Marcel Santilli grew up in São Paulo, Brazil, and arrived at Silicon Valley not with a founding myth but with a pattern. The same content-publisher playbook - build authority first, convert second - kept working everywhere he deployed it. IBM. HP. HashiCorp. Scale AI. Deepgram. Every company, different product, same underlying logic.
The frustrating part? He had to rebuild it from scratch each time. No institutional memory. No repeatable system. Just a new blank Notion doc and a CMO title. After the fifth time doing this, he stopped and asked a different question: what if the system could be the product?
"CMOs don't want more tools their teams won't use or expensive agencies that bait and switch."
— Marcel Santilli, on founding GrowthX AIGrowthX AI, which Santilli co-founded with CTO Daniel Lopes in September 2024, sits in a gap that a lot of smart people had noticed but few had figured out how to fill. Too many AI tools require the user to become an AI expert. Too many agencies deliver strategy documents that gather dust. GrowthX calls its category "service as software" - expert-guided AI workflows that produce actual organic growth outcomes, not decks, not SaaS seats, not playbooks you can't execute.
The proof is in the ARR. By April 2025, GrowthX had reached $7.2M in revenue with a 48-person team - using only the same content methodology it sells to clients. Zero paid advertising. No outbound blitz. The company's own growth is the demo. That is either extremely confident or extremely good. In Santilli's case, it appears to be both.
The Series A, announced May 19, 2025, was led by Madrona Ventures, with Karan Mehandru (Managing Director) taking a board seat. Clients at funding time included Reddit, Webflow, Ramp, Superhuman, SentinelOne, Airbyte, Udemy, Abnormal Security, Vapi AI, and Homebase - a list that skews toward companies that care deeply about organic acquisition and are technical enough to appreciate the AI-first approach.
Before GrowthX, Santilli spent his final year as CMO at Deepgram doing something unusual for a marketing executive: encoding marketing expertise into AI workflows, hour by hour, over 1,000 hours total. The results were striking - 24x traffic growth, 4x revenue increase, 3,000 pages of content produced in three months, daily traffic climbing from 1,000 to 30,000. He had basically prototyped GrowthX while working at Deepgram.
Before he launched anything, Santilli ran workshops for 170+ people. Every single attendee said some version of the same thing: "This is exactly what we need - but we don't have the bandwidth to implement it." That sentence became the company thesis. Not a product insight, not a market gap analysis. A room full of people telling him exactly what was wrong.
The observation that unlocked GrowthX was deceptively simple: most AI tools put the burden of expertise on the user. You have to know what to ask, how to structure prompts, how to evaluate outputs, how to turn a draft into a published asset that ranks. Santilli had spent 15 years accumulating that expertise, and he'd just spent 1,000 hours encoding it into systems. The question was whether that encoded judgment could scale - whether the messy, expert-dependent middle of content marketing could become software.
Santilli's career didn't start in growth marketing. It started in publishing - or at least, it started with the insight that the best marketing is publishing. At IBM, where he held multiple digital marketing leadership roles from 2009 to 2013, he helped launch SecurityIntelligence.com. The bet: instead of buying advertising, become the authoritative destination for your audience's most important questions. Year one, SecurityIntelligence generated $50M in pipeline from under $1M in investment. IBM's then-radical idea - be a publisher, not an advertiser - became one of its highest-ROI marketing channels of the decade.
He took the playbook to HP's enterprise division, co-founding TechBeacon - a technology media property backed by HPE that grew to 1 million monthly organic visitors and 200,000 newsletter subscribers. One thousand contributors. Twenty articles per week. TechBeacon became the top lead source for its business unit. What IBM had done with security content, HP was now doing with developer and IT content. The pattern was becoming clear.
At HashiCorp, Santilli served as Head of Digital, Brand, Revenue Marketing, and GTM Operations during one of the fastest growth periods in DevOps history. The company went from $6M to $100M ARR in approximately two years. At ServiceTitan - now a multibillion-dollar company - he helped build the content strategy as VP of Growth Marketing. At Scale AI, as CMO, he created Transform X: a conference that brought 10,000 attendees, featured Sam Altman and Andrew Ng, generated $100M in pipeline, and cost less than $100,000 to produce. That math - $100M return on a $100K event - is the clearest single data point for understanding how Santilli thinks about leverage.
All figures from public sources including VentureBeat, Latka, GrowthX blog, and podcast interviews.
Each stop taught the same lesson in a different company's clothes - then Santilli turned the lesson into software.
"You work for the AI, not the other way around. You're the one endlessly feeding it context."
— Marcel Santilli"I've been fired 3 times and I'm pretty good at my job."
— Marcel Santilli, on CMO tenure and impossible expectations"The future isn't AI replacing experts. It's AI turning your organization's best thinking into repeatable systems."
"Companies don't need another AI tool collecting dust or a playbook they can't execute. They need a partner powered by AI but guided by experts."
"CMOs don't want more tools their teams won't use or expensive agencies that bait and switch."
"You work for the AI, not the other way around. You're the one endlessly feeding it context."
"It's hard, I don't think we figured it out. Humans are hard, man."
"This is exactly what we need - but we don't have the bandwidth to implement it."
GrowthX AI positions itself in the gap between SaaS (a seat you buy but can't fully use) and agencies (a retainer that generates decks). The "service as software" model delivers expert-guided AI workflows - human judgment encoded into repeatable systems that produce real content outcomes: rankings, traffic, backlinks, leads.
The pricing is not cheap ($18,000/month for full service), and that's intentional. The clients are B2B companies with genuine organic growth ambitions - companies like Reddit, Webflow, and Ramp that understand the value of content-led growth and don't want to hire, train, and manage a team to execute it.
Santilli is a frequent podcast guest and speaker on AI-native marketing, service as software, and organic growth strategies.