Senior Backend Software Engineer

CONTEXT Two video surveillance products are entering development at Vizzia: video-based traffic enforcement, with a first deployment in the UK, and ANPR, automatic number plate recognition run on legal request. Both rely on the same technical chain: camera-equipped units in the field, an edge to cloud pipeline, and a SaaS that officers use every day. That chain has to be built. Vizzia equips more than 250 local authorities for waste management today. Safety is the company's second product line, and it comes with its own constraints: data hosted in France on SecNumCloud infrastructure, evidential integrity, end to end traceability. The team is small and senior. You will join Jérémy Fornarino, Tech Lead, as the second backend engineer on Safety. Your mission: take ownership of a significant share of the backend for both products, across the full edge and cloud spectrum, and raise the team's quality bar alongside him. WHAT YOU'LL DO 1. The edge backend - Build and operate the services running on the field units: camera communication (VAPIX, ISAPI, ONVIF), NX Witness integration, local SQLite storage. - Optimise CPU and RAM on units with limited resources, and minimise the 4G/5G bandwidth of the video chain without degrading the user experience. - Debug a unit in production: SSH, logs, incident triage across the fleet. 2. The cloud backend - Design and operate the Hono APIs, the event-driven workers on the LavinMQ bus, and the Postgres/Drizzle data layer. - Drive the fleet from the cloud, orchestrate processing, and guarantee resynchronisation after a network outage with no data loss. - Deploy and operate: GitHub Actions, Helm, GKE, Datadog monitoring and alerting. 3. Ship enforcement and ANPR to production - Co-own both projects from technical spec through to production, working with the PM and the legal constraints of the domain: evidential integrity, audit trail, retention and purge, GDPR. - Architect the shared ingestion and edge to cloud layer that both products converge on. - Be one of the two backend leads on production incidents, able to handle an edge or cloud incident on your own. 4. Architecture and quality - Write your own ADRs, challenge Jérémy's, and be challenged in return. - Ship every module tested, harden the critical parts of the existing code (workers, pipelines), and let CI catch regressions rather than customers. - Keep to the monorepo conventions: moon, bun, ten bounded contexts. Current stack: TypeScript end to end, bun, Hono, Drizzle, Postgres on the cloud side, SQLite on the edge, LavinMQ bus, moon monorepo, GKE, Datadog. Infrastructure and DevOps experience is welcome but not a prerequisite, you can pick it up here. WHO YOU ARE - 4 to 8 years of backend experience, a significant part of it in SaaS. - TypeScript/Node in production, operational from day one. The rest of the stack is quick to learn on a solid foundation. - You have built and operated event-driven distributed systems in production: message buses, workers, idempotency, retries, with the structured logging, monitoring and incidents that come with them. - An engineering degree or a master's. - French and English full working proficiency - Curiosity about systems, networks and protocols. An unusual camera protocol or a unit stuck in a crashloop is the fun part of the job for you, not the scary one. - AI coding tools are part of how you work, and the quality holds up. Two bonus profiles, not prerequisites: video and streaming experience (codecs, containers, VMS), or a background in IoT, embedded or robotics. Domain knowledge can make up for a shorter SaaS track record. At Vizzia we work in a small team, with a lot of ownership and few silos. We are looking for someone who picks up topics without waiting, argues their choices, and genuinely cares about the problems the public sector is trying to solve. HIRING PROCESS 1. Screening with Talent Acquisition - 30' 2. Hiring Manager Interview - 1h 3. Backend technical test - 1h 4. [HQ/on-site] Team meeting & Final fit with VP Engineering - 2h 5. Referrals 6. Offer COMPENSATION & BENEFITS 💶 65–75K€ fixed + bonus 🏡 Hybrid work 🏝 Contrat cadre and RTT (between 8 and 12 days per year depending on public holidays) 💻 Work Macbook 💸 BSPCE 🍜 60% coverage of meal vouchers worth €9 per worked day 🚃/🚲 Sustainable mobility allowance 🏥 Mutuelle (Alan) 💼 Offices located in central Paris (9th arrondissement) ☀️ Annual offsite with the whole team and plenty of company events If you've read this far, you're probably very interested in the role and/or Vizzia. We'd like to hear from you even if you feel you don't check every box.