custom pricing for Enterprise. Zoom also charges for add-ons — Zoom Phone (cloud phone system), Zoom Rooms (conference room hardware), and Zoom Contact Center.
The free tier is the hook. The 40-minute limit on group calls creates just enough friction to push power users to pay.
And once one person in a company pays, the whole team follows because nobody wants to be the one whose meetings keep getting cut off.
HOW THEY STARTED
Slack
Stewart Butterfield had already done this exact thing once before. In 2002, he was building a massively multiplayer online game called Game Neverending.
The game flopped but one of its features — a photo-sharing tool — became Flickr, which Yahoo bought for $35 million in 2005.
So in 2009, Butterfield did it again. He started a company called Tiny Speck to build another game called Glitch — a quirky, non-violent MMO where players collaborated instead of fighting.
The game was beautiful, weird, and a complete commercial failure. It shut down in November 2012 after never finding a big enough audience.
But the internal communication tool the Glitch team had built for themselves was something special. They had created a searchable, organized messaging system because email was driving them insane.
Every conversation was in channels. Everything was searchable.
Files were shared inline. It was everything email should have been but wasn't.
Butterfield looked at this internal tool and thought: this is the actual product. In August 2013, Slack launched in preview.
Within 24 hours, 8,000 companies had signed up. Within two weeks, it was 15,000.
The growth was so fast that Butterfield said it felt like "trying to drink from a fire hose."
Zoom
Eric Yuan grew up in Tai'an, a mining city in Shandong province, China. In 1997, he was 27 and inspired by the internet boom happening in America.
He applied for a US visa. He was rejected.
He applied again. Rejected again.
Eight times total over two years before he finally got approved in 1997. He moved to Silicon Valley with barely any English and joined WebEx as one of its first engineers.
Yuan spent 14 years at WebEx, eventually becoming VP of Engineering. Cisco acquired WebEx in 2007 for $3.2 billion.
Yuan watched Cisco slowly bloat the product with enterprise features while the core video quality deteriorated. He kept telling Cisco leadership they needed to rebuild the product from scratch.
They kept saying no.
In 2011, Yuan quit and took 40 WebEx engineers with him. He founded Zoom Video Communications with a simple thesis: video meetings should just work.
No downloads. No lag.
No "can you hear me?" No IT department required. He built the product that Cisco refused to build.
HOW THEY GREW
Slack
Slack grew almost entirely bottom-up. Nobody sold Slack to companies.
Employees adopted it on their own and then convinced their bosses to pay for it. One developer would start using the free version, invite their team, and within weeks the whole department was hooked.
IT departments would discover that half the company was already on Slack before anyone asked for approval.
The integrations strategy was genius. Slack made it dead simple for other software tools to plug into Slack.
Instead of checking Jira for bug reports, Salesforce for deals, and GitHub for code changes, everything pushed notifications into Slack. Slack became the operating system of work — the one app you kept open all day.
Word of mouth was the main growth driver. Slack didn't spend heavily on advertising early on.
They spent on making the product feel delightful. The loading messages were funny.
The emoji reactions were addictive. The search actually worked.
People genuinely liked using it, which is almost unheard of for enterprise software.
Zoom
Zoom grew on one thing: it worked. In a world where every video call started with five minutes of technical issues, Zoom calls just connected.
That reliability was the entire marketing strategy for the first five years.
The freemium model did the rest. Teachers, coaches, therapists, book clubs, and small teams all started on the free tier.
When they hit the 40-minute limit, enough of them converted to paid. And every free meeting was essentially a demo — everyone in the meeting saw how good Zoom was.
Yuan obsessed over simplicity. While competitors like WebEx and GoToMeeting required downloads, plugins, and IT involvement, Zoom worked in the browser with one click.
The learning curve was essentially zero. Your grandmother could figure it out.
That turned out to be extremely important when a pandemic suddenly required your grandmother to figure it out.
Then COVID happened. In March 2020, the world shut down.
Every meeting — work, school, family, doctor, church, happy hour — moved to video. Zoom was already the easiest option.
Daily participants exploded from 10 million to 300 million in four months. The stock went from $70 to $588.
THE HARD PART
Slack
Microsoft Teams was the existential threat. When Microsoft bundled Teams for free with Office 365 in 2017, Slack knew it was in trouble.
Microsoft had 300 million Office users who could start using Teams without paying anything extra. Slack even took out a full-page newspaper ad welcoming Microsoft to the chat market — a bravado move that masked genuine fear.
By 2020, Teams had overtaken Slack in daily active users purely on distribution.
The pandemic was a double-edged sword. Remote work exploded demand for Slack, but it also exploded demand for Teams, Zoom, and every other collaboration tool.
Slack's growth accelerated but so did everyone else's. The window where Slack was the obvious default was closing.
Revenue growth started slowing. After years of 50%+ annual growth, Slack's growth rate dropped to the low 30s by 2020.
Wall Street punished the stock, which dropped from its IPO price. The writing was on the wall — Slack couldn't outrun Microsoft alone.
In December 2020, Salesforce announced it was acquiring Slack for $27.7 billion. Butterfield stayed on as CEO until 2023, then left.
Zoom
The post-pandemic hangover has been severe. Zoom's stock peaked at $588 in October 2020 and crashed to under $70 by 2022 — an 88% drop.
The company went from the most exciting tech stock on the planet to a cautionary tale about pandemic valuations. Revenue growth slowed from 300%+ to single digits as people returned to offices and competitors caught up.
Security and "Zoombombing" were early crises. In early 2020, as millions of new users flooded in, trolls discovered they could join open Zoom meetings and share offensive content.
Schools, churches, and AA meetings were disrupted. It turned out Zoom's encryption wasn't truly end-to-end as advertised.
Yuan had to halt all feature development for 90 days and focus exclusively on security fixes. It was a near-death reputational crisis.
Competition from Microsoft Teams and Google Meet intensified. Both companies bundled video calling for free into products that hundreds of millions of people already used.
Microsoft Teams integrated directly into Office 365. Google Meet was built into Gmail.
Zoom had to compete against free products from two of the richest companies on Earth.
THE PRODUCTS
Slack
Slack is the core messaging platform — channels for teams, direct messages, threads for focused discussion, and huddles for quick voice/video calls. Slack Connect lets you message people at other companies directly through Slack instead of email.
Slack Canvas is a built-in document editor for notes and wikis right inside channels. Workflow Builder lets non-technical users automate repetitive tasks without writing code.
The App Directory has 2,600+ integrations — connect Google Drive, Salesforce, Jira, GitHub, or basically any tool your company uses.
Zoom
Zoom Meetings is the core — video calls that actually work. Zoom Webinars handles large-scale events with up to 50,000 attendees.
Zoom Phone is a full cloud-based phone system replacing traditional office phones. Zoom Rooms turns physical conference rooms into one-click video meeting spaces.
Zoom Contact Center competes with established call center software. Zoom Team Chat is their Slack/Teams competitor.
Zoom Whiteboard is a collaborative digital canvas. Zoom Revenue Accelerator uses AI to analyze sales calls.
And Zoom AI Companion summarizes meetings and drafts messages.
WHO BACKED THEM
Slack
Accel Partners, Andreessen Horowitz, Social Capital, GV (Google Ventures), SoftBank, Dragoneer Investment Group
Zoom
Sequoia Capital, Emergence Capital, Horizons Ventures (Li Ka-shing), Qualcomm Ventures