Who We Are

Engineering that keeps up with your growth.

We join your team, own the engineering, and ship weekly. 15 years in production subscription apps: RevenueCat, Superwall, Adapty, React Native.

15+

Years in Production

50+

Subscription Apps

Multiple

Exits through acquisition

Leadership.

Senior engineers and product leaders with deep experience in subscription app infrastructure, mobile development, and product strategy.

Ken Vermeille

Ken Vermeille

CEO & Founder

15+ years building production subscription apps. React Native, iOS, Android, RevenueCat, Superwall. Embedded with PE portfolio companies and high-growth startups.

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Irem Gultekin

Irem Gultekin

Director of Product Management

Product strategy and execution with experience at Amazon, Apple, and high-growth startups. Leads discovery and roadmapping with a focus on clarity, velocity, and measurable outcomes.

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Mark Montgomery

Mark Montgomery

Creative Director

Brand and product design systems for Spotify, Apple, and global enterprise clients. Leads design with a focus on systems thinking, conversion clarity, and craft.

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Why Vermillion Exists.

Vermillion exists because marketing-first subscription app teams deserve engineering that keeps pace with their growth. The fastest operators (running paywall experiments, testing pricing, launching campaigns) shouldn't be bottlenecked by an engineering team that can't ship weekly or doesn't understand how RevenueCat webhooks behave in production.

We've been embedded in subscription apps for 15 years. Our team has shipped 50+ apps, multiple exits through acquisition, and supported fundraises totaling $27M. That experience taught us one thing: the teams that win aren't the ones with the most engineers. They're the ones where marketing and engineering move at the same speed.

What we do is specific and rare. We embed as your engineering team, own the mobile stack, and ship weekly. React Native, Expo, TypeScript. RevenueCat, Superwall, Adapty, deeply integrated, not just installed. We're not a vendor you file tickets with. We're the team that answers Slack messages and ships on Thursdays.

Our Proof.

15+

Years shipping production subscription apps

50+

Subscription apps built and maintained

1M+

Users across our client products

$27M

Raised by founders we've partnered with

Deep hands-on experience with React Native, RevenueCat integrations, Superwall paywall optimization, and Adapty infrastructure. We measure success by shipping velocity and MRR growth, not just code quality.

Our Values.

Speed

Without sloppiness. We move fast and never let pace become an excuse for quality.

Excellence

Without ego. We deliver quality that stands up to scrutiny, in code and in communication.

Integrity

We say what needs to be said. If something is going to break, you hear it from us first.

Commitment

Beyond launch. We're embedded for the long term. Our incentives are aligned with yours.

Delight

In the details. We care about how the product feels, not just whether it ships.

Beauty

In codebases that are satisfying to maintain. Good architecture is beautiful architecture.

Our Guarantee.

We ship weekly. Every week. That's the commitment: not a promise about what we'll prevent, but a commitment to what we'll deliver.

Ready to move at the speed your marketing demands?

15 minutes. No pitch. We'll learn about your stack and tell you honestly if we're the right fit.

Talk to our team