AI Engineer

Mendo

. Train, fine-tune, and evaluate proprietary language models, including small models running on-device .

Posted 9/15/2026full-timeParis • FranceMid-LevelSenior💰 €56,000 - €65,000 per yearWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in ML/AI engineering with a focus on fine-tuning language models, optimizing production AI systems, and mentoring junior engineers. Proficient in Python and TypeScript, with a strong understanding of evaluation-driven development and production deployment.

Highest-signal resume keywords

ML/AI Engineering ExperienceLLM Fine-TuningProduction AI System OptimizationPython ProficiencyBilingual in French and English

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Hard Skills

LLM Fine-TuningRAGEmbeddingsRegression TestingProduction AI Systems MonitoringSoftware Engineering FundamentalsTestingCIObservabilityOn-Device Model Deployment

Soft Skills

Execution-FocusedPragmaticAutonomousCuriosityTeam Spirit

Industry Keywords

Language ModelsDatasetsEvaluation HarnessesAI FeaturesCost OptimizationLatencyQualityAI Trade-OffsDocumentationMentoring

Tech Stack

Tools & technologies

PythonTypeScript

About the role

Key responsibilities & impact

Train, fine-tune, and evaluate proprietary language models, including small models running on-device
Curate and maintain datasets, golden sets, and evaluation harnesses
Ship model updates to production and measure their impact
Own the health of production AI features across quality, cost, and latency
Detect silent regressions and debug AI incidents end to end
Maintain models, prompts, and pipelines as tooling and APIs evolve
Partner with product managers and engineers on new AI use cases
Build rapid, evidence-based prototypes and provide evaluation, cost, and latency data
Explain AI trade-offs to non-technical colleagues
Document work and mentor junior engineers and interns on AI topics
Work alongside the CTO and engineering squads, owning the AI workstream for a product area

Requirements

What you’ll need

3–5 years of experience in ML/AI engineering, with models or AI features shipped and operated in production
Hands-on experience with LLM fine-tuning, RAG, embeddings, and evaluation methods, including golden sets, LLM-as-a-judge, and regression testing
Experience monitoring and optimizing production AI systems for cost, latency, and quality
Strong software engineering fundamentals, including testing, CI, and observability
Proficiency in Python and the ability to work across a TypeScript product codebase
Experience with small language models (SLMs) and on-device/on-premises model deployment is a strong plus
Execution-focused, pragmatic, product-minded, and autonomous
Naturally rigorous, with a strong instinct for evaluation-driven development
Genuine curiosity about the fast-moving AI landscape
Strong team spirit and a clear sense of priorities in a fast-moving scale-up
Alignment with Mendo's values: Learning, Innovation, Excellence, Kindness, and Transparency
Excellent command of French and English, both technically and professionally

Benefits

Comp & perks

BSPCE (equity) under our Series A policy
Hybrid model with two days in the office and three days remote
A learning environment with a team passionate about new technologies and generative AI
A stimulating workplace with a young and supportive culture
A meaningful mission: helping make AI accessible and impactful for everyone