own the architecture, raise the technical bar, and keep a system that handles business-critical call traffic reliable and fast.
work mainly on our core telephony service — an async FastAPI application following Domain-Driven Design, progressively migrating a legacy codebase toward a clean, well-specified architecture.
own the architecture and technical direction of the telephony backend, and drive the ongoing migration from legacy code to our DDD architecture.
design and build reliable, event-driven services: call tracking, scheduling, external event consumption, and provider integrations (telephony providers, Salesforce Pub/Sub).
write robust async Python (FastAPI, SQLAlchemy) with strong typing, full test coverage, and clear specifications.
make and document the hard technical calls — data modeling, throttling, retries, failure handling — pragmatically weighing trade-offs on a system where downtime means lost calls.
leverage AI tooling (Claude Code, Cursor, AI agents) to ship faster and better, and define how the team adopts AI responsibly and within our usage and security guidelines.
set the engineering standard: code reviews, mentoring, and lifting the team’s practices around testing, observability, and CI/CD.
collaborate closely with Product, Ops and other engineering teams to turn business needs into solid technical solutions.
own your work end-to-end — from design through autonomous deployment and monitoring in production.

8+ years of backend software engineering, with deep expertise in Python.
Telephony, real-time systems or CTI integration experience is a plus.
Strong with our stack or close equivalents: FastAPI (or Django/Flask), async SQLAlchemy / PostgreSQL, Redis, message queues, AWS.
An AI-powered engineer — you use AI coding assistants and agents fluently as part of your daily workflow, and you know how to apply them responsibly and in compliance with usage, security and data-handling rules. This is a top priority for us.
Proven track record designing and operating business-critical production backend services at scale — async, event-driven, integration-heavy systems where reliability is non-negotiable.
Pragmatic by nature: you make sound, trade-off-driven decisions, ship the right thing rather than the perfect thing, and know when to optimize and when to keep it simple.
Solid grasp of software architecture (DDD a strong plus), clean code, and rigorous testing — you treat tests, types and specs as part of the job, not an afterthought.
Experience mentoring engineers and raising team standards.
Fluent in English, working French is a plus.

Grow in an international and inclusive environment : Everyone has their place at papernest!
Compensation : You’ll receive a Business Creator Share Warrants (BSPCE) package upon joining, according to the company’s current policy.
Perks : As a home insurance provider and supplier of green electricity and gas, we offer great deals to our employees—because our perks shouldn't be reserved just for our customers!
Health : We offer Alan, a hassle-free and paperless health insurance provider, with 50% coverage by papernest.
Meals : Enjoy a Swile card for your €9/day meal vouchers, 50% funded by papernest. Plus, there’s breakfast every Tuesday at the office, an Ideal Garden fridge on site, and discounts at partner restaurants for healthy and balanced meals.
Sport : access to GYMLIB service to enjoy discounted gym membership.
Training : Your development matters. You’ll have access to continuous training tailored to your goals—whether they’re technical, linguistic, or managerial.
Career growth : Multiple paths are open to you to grow—by deepening your expertise or exploring new directions. We're here to support your professional ambitions.
Remote work : Benefit from 2 days of remote work per week to boost your focus and productivity.
Legal advice : Enjoy privileged access to Ekie for personalized legal and tax advice, helping you handle all your administrative needs with peace of mind!

Senior Backend Developer, Python

Key skills