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# Lead Software Engineer (M/F) - CDI - Paris

- **Company:** Wiremind
- **Location:** Paris, France (Remote available)
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Clean Code Principles, Software as a Service, Code Review, Continuous Delivery, D3.Js, Elasticsearch, Python (Programming Language), PostgreSQL, Redis, Prometheus, Next.js, Software Engineering, SQLAlchemy, TypeScript, Grafana, Technical Debt, Backend, Gitlab, AngularJS, Kubernetes, Front End Software Development, Kibana, Software Coding
- **Published:** September 28, 2026
- **Apply:** https://www.indeed.com/viewjob?jk=723875eab2aeea05

## About the Role

* You have 5+ years of experience as a Software Engineer working with Python or a similar backend language on a large codebase with many contributors, and have already mentored or managed a small team of software engineers
 * You are a builder: you love writing code, solving hard technical problems, and raising the quality bar through your own output.
 * Strong fullstack background with a backend-first mindset (Python), fully comfortable owning frontend work (Next.js or equivalent).
 * Good communication skills, able to collaborate with Product and align technical decisions with business priorities - without spending most of your time in meetings.
 * Bonus: Experience in SaaS, event-tech, or working on complex interfaces and operations-heavy B2B2C products.
 * You have a native or fluent level in French

## Description

We are looking for a Lead Software Engineer to take the technical lead of this squad. Reporting to the Head of Software Engineering of Cayzn, you will work closely with the Product Owner, Product Experts, Data Scientists and the Platform team to ship reliable and scalable features for our international clients (railways, airlines, bus operators).

Technical ownership & architecture

 * Own the architecture of the business rules engine: rule language, parsing, evaluation and performance at scale
 * Design and develop efficient code that is easy to maintain, mainly on the backend and on the frontend when needed
 * Own the technical decisions of the squad: refactoring, scalability, trade-offs between new features and technical debt
 * Improve operational quality: monitoring, alerting, performance and incident follow-up

Delivery & product

 * Understand in depth how revenue managers work, to make the right implementation choices
 * Work with the Product Owner to find the most efficient path to delivery and plan work consistently
 * Take part in roadmap decisions to keep a good balance between refactoring, scaling work and new features

Team & knowledge sharing

 * Review code, mentor the developers of the squad and help them grow
 * Share your knowledge, and bring in new practices, frameworks or tools where they add value
 * Stay hands-on: around 70% of your time on development, on the most challenging parts of the codebase

Technical stack:

 * Backend: Python 3.15 , SQLAlchemy, Remoulade (in-house task queue)
 * Frontend: Angular, TypeScript, D3.js
 * Data-store: Postgresql, Elasticsearch, Redis
 * Gitlab for continuous delivery
 * Kubernetes for infrastructure
 * Prometheus/Grafana and Kibana for operations, * A screening interview with Anne-Laure our Lead Talent Acquisition Manager
 * An interview with Antoine, the Head of Software Engineering of Cayzn
 * A technical test or case study to prepare
 * A technical interview at our offices to go through your test and meet the Cayzn team
 * A final interview with Charles ou CTO and co-founder