Senior Fullstack Developer – AI SaaS Builder

42Lab.co

Développeur fullstack senior construisant des SaaS IA rentables pour des entrepreneurs ambitieux chez 42Lab.co. Développant rapidement des produits complets, agents IA et fonctionnalités générant de la traction business.

Posted 8/17/2026full-timeValbonne • 🇫🇷 FranceSeniorWebsite

Core Competencies

Role fit

Core Competencies

Use this summary to align your resume positioning with the role.

Demonstrates expertise in Fullstack Development, particularly with Next.js, React, and TypeScript, while effectively integrating AI APIs to enhance SaaS product functionality. Proven ability to manage multiple projects and communicate technical concepts to non-technical stakeholders.

Highest-signal resume keywords

Fullstack DevelopmentNext.jsReactTypeScriptPostgreSQL

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

Fullstack DevelopmentNext.jsReactTypeScriptPostgreSQLServerless ArchitecturesAI API IntegrationProduction-Ready ProductsTechnical Solution DevelopmentSaaS Product Development

Soft Skills

AutonomyCommunicationCollaborationProblem-SolvingAdaptability

Tools & Technologies

OpenAIClaudeInngestBetter AuthDrizzle ORM

Industry Keywords

SaaSAIWorkflow AutomationTechnical Decision MakingProduct Shipping Processes

Tech Stack

Tools & technologies

JavaScriptNext.jsPostgresReactTypeScript

About the role

Key responsibilities & impact

Develop end-to-end SaaS products from A to Z in fast sprints
Implement intelligent AI agents to automate complex workflows
Work directly with founders to translate their vision into features that drive traction
Maintain the in-house boilerplate and continuously improve shipping processes
Manage two projects in parallel without sacrificing quality
Contribute to strategic technical decisions that influence SaaS success
Turn entrepreneurs' visions into high-performing SaaS products

Requirements

What you’ll need

3+ years of fullstack development experience with production products
Proficiency in Next.js, React and TypeScript
Strong experience with PostgreSQL and serverless architectures
Ability to integrate AI APIs, including OpenAI, Claude, embeddings, structured outputs, RAG, model-agnostic approaches and memory systems
Autonomy to turn a business need into a technical solution
Strong focus on shipping and building production-ready products
Ability to explain technical topics to non-technical stakeholders
Candidates missing one or two items may still proceed if they are ready to learn quickly
Experience with Inngest, Better Auth and Drizzle ORM — bonus
Having built SaaS from scratch — bonus
Understanding of AI's business value — bonus
Passion for learning and technological and AI advances — bonus
Resume and links to your best projects required when applying

Benefits

Comp & perks

Competitive compensation package
Bonuses tied to the success of the SaaS products you build
Modern stack, latest technologies and complete technical freedom
No unnecessary meetings or corporate processes
Work with A-players
Opportunity to progress to a Lead Dev role
Mentorship and knowledge sharing to ramp up quickly