Senior Backend Engineer - TypeScript / Node.js / AWS - Nancy, France (on-site, Place Stanislas)[.]
Baliston·Nancy, France (on-site, Place Stanislas)·Full-time
Senior Backend Engineer
TypeScript / Node.js / AWS
About Baliston
At Baliston, we believe shoes can do more than cover your feet, they can help you understand your body. We build tech-augmented, 100% recyclable smart footwear that blends timeless design with health technology. An embedded sensor module analyzes how you move and, through our apps, delivers clinical-grade insights that help reduce fatigue, back pain, and injury risk, technology already trusted by over 1,000 healthcare practitioners worldwide.
Behind every step our users take, there's a cloud platform doing the heavy lifting, ingesting sensor data, processing it in real time, and serving it back through fast, reliable APIs. That platform is what you'll own.
Why this role matters
Our backend is the bridge between hardware in the real world and the insights our users rely on. You'll join a small, senior team where your architectural decisions ship to production and directly shape the experience of every Baliston wearer. You'll work from our office at Place Stanislas in the heart of Nancy, one of France's most beautiful squares, alongside the engineers building our products.
What's already in place:
- A production backend and cloud infrastructure built on AWS and Node.js/TypeScript
- Live applications powered by this backend: Baliston Health, Baliston Connect, and other apps supporting our technology
- A production SDK, maintained by a dedicated SDK team you'll collaborate with
What you’ll do
Backend & API architecture
- Develop, maintain, and optimize our core backends in Node.js and TypeScript
- Own the API contract between our cloud and client applications, REST, payload optimization, and security
- Ensure performance, resilience, and scalability across data pipelines and database interactions
Supporting our apps and devices
- Partner closely with mobile engineers to define clean API schemas and data contracts
- Build server-side features, background jobs, and cloud events that support complex device and hardware interactions
Technical leadership & platform quality
- Drive CI/CD automation, test strategy, logging, and cloud observability (monitoring, alerting)
- Reduce friction for everyone through clear documentation and API specifications
- Raise the bar through code reviews, system design decisions, and hands-on mentoring
What we’re looking for
Must-haves
- Location: You currently live within commuting distance of Nancy, France, or you’re genuinely willing and able to relocate to work on-site at our Place Stanislas office (see our location policy below, we’re serious about it)
- Deep production experience with Node.js and TypeScript backends
- Strong architecture skills: API design, modularization, testing strategies, database modeling, maintainability
- Practical AWS experience, especially Lambda, plus API Gateway, CloudWatch, DynamoDB/S3, IAM
- A track record of building and running production APIs for mobile or client-facing applications
Nice-to-haves
- Security: Hands-on experience with secure software design, identity management (OAuth2, OIDC, JWT), vulnerability management, and hardening cloud/API infrastructure
- Multi-database ecosystems: Practical experience across document, key-value, and relational paradigms (MongoDB, DynamoDB, PostgreSQL, Redis)
- Compliance: Familiarity with ISO/IEC 27001, GDPR, and technical audit workflows
Location & relocation policy, please read carefully
We’re a hardware-meets-software team, and being in the same room matters to how we build.
On-site presence at our Nancy office is mandatory. To apply, you must either already live near Nancy or be genuinely willing and able to relocate to Nancy, France.
We say this with respect for your time and ours:please do not apply if you cannot meet this requirement.
Applications submitted without meeting the location requirement, or without any genuine intention or ability to work on-site in Nancy, will result in the profile being permanently excluded from all current and future opportunities across our organization. We’d much rather you skip this one and apply to a future role that truly fits.
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