Senior Backend Engineer (Innovate) Who we areYubo is the Social Discovery app to make new friends and hang out online. By eliminating likes and follows, we empower our users to create genuine connections and show up as their true selves.We've pioneered a new way for Gen Z to socialize online, and with millions of active users, our goal is to redefine how we connect today and tomorrow.Our team is international, multicultural and deeply committed to its mission. As the leading platform to socialize online, we have a special responsibility to build a safe digital space for our community. Safety is embedded in our DNA, and our proactive approach focuses on user protection, support, and education. We also work closely with the broader technology industry to share our knowledge and NGOs create industry-leading child protection standards.Join us in this exciting journey and help us shape the future of social interactions!About this roleAs Yubo continues to scale and roll out its 2026 Tech organization, we’re launching a brand new Innovate squad focused on bold product bets and high-risk initiatives.This squad’s mission?Make big bets, test ambitious features, and validate them through continuous experimentation.We’re looking for a Senior Backend Engineer to join our Backend Experience team, reporting directly to Armand (Engineering Manager).You will be embedded in a multi-disciplinary squad (Product, Mobile, Design, Data) alongside one Senior Backend Engineer, co-lead of the squad.Your role?Design, ship, and operate high-risk backend experiments that validate bold product bets, while keeping systems resilient, scalable, and cost-efficient within a fast iteration cycle.This is not a “maintenance” role.It’s about building, testing, rolling back, iterating and learning fast.Your responsibilitiesExperiments & Product BetsDesign and deliver backend capabilities from specs to production rollout/rollback.Define and instrument success metrics with cross-functional partners.Iterate quickly based on experiment results (KPIs, dashboards, quantitative signals).Architecture & OperabilityBuild resilient, scalable, and cost-efficient systems adapted to high-risk experimentation.Diagnose and fix complex production issues using logs, metrics, and observability tools.Anticipate operational impact (deployment, rollback, monitoring, cost).Standards & Knowledge SharingStrengthen team-level best practices and reusable patterns.Contribute to documentation, RFCs, and internal usability of squad-owned systems.Mentor peers through code reviews and pairing (mentorship is a plus, not mandatory).Our technical environment / Tools we useBackend: Node.js & TypeScriptArchitecture: Event-driven systems (Kafka, RabbitMQ, NATS)Databases: NoSQL, key-value stores, relational databasesObservability: Datadog, GrafanaPractices: RFC processes, technical specs, structured decision-makingWho you areYou have 5+ years of backend experience, ideally in startup/scale-up environments.You are proficient in Node.js and TypeScript.You have solid experience designing APIs (performance, security, observability).You have worked with event-driven systems (Kafka, RabbitMQ, NATS).You apply strong engineering best practices (testing, code quality, resilience).You have a product mindset and enjoy collaborating closely with Product.You communicate clearly and can explain complex technical topics to non-technical stakeholders.You are comfortable working in English in an international environment.Nice to have:Experience in scalable architecture design.Experience mentoring peers.Familiarity with RFC-style structured decision-making.In your first 6 months, you willShip at least one high-risk, country-scoped backend experiment end-to-end, including safe rollout/rollback and measurable success metricsEstablish lightweight, reusable experimentation patterns (instrumentation, dashboards, operability guardrails).Improve one systemic area revealed by experiments (reliability, performance, or internal usability) and drive measurable impactIncrease the squad’s ability to test bold ideas without compromising platform stability.The recruitment processPhone screen with a Talent Acquisition ManagerInterview with Armand (Engineering Manager)Technical test (home assignment + debrief & system design)Cultural Fit AssessmentsWhat we offerA highly competitive salary range as well as equity in the companyA highly flexible remote work policy, 2 days at the office per month, with monthly team events.We also cover fees for external professional events and meetups (Android Makers, etc…)Great health insurance coverage for both you and your family by Alan, fully paid for by Yubo !Numerous benefits for parents: additional parental leave, easy access to nurseries and daycare facilities in France.Our approach to privacy & safetyAs part of your role, you may handle tools and features involving personal data. We expect all employees to demonstrate strong awareness of privacy and safety issues, and to actively support our Privacy & Safety by Design efforts.Join Yubo and help shape the future of Social Discovery while enjoying a culture that values flexibility, well-being, and impact. Here’s how we live our mission every day:You own the impact: Step up, adapt, and make it matterUnconventionally Smart: Hack with intent, borrow smart, build betterBe Bold & Resilient: Raise your head, break barriers, keep moving forwardOne team, one mission: No egos, no passengers, just shared wins Trust & Flexibility: Our hybrid model calls for only two office days a month; the rest is up to the rhythm that works best for you. Enjoy Top-notch BenefitsCulture is central at Yubo, hence the numerous benefits:Cool Workplace: enjoy our amazing Parisian office and our many hybrid work optionsTeam Activities: participate in get-togethers, events, and team-building activitiesFamily-Friendly: we support parents with childcare options and family-friendly policiesWellness Programs: benefit from comprehensive health insu