Full-stack Engineer (AI)

Evaneos; Paris; Hybride; EUR 67 000 - 75 000; Plein temps

Avantages offerts par ce poste

La Voyagerie HQ in Paris

Up to 3 days remote per week in Paris

Remote days on-site per month

Travel budget with Evaneos trips

Wellpass (yoga, meditation, sports)

Résumé du poste

Evaneos, a Paris-based travel marketplace, is hiring an AI Product Engineer to build AI-native travel experiences used by real travelers in production. You will design, build, and operate AI products powered by agentic architectures, from problem framing to live monitoring, focusing on traveler-facing AI products that improve conversion, experience, and cost.

Join Pathfinder in Evaneos Innovation, a small, focused team in Paris with hybrid work options.

Qualifications

• Built and deployed AI agents in production with real users.
• Designed and implemented LLM evaluation pipelines (offline benchmarks and online metrics).
• Implemented observability for LLM systems (tracing/monitoring for AI products).
• Owned end-to-end AI product delivery from framing to live monitoring.

Responsabilités

• Design agent architectures: runtime, tool systems, orchestration patterns, middleware, state management.
• Own context engineering to steer models and control costs.
• Build evaluation pipelines and observability to detect hallucinations, drift, and regressions.
• Balance quality, speed, and cost once something is live.
• Debug production issues and manage model migrations and tool call errors.
• Own the infra and deployment pipeline, ensure fast dev environments.
• Collaborate with product, design and business to solve end-to-end problems.

Connaissances

AI agents in production

Full stack development

LLM observability

LLM evaluation pipelines

APIs and data stores

Outils

Langfuse

Langsmith

Claude Agent SDK

Langchain DeepAgents

Docker

Description du poste

Role & impact

At Evaneos, our mission is simple: to help travelers experience trips that are more local, more responsible, and more human, all around the world.

Within the Innovation Department, the Pathfinder team is reinventing how travelers design their tailor‑made trips, with AI as the central lever of the experience.

We are hiring an AI Product Engineer to ship AI‑native travel experiences used by real travelers in production. You’ll design, build, and operate AI products powered by agentic architectures, working end‑to‑end from problem framing to live monitoring, always in service of real user and business needs.

Your impact: you’ll build traveler‑facing AI products that move metrics on conversion, experience, and cost. Two are already live and serving traffic: an AI trip designer that helps travelers explore and customize itineraries and a conversational experience that turns their intent into a structured travel project local agencies can act on. Real products, not internal tools.

The innovation Department

Within the Innovation Department, AI runs on two complementary fronts:

• Pathfinder: we design and build AI‑native products to unlock new growth opportunities and keep Evaneos at the forefront of its market.
• AI Company: we solve real team problems to improve internal efficiency, accelerate execution, and build a practical AI‑native culture.

You’ll join Pathfinder.

It’s a small, focused team:

• Clément Stouls (Product Manager),
• Lou Anfriani (Product Designer),
• Jocelyne Boun (AI Product Engineer) & Timothé Hofmann (Full stack Engineer),
• You (Full stack Engineer).

The team reports to Romain Quilliot (Head of Innovation), who leads strategy, operations, and execution. By design, the team member owns it’s direction and proposes initiatives — with direct exposure to C‑level leadership on product and business strategy.

Our stack, at a glance:

Languages: Python, TypeScript

AI/LLM: LiteLLM Gateway, Langfuse, Langsmith, multi‑provider (Anthropic, OpenAI, Gemini, Mistral), Langchain DeepAgents, Claude Agent SDK

Frontend: CopilotKit, React

Infra: Docker, Kubernetes, CI/CD (GitHub Actions)

Data: PostgreSQL, MongoDB, vector databases

Dev workflow: Claude Code, Cursor, Codex, In house tooling

Your role as Fullstack Engineer (AI)

Build AI‑native products (AI agents)

• Design agent architectures: runtime, tool systems, orchestration patterns, middleware, state management, RAG. Choose the right pattern for the right problem!
• Own context engineering: shape what the models see and find ways to better steer the model and system, raising quality while controlling cost.
• Make quality measurable: build evaluation pipelines (offline benchmarks plus online metrics) and observability to catch hallucinations, drift, and regressions before users do.
• Own the economic viability: once something is live, find the right balance of quality, speed, and cost.
• Keep it running: debug production issues on non‑deterministic systems, handle model migrations when providers change their APIs, and deal with structured output failures and tool call errors.
• Own the infra: You build it, you ship it. Keep the dev environment fast and the deployment pipeline reliable.
• Own problems end‑to‑end: from framing to resolution, in collaboration with product, design, and business stakeholders.

Be a bridge between tech and product

• Take an active part in product direction, grounded in real user and business stakes.
• Translate technical constraints into product options, and explain the paradigm shifts AI brings.
• Proactively communicate on progress, decisions, and blockers: position yourself as an enabler for the team.

Grow our internal AI community

• Co‑lead the AI Champions Tech program, leveling up Product & Tech across Evaneos on AI practices and knowledge.
• Share your learnings with the Innovation team and wider tech community.
• Run workshops and talks that demystify what matters in the agentic era.

Why join us?

You build the product, not the platform. Focus on shipping AI experiences directly to travelers: real users, real conversion, real business impact.

Full ownership in a team that fits in one room. No ticket queues, no handoffs between ML and product teams. You frame problems with the PM, design solutions with the designer, build and ship them yourself, then watch the traces to know if it works. The loop is tight and you own all of it.

AI at the core of a 15‑year‑old profitable marketplace. This isn’t a startup burning cash on an AI bet. It’s an established travel company with real revenue, real users across 160+ destinations in over 5 markets, and a strategic conviction that AI will reshape its core experience. Startup autonomy with business‑model gravity.

What’s in it for you?

• La Voyagerie: our lively HQ in the 9th arrondissement of Paris
• Based in Paris? Up to 3 days of remote work per week.
• Fully remote? Up to 2 consecutive days on‑site per month when the whole team comes together in Paris.
• Travel budget through the CSE to experience Evaneos trips.
• Remote work from abroad several times a year.
• 25 paid leave days + 14 RTT days.
• Choice of PC or MacBook Pro.
• Wellpass (yoga, meditation, sports partially covered).
• Cultural lunches, seminars, afterworks, and regular team moments.

Salary: €67–75K gross annual, based on experience.

What we’re looking for

Technical skills

• You have at least 5 years of software development experience and are comfortable with APIs and data stores.
• You’ve built and deployed AI agents in production with real users: not just PoCs or hackathon projects.
• You’ve set up or contributed to LLM evaluation pipelines (offline benchmarks and/or online metrics) and have designed guardrails.
• You have hands‑on experience with observability for LLM systems: tracing, monitoring, diagnosing regressions from traces (Langfuse, LangSmith, or equivalent).

Mindset & ways of working

• Curious and passionate about AI: you keep up with the state of the art, test things to understand them, and apply what you learn to what you build.
• Full‑stack at heart: in a small team, you’re happy to touch front, back, and infra. No “That’s not my job.”
• Strong ownership: you spot problems, propose solutions, and move forward while keeping everyone in the loop. You finish what you start.
• Product appetite: you want to understand users, conversion, and the business. Engineering is a means to an end: crafting meaningful experiences and solving real customer problems.
• Team player: You like pairing, sharing knowledge, communicating clearly, and pulling in the same direction.
• Fluent in professional English.

You’ll thrive here if

• You want to build and ship AI products to real users, not do pure ML research.
• You care about the product outcome, not just the technical pipeline.
• You’re comfortable working daily alongside product, design, and business stakeholders.