90 Interviews in 90 Days: How Nebulock Hit $25M Series A

Damien Lewke had $40 in his bank account when he started Nebulock. Two years later, he closed a $25M Series A. Between those two moments: relentless customer discovery, a year of design partnerships, and an enterprise sales process built one painful POC at a time.

Key Facts

• Time from founding to Series A: 2 years (Damien Lewke)
• Series A raise: $25 million (Pablo Srugo)
• Customer interviews completed pre-product: 90 interviews in 90 days (Damien Lewke)
• Design partner conversion rate: 100% converted to paying customers (Damien Lewke)
• Fortune 500 POC-to-close timeline: 6 weeks (Damien Lewke)

Why Customer Discovery Comes Before Everything Else

Customer discovery should happen before you build anything. Damien's 90-interview sprint revealed that his original system architecture was entirely wrong — saving months of wasted engineering and misdirected capital before a single line of production code was written.

When Damien left his job to start Nebulock, his first move wasn't to write code or build a pitch deck. He launched what he calls the 'ninety in ninety' — 90 customer interviews in 90 days, modeled on the principles from the book The Mom Test. The goal wasn't to validate his idea. It was to understand the problem deeply, without leading witnesses.

He built a spreadsheet of targets from his own LinkedIn and his network's connections, then sent short, punchy emails — never more than 50 words — offering prospects a chance to 'get their fingerprints all over the idea.' According to Damien, his conversion rate on cold outreach was north of 70%. The ask was simple: 15 to 30 minutes, no pitch, just questions.

The payoff was enormous. Damien discovered that his original plan to integrate with a system called the SIM was off base — the product needed to plug into an entirely different tech stack. A second system he planned to build turned out to add zero customer value. Without those 90 calls, he would have built the wrong product entirely.

"Be obsessed with the problem and not inherently your solution. Because your solution will evolve and change over time." — Damien Lewke

"I had core assumptions that were very wrong. I'm very glad that I did the discovery because it got me to the right place." — Damien Lewke

• Email outreach: under 50 words, clear give-get, warm intros where possible.
• Call structure: top priorities → current investments → stack-rank the problem → what should a solution look like?
• Always end by asking for an introduction to someone else in their network.
• Evolved later calls to include pricing, budgeting, and business value metrics.

How to Build a Design Partner Program That Converts to Revenue

Structure design partnerships in phases — architecture feedback first, then deployment feedback, then feature design — and require 30 minutes of weekly commitment. Damien's phased approach resulted in every single design partner converting to a paying customer.

Design partnerships are common, but most founders treat them as a binary: you're in or you're out. Damien built a three-phase model that matched the maturity of the product. Early on, partners were 'architecture partners' — giving feedback on concepts before anything was deployable. Once the product was live, feedback shifted to deployment experience and usability. In the final phase, partners became 'feature design partners,' helping shape specific capabilities in exchange for a promised discount at launch.

The weekly commitment was non-negotiable: 30 minutes, every week, no exceptions. Damien's litmus test was simple. If a prospect wouldn't give him 30 minutes a week, they didn't value the problem enough to be a useful partner. That filter kept the program tight and the feedback high-signal.

The result was extraordinary. Nebulock ran approximately a full year of design partnerships before converting to paid revenue — a deliberate choice. Damien wanted the transition to paid to feel like a 'slam dunk and no-brainer' for customers rather than a hard sell. When revenue did turn on, every design partner converted.

"I'm actually excited to say that every single one of our design partners converted to a paying customer and that was a really, really exciting moment." — Damien Lewke

"Don't overcomplicate it. Ask for time, they'll commit to time. You build a relationship and eventually, if what you do is valuable, they will pay for it." — Damien Lewke

Building a Repeatable POC Playbook That Closes Fortune 500 Deals

A repeatable POC process needs three elements: defined scope and timeline, pre-agreed success criteria tied to a purchase decision, and executive sponsor access — not just a champion. Nebulock's one-month POC requiring two customer hours closed a Fortune 500 in six weeks.

The design partner year gave Nebulock something most early-stage startups don't have when they go to market: a proven POC playbook. By the time Nebulock engaged the Fortune 500 that became its product-market fit proof point, the team had iterated through multiple POC structures and knew exactly what worked. The result was a one-month process requiring only two hours of the customer's time — and a finding escalated to the CISO within a day and a half.

That finding exposed a genuine security gap: an AI agent touching a production database it should never have accessed, with the account creation trail fully traced. Budget was earmarked without prior negotiation. The CISO became an internal champion. The deal closed in six weeks from POC start.

But Damien is candid about the failures that preceded this win. Earlier POCs dragged on for three to six months, not because the product failed, but because of three avoidable mistakes: no defined timeline, no pre-agreed success criteria linked to a purchase, and — most critically — no mapping of the procurement process. His hardest-won lesson: your champion can't push procurement. You need to find the executive sponsor who can, and you need to understand the procurement machinery before the POC starts, not after.

"Always have an executive sponsor and ask about the procurement process. It's okay — I have been a customer before of security solutions and I was not always thrilled with my procurement process." — Damien Lewke

"By the time we hit that Fortune 500, we had a month long POC process that required two hours of customer time. We had a playbook that we knew how to run." — Damien Lewke

• Set timeline and success criteria at POC kickoff — don't leave the close open-ended.
• Identify an executive sponsor in addition to your champion.
• Ask about procurement process upfront; try to parallelize legal paperwork.
• Nail your Data Processing Agreement (DPA) before deployment, not after.

Going Solo: What First-Time Solo Founders Need to Know

Solo founding works when you're obsessed with the problem, not the solution. Damien validated his conviction with a simple test: would he tackle this problem for $0? If yes, jump. Then hire heads of function earlier than a co-founded team would, and give them real agency.

Damien made the decision to go solo with a single question: 'If I made $0 and all I could do was tackle this problem, would I do it?' When the answer was yes, he quit. No co-founder, no safety net — just $40 in a newly opened bank account and a 30-page manifesto on why the security market was broken.

That manifesto, not a pitch deck, led to Nebulock's $2.4M pre-seed from Decibel Ventures. Bain Capital Ventures preempted the seed round at the end of 2024, bringing total pre-Series A funding to $8.5M. The raises were grounded in customer data from the 90-in-90, not financial projections.

On building the team, Damien's philosophy is needs-based hiring with an eye around the corner. He brought in a Head of Engineering when the team was nine people — before things were broken — so the new leader could grow into the role rather than fight fires. His rule: one well-placed person beats four poorly placed people. And for early hires, compelling equity and compensation matter because the risk is real.

"Your fundamental job as a founder is two things. Number one, create an environment where people feel seen, heard, and empowered to do their best work. And number two, to de-risk the business." — Damien Lewke

"I've continuously hired myself out of a job — hired myself out of the marketing leader role — and we've got an amazing head of engineering, product, sales, customer success." — Damien Lewke

POC Approach: What Dragged vs. What Worked