Software Engineer (m/f/d)

Cello is the Revenue Growth Infrastructure for modern digital businesses — turning word-of-mouth into a systematic, measurable growth channel for the AI era. Category leaders like Typeform, Miro, and Veed use Cello to accelerate their growth flywheel. TL;DR• Seed, GrowthTech • Remote-first, Europe-based (must be within CET +/-3 hours) • Competitive salary + eVSOPS Why Cello• $10.3M raised from top-tier investors, 30+ new customers every month • Small team — you'll shape how we build, not just execute tickets • Founding team of serial founders and operators from Twilio, Wise, and Skype • We adopt AI tools where they actually help — because our customers do too • Remote-first with regular team meetups across Europe What We’re BuildingWe help SaaS companies turn their users and partners into a sales channel through referrals, sharing, and recommendations - 10M+ end users interact with our system every month. Our widgets live inside customer products, which means your code runs in environments you don't control. On top of that: APIs that customer developers integrate against, and a portal where customers manage their campaigns and analytics. Under the hood: attribution across complex user journeys, AI-based recommendation engines, multi-tenant infrastructure serving hundreds of customers, scaling millions of events. Deeper than you'd expect from a referral tool. Our product is integrated by customer developers - and that world is changing fast. The people building against our APIs and widgets range from corporate engineering teams to solo founders using AI coding agents. Keeping up with how developers work today, and making sure our product fits into all of those workflows, is one of the more interesting challenges here. What you will do:• Work with the following stack: React · Typescript · NestJS · Python · AWS • You'll start with well-scoped tasks and ramp up from there - we don't expect you to know everything on day one. • Build features, fix bugs