Slack

Stripe

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.

Stripe

Stripe charges a flat 2.9% + $0.30 per transaction. That's it.

No setup fees, no monthly fees, no hidden charges. The simplicity is the product.

When a customer pays on a website using Stripe, Stripe handles everything — fraud detection, currency conversion, bank transfers, tax calculation, compliance. The merchant just sees money arrive in their account.

On top of the core payments, Stripe has built an entire financial infrastructure stack. Billing for subscriptions, Connect for marketplace payments, Atlas for incorporating a company, Issuing for creating virtual cards, Treasury for banking-as-a-service, and Radar for fraud prevention.

They're basically building the financial plumbing for the entire internet.

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."

Stripe

Patrick Collison was 19. His brother John was 17.

They had already built and sold a company — Auctomatic, an eBay auction tool — for $5 million while still teenagers in Limerick, Ireland. Patrick went to MIT, John went to Harvard, and they both dropped out because they had a better idea.

The idea was embarrassingly obvious in hindsight. In 2010, accepting payments on the internet was a nightmare.

You had to get a merchant account, negotiate with a payment processor, deal with a gateway provider, handle PCI compliance, and write thousands of lines of code. It took weeks or months.

The Collisons thought it should take five minutes.

They built a simple API — seven lines of code — that let any developer start accepting credit card payments immediately. No merchant account.

No paperwork. No phone calls with banks.

Just paste seven lines of code and you're in business. They originally called it /dev/payments, then changed it to Stripe in 2011.

Peter Thiel and Elon Musk — the PayPal mafia — were among the first investors. Sequoia and Andreessen Horowitz piled in soon after.

The Collisons had built exactly what every developer on Earth had been wishing for.

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.

Stripe

Stripe grew almost entirely through developer love. They didn't hire a sales team for years.

They didn't run ads. They just built the best developer documentation anyone had ever seen and let word of mouth do the rest.

The developer-first strategy was deliberate. The Collisons realized that in a startup, the developer usually decides which payment provider to use.

If you make the developer happy, you win the company. Stripe's API documentation became legendary — clear, beautiful, with working code examples in every language.

They also grew by growing with their customers. Early Stripe customers included tiny startups that later became giants — Lyft, DoorDash, Instacart, Shopify.

As those companies scaled to billions in revenue, Stripe's processing volume scaled with them. Stripe didn't need to acquire new customers because its existing ones kept getting bigger.

The international expansion was methodical. Instead of launching everywhere at once like Uber, Stripe carefully added country after country, making sure each one worked perfectly with local payment methods, currencies, and regulations.

By 2024 they were processing payments in 195 countries.

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.

Stripe

Valuation whiplash. In 2021, Stripe hit a peak valuation of $95 billion during the fintech boom.

By 2023, they had to mark it down to $50 billion during the tech correction — a 47% drop that made headlines everywhere. Employees who had been paper millionaires suddenly weren't.

The valuation has since recovered to $91 billion after a secondary share sale in 2025, but those two years were rough for morale.

Competition is relentless. Adyen, the Dutch payments company, has been eating into Stripe's enterprise market.

Square (now Block) competes on the small business side. PayPal is everywhere.

New fintech players pop up constantly. The payments business has razor-thin margins and everyone is fighting for the same 2.9%.

Going public is the elephant in the room. Stripe has been expected to IPO for years.

Investors, employees, and the media keep asking when. The Collisons have consistently said they're in no rush, but with $8.7 billion raised and thousands of employees holding stock options, the pressure to provide liquidity is enormous.

As of 2025, they've opted for secondary sales instead of a public offering.

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.

Stripe

Stripe Payments is the core — accept credit cards, debit cards, Apple Pay, Google Pay, and 135+ payment methods in 195 countries. Stripe Connect lets marketplaces and platforms pay out to sellers (Shopify, Lyft, DoorDash all use it).

Stripe Billing handles subscription and recurring billing. Stripe Atlas lets you incorporate a US company from anywhere in the world — fill out a form, get a Delaware C-corp, bank account, and tax ID in days.

Stripe Radar uses machine learning to block fraud in real time. Stripe Treasury lets platforms offer banking services to their customers.

Stripe Tax automatically calculates and collects sales tax in every jurisdiction.

Slack

Accel Partners, Andreessen Horowitz, Social Capital, GV (Google Ventures), SoftBank, Dragoneer Investment Group

Stripe

Peter Thiel, Elon Musk, Sequoia Capital, Andreessen Horowitz, General Catalyst, Founders Fund, Tiger Global, GV (Google Ventures), Goldman Sachs, Baillie Gifford