Bjarne Christiansen
Founder and technologist. I write about building companies from the inside — startup fundamentals that hold up under pressure, what fundraising looks like from both sides of the table, and what the Nordic ecosystem gets right that Silicon Valley misses.
Co-founded Realm (YC S11) — a mobile database that reached 2 billion device installs before its acquisition by MongoDB in 2019. Previously spent over a decade at Nokia building software for hundreds of millions of devices. Currently CTO at Float. What I'm focused on now →
Writing
What Y Combinator Actually Taught Me About Resilience
The YC S11 batch was Paul Graham's artisanal era — intimate dinners, direct access, a different quality of feedback than what most founders get. What I took from three months in that environment wasn't the tactical advice. It was a specific, usable model of what founder resilience actually looks like — and what it doesn't.
Founder/Market Fit: A Three-Question Self-Audit Before You Raise
Investors talk about product-market fit constantly. They talk about founder-market fit much less, but they're evaluating it in every meeting. Here's the three-question framework I've developed from sitting on both sides of the table — and how to audit yourself against it honestly before you start a fundraising process.
What YC Taught Me That Actually Applies to Building in the Nordics
Y Combinator's model was designed for a specific context: young founders, fast iteration, San Francisco network effects, three months to Demo Day. Some of what it teaches transfers perfectly to Nordic building. Some of it is actively misleading. Here's the filter I use.
The Six Board Slides That Actually Matter
Most board decks are theater. Founders present optimistic narratives; board members ask polite questions; the meeting ends and everyone has learned approximately nothing. After being on both sides of the table, here are the six slides that make a board meeting genuinely useful — and why most founders avoid them.
- Part 4 of "Building for Regulated Industries"
Why Compliance Technology Is About to Get Interesting
Pharmaceutical compliance software hasn't changed fundamentally in twenty years. AI is about to force a reckoning. But the hard problem isn't the AI — it's that the compliance data model itself is broken. Here's what actually needs to change, and what the next generation of compliance infrastructure looks like.
What the MongoDB Acquisition Actually Felt Like: Notes from the Founder Seat
We built Realm for eight years, raised $40M, reached 2 billion installs, and then got acquired by MongoDB. Here's what the acquisition process actually looks like from the founder side — the parts that surprised me, the mistakes I made, and what I wish someone had told me going in.
How Realm Works: The Database Architecture Behind 2 Billion Installs
A technical deep-dive into the Realm database engine: MVCC without locks, zero-copy reads via memory mapping, live objects, and why we had to build a custom sync protocol from scratch. What we got right, what we got wrong, and what I'd do differently.
Nordic Founders Fundraising in the US: What Actually Works
The US venture capital market is the deepest pool of early-stage capital in the world. Nordic founders who navigate it successfully tend to do three things differently from the ones who don't. Here's what those things are, from someone who raised $40M in the US as a Danish founder and has since helped others do the same.
Why I Built Cohera: The Problem with Disconnected Quality Systems
Pharmaceutical companies run dozens of quality systems that don't talk to each other. After building a mobile database used by billions, I saw an opportunity to solve this problem with modern technology. Here's the story of why I started Cohera.
- Part 1 of "Building for Regulated Industries"
Building for Regulated Industries: Lessons from Pharma Tech
Regulated industries like pharmaceutical, medical devices, and life sciences present unique challenges for software builders. Here's what I've learned about building enterprise software where compliance isn't optional.
- Part 2 of "Building for Regulated Industries"
AI in Compliance: Automation Without Breaking Audit Trails
Everyone's talking about AI transforming industries. But in regulated environments like pharma, the question isn't whether AI can help—it's whether AI can help while maintaining the audit trails and human oversight that regulators require.
The Decade Nobody Writes About
Before Realm, before Y Combinator, before any of the founder narrative — there was over a decade at Nokia. Software configuration management, build system tooling, infrastructure for hundreds of millions of devices. The unglamorous, foundational work that I've never written about, and that I now think was the most important decade of my career.
The Integration Layer Approach: Why Rip-and-Replace Fails in Regulated Industries
The conventional wisdom in enterprise software is to consolidate systems. In regulated industries, this approach consistently fails. Here's why an integration layer strategy works better, and how we designed Cohera around this principle.
- Part 3 of "Building for Regulated Industries"
From YC to Series A: Building Enterprise Software for Pharma
My first startup went through Y Combinator and raised $40M. My second is building for pharmaceutical companies. The fundraising playbooks couldn't be more different. Here's what I learned about raising for enterprise software in regulated industries.
