Lead Backend Engineer

About

Location: EU‑based preferred
Work Mode: Remote‑First (maximum 10 days of travel per quarter to meet the team in France or another EU country). Option to work from the Paris office.

Why Join l'entreprise?

• Mission‑Driven Impact: Help 1 Bn people reclaim their time and focus; the community has already saved 150 M+ hours.
• Shape the foundation: Define the backend architecture, infrastructure, and operations as the product scales to millions of users.
• Collaborative Culture: Small, high‑impact team that gathers quarterly for meetups and learning; nearly $1 M in revenue per employee.
• Meaningful challenges: Balance simplicity, security, cost, and scale for a product used by hundreds of thousands.
• Well‑Supported: Backed by world‑class investors and founders of companies like Pinterest, Snapchat, and Revolut.

Responsibilities

• Lead backend architecture: Own design and evolution of the 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 10 M+ daily active users.
• 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.

Requirements

Technical Skills

• Proven experience designing and scaling backend infrastructure for millions of users.
• Hands‑on experience building cost‑efficient, secure, and reliable systems.
• 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.