Licorne Society a été missionné par une startup en pleine croissance pour les aider à trouver leur Lead Backend Engineer.

Location: EU-based preferred

Work Mode: Remote-First, you will have maximum 10 days of travel per quarter to meetup with the team in France or another EU country. You can also choose to work from our Paris office.

We’re looking for a Lead Backend Engineer to own the design and implementation of our backend infrastructure as we scale from 1 to 10M+ daily active users.

Today, our backend is built on Firebase by our mobile engineers. As we grow, we need someone who can own the backend strategy, guide our evolution beyond Firebase when necessary, and build a robust, secure, reliable, and cost-efficient platform for the future.

This role is perfect for someone who combines strong technical expertise with architectural thinking, is comfortable making foundational decisions, and wants to shape both the technical stack and the engineering practices & culture around it.

What You’ll Do

• Lead backend architecture: Own the design and evolution of our backend infrastructure, balancing Firebase today with next-generation stack plans.

• Build scalable APIs: Create efficient, well-structured, backward-compatible APIs optimized for mobile clients.

• Design data models: Build scalable schemas to support rapid product iterations and growth to 10M+ DAUs.

• Ensure operational excellence: Define SLOs/SLIs, implement monitoring, logging, tracing, alerting, and lead incident response and root-cause analysis.

• Drive security & compliance: Ensure authentication, encryption, and GDPR (and similar regulations) compliance from day one.

• Document & evangelize: Maintain backend architecture documentation and workflows, enabling smooth onboarding and collaboration.

• Collaborate cross-functionally: Partner with mobile and product teams, clearly explaining trade-offs and inviting constructive debate.

• Balance simplicity and scale: Build what’s needed today while planning for future growth.

• Maintain CI/CD & IaC: Improve pipelines and Infrastructure as Code practices.

• Contribute to AI & notification features: Support AI-powered and silent push notification flows that enhance mobile experiences.

• Proven experience designing and scaling backend infrastructure for millions of users.

• Hands-on experience building cost-efficient, secure, and reliable systems.

Technical Skills

• Strong JavaScript/TypeScript expertise.

• Experience building and scaling backend infrastructure for large-scale consumer or mobile-first products.

• Hands-on with cloud platforms (preferably GCP) and building scalable services.

• Experience with Firebase (Auth, Firestore, Cloud Functions) is a plus.

• Proficiency in SQL & NoSQL databases and designing scalable data models.

• Experience with CI/CD pipelines & IaC.

• Knowledge of API versioning and backward-compatibility strategies.

• Familiarity with security, privacy, and compliance best practices.

Mindset

• Product-oriented & pragmatic: Focused on delivering user value over over-engineering.

• Strong communicator: Explains trade-offs clearly and invites healthy debate.

• Startup-ready: Adaptable, iterative, and unafraid to rethink what no longer works.

• Data-savvy: Experienced in structuring and managing data at scale.

• Understands mobile client needs and builds APIs that serve them efficiently.

• Reliability-driven: Deep care for operational excellence and measurable performance.

Nice-to-have

• ETL processes, modern data stack tools (Dagster, dbt, Snowflake).

• Experience with AI integrations and silent push notifications.