Senior Frontend Engineer

Mobi.AI • Somerville, MA

2d • Hybrid

About The Position

As a Senior Frontend Engineer at Mobi, you’ll own customer-facing features from defining the problem and making design trade-offs through implementation, release, and production support. You’ll turn ambiguous customer needs into reliable, accessible experiences for AI-powered travel, building interactive search and recommendation experiences, virtual concierge services, data-rich dashboards, and tool-driven interfaces for AI assistants and app integrations, including MCP apps. The work includes streaming and partial results, authentication and session continuity, and clear loading, error, and confirmation states.

You’ll work directly with clients, designers, backend engineers, and AI engineers to scope solutions, explain trade-offs, and iterate on what users need. AI-assisted software development is essential: you’ll use coding assistants and agents to implement, test, debug, and refine changes across an existing codebase, while remaining accountable for understanding the code and independently verifying correctness, security, accessibility, and maintainability.

Mobi partners with leading travel brands to build AI experiences that help people discover and book travel. The company combines AI expertise with travel-commerce experience, integrating with brands’ existing systems and building infrastructure for the next generation of travel commerce. Mobi values inclusion, resilience, transparency, collaboration, compassion, thoughtful design, and real-world impact.

Requirements

• Bachelor’s degree in Computer Science, Engineering, or a related field, or equivalent practical experience.
• Proficiency in HTML5, CSS3, and JavaScript (ES6+).
• Deep practical experience with React, including component architecture, state management, and diagnosing rendering and performance issues.
• Strong practical TypeScript skills, including type-safe component and API contracts and confidence working in an existing codebase.
• Experience writing and maintaining reliable automated frontend tests with tools such as Playwright, Jest, or Cypress, including asynchronous behavior and failure cases.
• Demonstrated proficiency with AI coding assistants and agents through professional or substantive project work that can be explained, tested, and critically reviewed.
• Experience directing AI tools through changes across multiple files in an existing codebase, including implementation, test generation, debugging, and refactoring.
• Strong judgment in evaluating AI-generated solutions: ability to explain code, verify behavior, identify errors, and recognize when independent investigation or another approach is needed.
• Experience integrating frontend applications with RESTful APIs and asynchronous services, including authentication, session state, and error recovery.
• Understanding of responsive design principles and cross-browser compatibility.
• Experience with build tools and version control, such as Next, Vite, and Git.
• Evidence of independently shipping and supporting complex frontend features, explaining design trade-offs, and collaborating effectively with designers, customers, and engineers.

Nice To Haves

• Experience shipping AI-powered user interfaces.
• Understanding of Model Context Protocol (MCP) and response streaming.

Responsibilities

• Design, build, and maintain production React and TypeScript applications, making explicit trade-offs in component architecture, state management, and maintainability.
• Turn designs and prototypes into responsive, accessible interfaces, including keyboard navigation, screen reader support, and usable pending, error, and confirmation states.
• Use AI coding assistants and agents throughout the development lifecycle to accelerate delivery while maintaining standards for correctness, accessibility, performance, and maintainability.
• Work with design, backend, and AI engineers to define UI contracts for tool calls, streaming, session state, and recoverable failures.
• Measure and improve frontend performance, including responsiveness, rendering, and the user experience during slow or interrupted requests.
• Stay current with front-end trends, tools, and emerging AI technologies.
• Debug production issues across browser rendering, application state, and API integration; use telemetry and reproducible cases to find root causes and prevent regressions.
• Build and maintain deterministic unit, component, integration, and end-to-end tests for UI behavior and API contracts.
• Partner with AI and backend engineers on scenario-based evaluation of model-driven interactions, including partial results, failures, and user confirmations.
• Develop and share effective AI-assisted workflows to improve engineering productivity and code quality.
• Own customer-facing features from problem definition and design trade-offs through implementation, release, and production support.
• Collaborate with clients, designers, backend engineers, and AI engineers to scope solutions, explain trade-offs, and iterate on user needs.

Benefits

• Competitive base salary and annual bonus.
• Medical, dental, and vision insurance for employees and their families, mostly company-paid.
• Company-paid disability and life insurance.
• Optional pet insurance and identity theft protection.
• Paid parental leave for all types of parents and families.
• Equity ownership in the company.
• 401(k) plan.
• Unlimited paid time off, plus a $1,000 bonus for taking five consecutive days off.
• Flexibility to work anywhere in the world for one month a year.
• Tuition reimbursement.
• Cell phone and transportation reimbursement.
• Daily lunch from local restaurants.
• Office amenities including a full kitchen, massage chairs, and live plants.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior