Senior Software Engineer

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. What you'll work on 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 How We Work 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 What We're Looking For 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 Why Join Hypefy 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