AT A GLANCE

Cloudflare
Sierra
2009
Founded
2023
San Francisco, California
HQ
San Francisco, USA
$332 million
Total Raised
About $1.6 billion
Matthew Prince, Michelle Zatlyn, Lee Holloway
Founder
Bret Taylor and Clay Bavor
Cybersecurity
Type
AI
Public (NYSE: NET)
Status
Private — $15.8B valuation (May 2026)

FUNDING HISTORY

Cloudflare

Seed2009
$2M raised
Series A2011
$20M raised
Series B2012
$50M raised
Series C2014
$50M raised
Series D2015
$110M raised$3.2B val.
IPO2019
$525M raised$4.4B val.

Sierra

Seed2024
$110M raised$1.0B val.
Series A2024
$175M raised$4.5B val.
Series B2025
$350M raised$10.0B val.
Venture Round2026
$950M raised$15.8B val.

BUSINESS MODEL

Cloudflare

Cloudflare operates on a freemium model with usage-based pricing. The free tier provides basic CDN, DDoS protection, and SSL for any website — this is how millions of sites use Cloudflare without paying a cent.

Paid plans start at $20/month (Pro), $200/month (Business), and custom enterprise pricing for large organizations.

The free tier is the growth engine, not charity. Every free website that routes through Cloudflare adds data to the network — more traffic patterns to analyze, more attacks to learn from, more threat intelligence to feed the machine learning models.

Free users make the paid product better.

Enterprise contracts are where the real money lives. Large organizations pay six and seven figures annually for advanced security, performance, and compliance features.

Revenue reached $1.67 billion in 2024 and kept compounding at roughly 28% a year. The company has been approaching profitability with improving margins.

Sierra

Companies pay Sierra to run their customer service with AI agents instead of hiring rooms full of humans. The agent talks to your customers over chat.

It answers questions. It processes returns.

It updates subscriptions. Here is the clever part.

Sierra charges based on outcomes, not seats. Brands pay when the AI actually resolves a problem, not just for having the software installed.

That pricing is unusual. Most software charges a flat monthly fee no matter what.

Sierra only gets paid when the bot does the job.

HOW THEY STARTED

Cloudflare

The origin story starts with Project Honey Pot, a free open-source project that Matthew Prince created in 2004 to track online spammers and hackers. The project grew to track millions of malicious IP addresses, and the Department of Homeland Security started using the data.

But Prince noticed something: he had all this threat intelligence and no good way to help website owners actually use it.

At Harvard Business School in 2009, Prince teamed up with Michelle Zatlyn for a class project exploring how to turn that threat data into a product. Their professor gave them a B — which Prince has jokingly called the most expensive B in HBS history, given what the company became.

They brought in Lee Holloway, a brilliant but unconventional systems programmer Prince had worked with previously, as the third co-founder and technical architect.

Cloudflare launched publicly at TechCrunch Disrupt in September 2010 with a bold pitch: sign up for free, change your DNS, and Cloudflare will make your website faster and more secure. No hardware to install.

No software to configure. Just a DNS change.

In the first day, thousands of websites signed up. The simplicity was the product — in an industry where security meant expensive appliances and complex configurations, Cloudflare said "just point your domain at us and we'll handle it."

Sierra

Bret Taylor had already done the impossible twice. He co-created Google Maps.

He later became co-CEO of Salesforce, chaired Twitter's board during the messy Elon Musk takeover, and became chairman of OpenAI in late 2023. Clay Bavor spent 18 years at Google, most recently running its Labs group.

The two friends left their big jobs in 2023 to build something together. They picked customer service on purpose.

It is the least glamorous corner of software. Their logic was simple.

Companies hate their support costs. Customers hate waiting on hold.

AI that actually resolves problems could fix both sides at once. They launched Sierra in February 2024 with $110 million from Sequoia and Benchmark.

HOW THEY GREW

Cloudflare

Cloudflare grew by being free. The free tier removed every barrier to adoption.

A blogger in India and a Fortune 500 company could both sign up in five minutes. This created a massive installed base that generates word-of-mouth, training data, and upsell opportunities.

The developer community became the second growth engine. Cloudflare Workers turned the company from a security vendor into a cloud computing platform.

Developers build entire applications on Cloudflare's edge network, which creates deep technical lock-in. Once your application runs on Workers, migrating to AWS Lambda is a significant engineering effort.

Strategic pricing warfare accelerated commercial adoption. When Cloudflare launched R2 storage with zero egress fees, it directly attacked Amazon S3's most hated pricing model.

