• Sebastiaan Heijne - Sir Dutch

About Sebastiaan

I'm a Dutch serial entrepreneur and angel investor. Over the last 15+ years I've founded seven companies across gaming, fintech, adtech, health and AI — from Gameye, multiplayer-gaming infrastructure trusted by studios like Bungie and Remedy, to my newest ventures INNER, Antbase and SHAPE in consumer health and AI infrastructure.

I've exited three of my ventures — Tail (acquired by Quantum Group), Signkick (merged with LiveDOOH) and WEBIQ — so I know the full arc first-hand: starting from nothing, fighting through the hard middle, and reaching a successful exit.

As an angel I've backed 56 startups, getting in early on Revolut, Kraken, Monzo and Moonpay. I work with founders on what actually moves the needle — fundraising, growth, focus, and the board-level calls that make or break a company.

But after all these years, the thing I value most isn't any single company — it's the network. I've built deep relationships with hundreds of the best people in tech: investors, founders and operators who have done it before. That network is the most valuable asset you can have as an entrepreneur, and helping you navigate it — the right introduction, the right advice, at the right moment — is where I can make the biggest difference.

Connect on LinkedIn
7Companies founded
3Successful exits
56Startups backed
$100B+Combined value backed

Companies I've Founded

I've built and exited companies across gaming, fintech and adtech — and I'm still building, with new ventures in health and AI infrastructure. I know first-hand what it takes to start, scale and exit.

Gameye

Global multiplayer game-server orchestration — deploy dedicated servers worldwide through a single API. Powering studios like Bungie, Remedy & Tripwire.

Founder & CEO

INNER

Personalised health-discovery platform — combining blood work, DNA and gut-microbiome analysis into one AI-driven report that tracks biological age, recovery and inflammation through a mobile app.

Founder

Antbase

Intelligent AI routing engine — a drop-in, OpenAI-compatible API that analyses each prompt and routes it to the best model across 30+ providers, cutting AI costs by ~50% while improving quality and speed.

Founder

SHAPE

A new neocloud built for AI — high-performance GPU infrastructure for training and inference at hyperscaler-beating economics. More to be announced soon.

Coming soon

Tail

Card-linked cashback & rewards app — the first built on the Open Banking data of Monzo and Starling Bank, giving automatic cashback on everyday spending.

Exited · acquired by Quantum Group

Signkick

Programmatic out-of-home (DOOH) advertising platform connecting media owners and advertisers.

Exited · merged with LiveDOOH

WEBIQ

Full-service web development & e-commerce agency building custom online stores for brands.

Exited

Portfolio

A selection of the 56 companies I've backed as an angel investor, ordered by latest known company valuation. Exited

Revolut
Kraken
Monzo
Boxabl
Moonpay
Paysend
Moneybox
Skybound
Future Planet Capital
goHenry
Plum Fintech
carwow
Simulate NUGGS Exited
Freetrade Exited
Seedcamp Fund 6
Curve Exited
Frost Giant
Anna
Crowdcube
Citymapper Exited
Republic Europe
Seedcamp Fund 5
Baanx
JustPark
crypterium
Tandem
BUX
Lemniscap
Shadow Drive
Abundance
easyGym
Unruly capital
NanoVM
Brickowner
Dog Tracker Nano
geodb
Housemartin
Eversend
Arrival
Den
WeSwap Exited
Cor3
Curated.fund
Emptyvessel
Gameroo
Glean Analytics
GlobeDX
Helix
Nude
Republic
RORO
Simtheory
Terran Biosciences
tryDuplo
Wisk
Young platform

Work with me

Looking for an advisor or board member who has founded, scaled and exited companies — and backed 56 more? If you're building something ambitious, I'd love to hear from you.