Concepteur de produits principal/ Senior Product Designer

The Senior Product Designer owns the end-to-end user experience of Acumatica applications, shapes workflows, and aligns them with the product vision. As an active member of the discovery team, they collaborate with the Product Manager, Business Analyst, Engineering Lead, and backend developers to translate business requirements into validated, scalable solutions. This role includes building working prototypes for Business Analysts to specify from and for backend developers to connect services to, modeling system behavior, writing clear behavioral specifications for engineers and AI agents, and ensuring AI-generated output meets quality and accessibility standards. The Senior Product Designer also mentors team members, leads cross-functional design sprints, and links design work to measurable business outcomes.  MAJOR ROLES & RESPONSIBILITIES  Discovery & Validation: Understanding Users and Problems  • Conduct and synthesize user research and competitive analysis, including emerging UX patterns and AI capabilities, to inform design direction  • Validate early concepts with users through working prototypes before committing to full design or engineering effort  • Lead usability and UX acceptance testing to ensure the experience functions as designed. Define success metrics such as task completion, error rate, CSAT, and adoption with product managers. Identify and raise UX defects before release.   Interactive Systems Design: Designing Behavior, Not Just Screens  • Own end-to-end UX for assigned epics, including AI-surfaced and headless experiences. Partner with the Engineering Lead to assess feasibility and trade-offs.  • Model user flows, screen and component states, and transitions, defining how the UI responds to user input, validation, system events, and API responses  • Design for non-deterministic AI output by defining fallback, recovery, and human-in-the-loop behavior when results are incomplete, incorrect, or low confidence  Prototype & Behavioral Specification: Building the Working Reference  • Build working code prototypes in the component library to serve as reference artifacts. These prototypes help Business Analysts write functional and business specifications and enable backend developers to connect real services.  • Structure prototypes to be plug-in ready, with defined mock data structures and clear data shapes. Keep the UI separate from data logic to prevent backend rework.  • Write behavioral specifications that AI coding agents can interpret clearly, covering interaction rules, states, edge cases, and UI acceptance criteria.  • Define UI-level guardrails for AI-surfaced features, such as how uncertainty is displayed, when human confirmation is required, and how users can override. Partner with the Product Manager and Business Analyst to establish the supporting business rules.  • Annotate prototypes with known business rules and open questions to surface rules that do not appear on screen, such as permissions, validation logic, and calculations, early in the process.  • Build reusable specification templates, prompt templates, and context files to ensure AI-generated output remains consistent with the design system.  Design Systems & Versioning: Keeping Design and Code in Sync  • Work directly in BitBucket repositories: create branches, commit changes, open and review pull requests, and resolve basic merge conflicts  • Store and edit design tokens in the code repository, keeping Figma variables and coded tokens aligned  • Treat the coded component library as the source of truth, moving beyond Figma-only handoff. Structure the system so AI agents can use it reliably.  AI-Assisted Workflows & Design QA: Building Fast, Shipping Right  • Use AI tools (e.g., Cursor, Claude Code, Figma Make) to build