The "Bandwidth Alliance" partnered with cloud providers to eliminate data transfer fees. These moves positioned Cloudflare as the anti-AWS — the cloud company that doesn't nickel-and-dime you.

Sierra

Sierra went straight for big brands, not tiny startups. SoFi, Ramp, ADT, Sonos and Brex signed up early.

By 2026 it said more than 40% of the Fortune 50 were customers. The trick was trust.

Enterprises are terrified of an AI bot going rogue and insulting a customer. So Sierra built guardrails and let each company control exactly how the agent behaves.

Bret Taylor's contacts did the rest. When the chairman of OpenAI calls a Fortune 500 CEO, they pick up.

Sierra hit $100 million in annual recurring revenue in November 2025, seven quarters after launch, and $150 million by February 2026. In April 2026 it launched Ghostwriter, which builds and deploys a new agent from a plain-English description.

THE HARD PART

Cloudflare

AWS, Google Cloud, and Microsoft Azure are simultaneously partners and competitors. Cloudflare's network sits in front of these clouds, which makes the cloud providers uncomfortable.

As Cloudflare expands into compute (Workers), storage (R2), and databases (D1), the competitive overlap grows. The cloud providers could theoretically build or acquire similar capabilities and bundle them for free.

Profitability pressure is real. Cloudflare has prioritized growth over profits, spending aggressively on network expansion and R&D.

Operating margins have been negative for most of the company's public life, though they've been improving. Investors have tolerated this during growth-stock mania but patience may not last forever.

Content moderation controversies arise periodically. As a company that provides infrastructure to millions of websites, Cloudflare occasionally faces pressure to terminate service to controversial or harmful sites.

They removed 8chan after the El Paso shooting in 2019 and the Daily Stormer in 2017. Prince has described these decisions as uncomfortable, arguing that infrastructure providers shouldn't be arbiters of online speech but sometimes have no choice.

Sierra

Everyone is building AI customer service agents right now. Decagon has raised at a multi-billion valuation.

Salesforce, ServiceNow and Intercom all shipped their own agents. Sierra is not the cheap option.

It sells premium AI to giant companies that move slowly. The bigger risk sits underneath the product.

Sierra does not make its own AI models. It rents them from providers like OpenAI and Anthropic.

If those model makers decide to compete directly, Sierra's edge gets thin fast, and its co-founder chairing one of them only makes that question louder. A $15.8 billion valuation on roughly $150 million in revenue leaves almost no room for a stumble.

THE PRODUCTS

Cloudflare

Cloudflare CDN — a content delivery network spanning 330+ cities in 120+ countries that caches and serves web content from the nearest location to each user, making websites dramatically faster. Cloudflare DDoS Protection — automatic detection and mitigation of distributed denial-of-service attacks.

Has blocked some of the largest DDoS attacks in internet history, including a 71 million requests-per-second attack in 2023. Cloudflare Workers — a serverless computing platform that lets developers deploy code to Cloudflare's edge network, running applications in 330+ locations worldwide with millisecond latency.

Cloudflare Zero Trust — a complete security platform replacing traditional VPNs and firewalls with identity-based access controls for remote workforces. Cloudflare R2 — object storage that competes with Amazon S3 but with zero egress fees, saving companies thousands on data transfer costs.

Sierra

The core product is the Sierra AI agent. It is a branded customer service bot that companies deploy on their website, app, and phone lines.

It handles the boring stuff. Order tracking.

Refunds. Password resets.

Account changes. Sierra also built its own tools to test and monitor these agents so they do not make things up.

In 2024 the company added a voice version that talks to customers on the phone. In April 2026 it added Ghostwriter, a tool that builds and deploys a new agent from a plain-English description.

The whole pitch is one AI agent that carries your brand's name and never sleeps.

WHO BACKED THEM

Cloudflare

New Enterprise Associates (NEA) led the Series A. Venrock, Pelion Venture Partners, and Union Square Ventures invested early.

Fidelity, Microsoft, Google Capital (now CapitalG), and Baidu all invested in later rounds — notably both Google and Baidu investing in the same company. The September 2019 IPO raised $525 million at a $4.4 billion valuation.

The stock has since grown significantly.

Sierra

Sequoia Capital and Benchmark wrote the first checks at launch in February 2024, $110 million between them. Greenoaks Capital then led both the $175 million round in 2024 and the $350 million round in September 2025.

In May 2026 Tiger Global and Google's GV led a $950 million round at a $15.8 billion valuation, with Benchmark, Sequoia and Greenoaks back in. That takes total funding to about $1.6 billion.

That is partly the product and partly Bret Taylor. Investors bet on founders who have already built billion-dollar things.

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