Design an architecture
For a new product or a rebuild: breakdown into modules and services, reasoned technical choices, proof of concept (POC) for the risky parts.
- Architecture document and diagrams
- Documented and compared decisions
- POC and estimate
Architecture · Python · C++ · AI
Python software architect in Lyon
Sébastien Mizrahi is a senior software architect and freelance Python / C++ expert in Lyon (Chaponost). He designs the architecture of software that has to last: Python platforms, AI integration, critical software. A software professional since 2006, he works on site in Lyon or remotely.
What a software architect does
A software architect decides the structure of a system before and during its development: how to split it up, which technologies to choose, how the components communicate, how the software will be tested, deployed and maintained. He makes these choices explicit, reasoned and documented, so the team can rely on them.
Where a developer writes a feature, the architect makes sure the whole stays consistent, secure, fast and maintainable, including when the team changes or the product grows.
Why it matters even more in the age of AI
AI assistants produce code very quickly, but they do not design a consistent architecture and they do not take responsibility for the choices. The faster code is written, the more you need someone to set the framework, review, validate and guarantee security, performance and compliance with business or regulatory constraints. I use AI myself every day (see my article): it speeds up execution, architecture remains expert work.
Services
My work as a software architect
Every engagement ends with deliverables your team can take over without me.
Audit what exists
Before taking over, extending or rebuilding an application: a review of the code and architecture, risks and priorities.
- Prioritised audit report
- Map of risks and technical debt
- Recovery plan
Integrate AI
Assistants, RAG, agents and automations connected to your tools, while keeping control of your data and costs.
- Model routing (LiteLLM)
- Local RAG and actions (MCP, n8n)
- Privacy-friendly architecture
Secure critical software
For software subject to safety or performance requirements, in C++ as well as Python.
- MISRA rules, IEC 62304 standard
- Code reviews and automated tests
- Traceability and documentation
Support the team
Code reviews, technical leadership and knowledge transfer, as team leader at V3D and at Keranova.
- Architecture and code reviews
- Upskilling the team
- Documented handover
Industrialise deployment
Containers, orchestration and asynchronous tasks for services that scale.
- Docker and Kubernetes
- Celery and task queues
- Continuous integration and deployment
Redesign of SOGo, an open source groupware
Architecture proposal, technical studies and a POC of a MAPI server, then development of the calendar, the contacts and an asynchronous agent: a Python/Flask API on Kubernetes, with tasks handed to Celery.
Python · Flask · Kubernetes · Celery · Docker Read the case study →Multi-client AI chatbot platform
Architecture and development: LLM routing through LiteLLM, local RAG, actions (Python/HTTP hooks, MCP, n8n), web, Telegram, WhatsApp and local voice, with privacy as a design principle.
Python · FastAPI · LiteLLM · RAG · MCPLaser cataract surgery robot
Calibration software, embedded development, OCT and phaco integration for a medical device; organisation of the software team and code reviews.
C++ · Python · MISRA · IEC 62304 Method
How an engagement runs
Understand
Needs, business and regulatory constraints, current state of the existing system.
Design
Architecture, reasoned technical choices, estimate.
Build
Development, code reviews, automated tests.
Hand over
Detailed technical documentation, handover, maintenance.
Technologies
Python (FastAPI, Flask, Celery, pytest), C++ and C (MISRA), AI (LiteLLM, RAG, MCP, n8n, TensorFlow, Keras), cloud and DevOps (Docker, Kubernetes, CI/CD, Linux), web and mobile (Node.js, PHP, Swift, Objective-C). The choice always depends on your context: what already exists, the team that will maintain the software and the constraints of your business.
Software architect in Lyon and remote
Based in Chaponost, in the Lyon metropolitan area, I work on site in Lyon and the Auvergne-Rhône-Alpes region when the project calls for it, and remotely for companies anywhere in France or abroad. Agencies, IT services companies, startups, SMEs and large corporations: I have worked for Keranova, SoftAtHome, Alinto, Chanel, Nestlé, Groupama, Sanofi Pasteur and NXP Semiconductors.
For Python projects, you can also read my technical articles on developpeur-python.com (in French).
Frequently asked questions
Your questions, my answers
What is a software architect?
The person who defines the structure of a piece of software: how it is split into modules and services, which technologies are used, how components communicate, and the testing and deployment strategy. They document these decisions and make sure the system stays coherent, secure, fast and maintainable over time.
What is the difference between a software architect and a developer?
The developer builds features; the architect designs the framework they fit into and checks that the whole stays coherent. Sébastien Mizrahi does both: he designs the architecture and develops the key parts, in Python as well as in C++.
Do you still need a software architect with AI assistants?
Yes, even more so: AI writes code fast, but it does not design a coherent architecture and it does not take responsibility for the choices. Someone has to define the framework, review and validate what is produced, and guarantee security, performance and compliance.
What kinds of projects do you work on?
Python platforms and backends (the redesign of SOGo 6 for Alinto on Kubernetes and Celery), AI platforms (Alfred: LiteLLM, RAG, MCP), critical software in C++ and Python (a laser surgery robot at Keranova, IEC 62304 standard), code audits and application takeovers. See the projects.
Do you only work in Lyon?
I am based in Chaponost, in the Lyon metropolitan area. I work on site in Lyon and in Auvergne-Rhône-Alpes when it helps, and remotely for companies anywhere in France or abroad.
How much does a freelance software architect cost?
My indicative rate is €68 per hour. For a well-defined assignment (architecture design, audit, prototype), I draw up a fixed-price quote after a first analysis of your needs, so that the cost is known before we start.
Can your services count towards the Innovation Tax Credit?
Le Programmeur is an approved provider for the Innovation Tax Credit (Crédit d'Impôt Innovation, CII): the innovation expenses entrusted to it can be included in the calculation of the tax credit, subject to the eligibility conditions in force. Find out more (in French).
Let's get in touch
A demanding project? Let's talk architecture.
From Chaponost, near Lyon, on site or remotely. A quick reply with a first analysis of your needs.