Ontology-Driven Architecture for Compliance Software
When building software that connects multiple enterprise systems, the data model becomes your most important architectural decision. Here's how we use ontology-driven design at Cohera to create a unified layer across disparate quality systems.
The Three Questions Investors Ask When the Traditional Signals Aren't There Yet
After sitting on both sides of the table — raising $40M as a founder and helping tier-one VCs evaluate early-stage deals — I've noticed that the investors who are right at the early stages aren't pattern-matching on traction. They're pattern-matching on three specific things. Here's what they are and how to test yourself against them before you pitch.
Dilution Without Regret: What I Wish I'd Known About Cap Tables Before Raising $40M
After raising $40M across three rounds and watching the cap table evolve from a simple three-person founding team to something requiring a lawyer to interpret, here's what I actually learned about dilution, preference stacks, and the decisions that compound in ways founders don't model until it's too late.
PMF Is Not One Number
The product-market fit conversation in most startups is binary: do you have it or not? That framing is wrong, and the wrong framing leads to wrong decisions. Product-market fit is a spectrum with specific diagnostic signals at each stage — and knowing where you are changes what you should be doing next.
Default-Alive, For Real: The Calculation Every Founder Should Run Monthly
Paul Graham wrote about default-alive in 2015. Most founders read it and nodded. Very few actually model it. Here's the specific calculation, why it matters more than runway, and what changes when you treat it as a monthly discipline rather than a one-time analysis.
Why Building in Denmark Is a Secret Advantage (That Most Danish Founders Don't Use)
A Danish founder who spent 13 years in Silicon Valley and came back to build in Copenhagen. What I found when I returned is not what I expected — and the advantage is larger than most Nordic founders realize, mostly because they're too close to it to see it clearly.
The Night Seed Funding Changed Forever
I was in the room at YC S11 when Yuri Milner and Ron Conway walked in and announced that every company in the batch would receive $150,000 as an uncapped SAFE — no negotiation, no diligence. The palpable shock in the room that evening changed founder psychology overnight. Fifteen years later, it's still shaping how startups are funded.
The Hardest Thing I've Done Professionally
We scaled Realm to 68 employees, then cut to 24 in a single round when the fundraising market tightened. What those 44 conversations taught me about the real cost of capital dependency — and the principle I've built every company around since.
What Letting 44 Engineers Go Taught Me About Building Teams
We went from 68 engineers to 24 in a single round of cuts. It was the hardest thing I've done professionally. What came out of it permanently changed how I think about hiring, team structure, and the relationship between capital and headcount.
Why I Started Requiring Engineers to Write Before They Coded
At Nokia, writing was how you got anything done in a large organization. At Realm, we used the same discipline differently: as a decision-making tool, not a bureaucratic process. The writing practice that actually changed how our team built.
Product Vision Without Engineering Buy-In Is Just a Wish
In 2012, I asked our team to throw away a working codebase and start over. Getting engineers to believe in the vision as fully as I did — not just execute on it — was the hardest leadership problem I'd faced to that point. What I learned from that experience about the gap between communicating a vision and transferring it.
The Scalability Mistake Most Startups Make Before They Have Anything to Scale
Scalability planning is one of the most misunderstood activities in early-stage software. After a decade building systems for hundreds of millions of Nokia devices and a database in 2 billion apps, here's what I've learned about when architectural decisions actually matter — and when they don't.
What Building a Database for Two Billion Devices Taught Me About Data
Three copies of every piece of data, a custom C++ storage engine designed from scratch, and 80x performance gains that developers described as magic. What actually building at data scale revealed about the problem most engineering teams get wrong.
Lessons from Building Developer Tools: What I Learned at Realm
Building tools for developers is a unique challenge. They're your harshest critics and your best advocates. Here are the lessons I learned co-founding Realm, a mobile database that reached millions of developers.
Technical Due Diligence: What Investors Actually Look For
Having been on both sides of the table—as a founder being evaluated and as an advisor helping investors assess startups—here's what technical due diligence actually examines and how to prepare for it.
What a Fractional CTO Actually Does: A Practical Guide
The fractional CTO role is often misunderstood. It's not about part-time leadership—it's about bringing full-time expertise to companies that need strategic technical guidance without the overhead of a full-time executive. Here's what the role actually entails.
Data at the Edge: The Rise of Edge Computing in Industrial IoT
Edge computing is transforming the industrial IoT landscape by bringing data processing closer to the source. This post examines the benefits of edge computing, including improved performance, reduced latency, and enhanced security, and discusses how businesses can leverage edge computing strategies to optimize their industrial IoT operations.