Hi — we're Hypefy, a Croatian-based start-up.
We're building AI agents that run influencer marketing end-to-end: campaign creation, creator selection, outreach, content checks, payments, reporting — all automated, all at scale.
This is already live, used by real brands and creators across more than 35 countries. Now we want to scale globally, and we need a strong senior engineer who takes ownership of hard problems and helps the team level up.
You'll own and evolve core systems across the platform — from architecture decisions to production incidents to shipping new capabilities.
Backend (Primary Focus)
Design, build, and maintain backend services in Node.js
Own features end-to-end — from scoping to production to monitoring
Architect and operate background job systems (queues, workers, retries, fallbacks)
Ship AI-driven features with proper guardrails: schema validation, retries, safe fallbacks
Harden and monitor third-party integrations for reliability at scale
Make MongoDB fast and predictable through solid data models and indexing
Use Redis / BullMQ for queues, caching, rate limits, and transient state
Frontend
Build and refine UI features in React — mobile and web
Surface complex system state clearly (background jobs, AI progress)
Collaborate closely with design and product on workflows that aren't simple
Platform & Reliability
Drive observability improvements so debugging doesn't feel like guesswork
Contribute to scalability initiatives — regional deployments, throughput
Lead incident response and postmortems
Help raise the technical bar across the team
Small, senior-leaning engineering team
High ownership, low bureaucracy
Direct access to product and founders
We use AI coding tools heavily — for reviews, small features, and day-to-day productivity
Required
5+ years of backend engineering experience, strong Node.js
Deep comfort with async systems, background jobs, and failure scenarios
Track record of owning features and systems end-to-end in production
Strong instincts for technical trade-offs — you know when to move fast and when to slow down
Experience working with large-scale databases (schema design, indexing, query performance), with the ability and willingness to ramp up quickly on MongoDB
Clear communication and a genuine ownership mindset
Experience mentoring or raising the bar on a team
Nice to Have
Experience with AI / LLM integrations in production
Experience with MongoDB (schema design, indexing, performance)
Experience with React
Prior work in SaaS, marketplaces, or automation-heavy platforms
Experience with advanced AI coding workflows
You'll work on complex, real systems — not greenfield prototypes — and make them genuinely better
Small, agile team where senior engineers have real architectural influence
A live AI product, in active use by customers, with actual production complexity
Direct impact on scaling decisions as we grow into new markets