Founding Engineer

Stealth; Stockholms kommun; On-site; Confidential; Full time

Benefits offered by this job

Equity stake

CTO path

Expert backing

Early-stage startup

Job summary

Stealth is building a next-generation AI-driven programmatic advertising platform. You will join as a Founding Engineer, partnering with the founders to design and scale the core system, impacting customers from day one.

Expect to work across the stack—from campaign UX to performance reporting—and to shape AI-enabled creative workflows and optimization logic. You will own multi-tenant architecture, security, and robust infrastructure, while collaborating with top-tier tech veterans and early

Qualifications

• 4+ years in full-stack web development with Node.js/TypeScript.
• Proven ability to design secure, multi-tenant systems.
• Experience with API-first architectures and typed contracts.
• Proficiency with Docker and containerized workflows.
• Experience writing and maintaining automated tests for production systems.
• Experience setting up cloud infrastructure (IaC).
• Product-minded and able to iterate quickly based on user feedback.

Responsibilities

• Architect and scale a multi-tenant AI-powered ad platform.
• Lead technical decisions across the stack, including UX, reporting, and performance.
• Implement AI-driven creative workflows and optimization logic.
• Own security, tenancy isolation, and clear service boundaries.
• Build CI/CD pipelines and monitoring for high-traffic APIs.
• Collaborate with founders and stakeholders to ship features rapidly.

Skills

Node.js

TypeScript

API-first design

Security

Multi-tenant systems

Testing

CI/CD

Cloud IaC

Product mindset

Tools

Next.js

Express/Fastify

NestJS

Prisma

PostgreSQL

Docker

Job description

We’re building a next-generation AI-powered programmatic advertising platform that makes high-quality, data-driven campaigns accessible to every marketer - from startups to established brands. Our platform empowers advertisers to create, launch, and optimize campaigns in minutes, with real-time budget optimization and AI-generated creatives designed to improve performance.

We’ve raised our first round, validated market demand, and are currently onboarding our first customers. You’ll be joining at the ground floor, supported by the former CTOs of unicorns and leading ad-tech companies.

Tasks

As Founding Engineer, you’ll work directly with the founders to build and scale our core platform. You’ll lead on technical decisions, architect robust systems, and deliver features that directly impact customer success. Expect to work across the stack, from campaign UX to performance reporting, with significant input into AI-based creative workflows and optimization logic.

What You’ll Work On

• Multi-tenant advertiser platform: Campaign creation, creative management, targeting, budgets, approvals.
• Reporting & attribution: Low-latency dashboards, providing near-instant performance insights with appropriate caching strategies.
• Ad spend optimization: Budget allocation, pacing, and performance improvement based on live campaign data.
• AI-powered creative generation: Automated asset creation and variation testing to maximize ROAS.
• Security & compliance: Tenant isolation, JWT-based auth, and clear service boundaries.
• Scalable infrastructure: CI/CD pipelines, monitoring, and deployment for high-traffic APIs.

Requirements

What We’re Looking For

• 4+ years in full-stack web development, with strong experience in Node.js (TypeScript).Bonus: Next.js, Express or Fastify (ideally with NestJS), and PostgreSQL (ideally with ORMs such as Prisma).
• Proven ability to design secure, multi-tenant systems.
• Comfort with API-first architectures and typed contracts.
• Proficiency with Docker and containerized development workflows.
• Experience writing and maintaining automated tests for production systems.
• Experience setting up cloud infrastructure (preferably with Infrastructure-as-Code).
• Product mindset - iterating quickly based on user feedback.

Nice-to-Haves

• Prior work in programmatic advertising, DSP/SSP integrations, or attribution.
• AI/ML integration for creative generation or performance prediction.
• Early-stage startup or founding engineer experience.
• Strong observability and scaling practices for high-throughput systems.

Benefits

Why Join Us

• Stealth with momentum: Funded, validated, and in-market with early customers.
• Big technical impact: Your decisions will shape the platform for years.
• Expert backing: Work closely with former CTOs of unicorns and leading ad-tech companies.
• Significant equity: Directly tied to company growth and success.
• Growth path: Potential to evolve into CTO as we scale.

If you’ve been waiting for a chance to be there from the start, build something category-defining, and own both code and company direction - this is it.