Senior Full-Stack & Mobile Developer / Technical Lead — Startup Product Development

Job Type:Remote, Part-Time Contract Experience Level: Senior / Expert Commitment: 13 Hours per Week Initial Duration: 4 Weeks, With Potential for Extension Budget: $400 - 600 for an initial 4-week engagement (13 hours per week). About the Role We are an early-stage technology startup seeking an experienced Senior Full-Stack & Mobile Developer to help lead our existing development team and bring our web and mobile applications to a successful public launch. Our applications are in the final stages of development. We are looking for a highly skilled engineer who can take technical ownership, evaluate the current state of the project, identify remaining development needs, and ensure the applications are secure, stable, fully functional, and ready for production. This position requires someone who can combine hands-on software engineering with technical leadership, code reviews, development planning, and team coordination. The selected candidate will work closely with our existing developers, providing direction, reviewing their work, resolving complex technical issues, and ensuring the team delivers high-quality results. Key Responsibilities Technical Leadership & Team Management - Provide technical leadership and guidance to our existing development team. - Review, approve, and maintain high-quality code across web and mobile applications. - Assign tasks, establish priorities, and coordinate development activities. - Mentor junior developers and assist with technical challenges. - Identify development bottlenecks and recommend effective solutions. - Establish coding standards, testing procedures, and development best practices. - Ensure tasks are completed efficiently and meet defined quality standards. Full-Stack & Mobile Development - Review and improve existing frontend and backend architecture. - Develop, debug, and optimize applications using React, Next.js, TypeScript, Node.js, and React Native. - Work with Expo and related mobile development tools. - Review API integrations, database operations, authentication, and application security. - Resolve critical bugs and performance issues. - Ensure reliable functionality across web, iOS, and Android platforms. - Support the development team with hands-on coding when necessary. Product Finalization & Launch - Conduct a comprehensive technical review of the existing applications. - Identify and prioritize remaining development tasks. - Coordinate final bug fixes, quality assurance, and performance improvements. - Prepare production-ready web and mobile applications. - Oversee production builds, deployment configurations, and release preparation. - Manage technical aspects of Apple App Store and Google Play publishing. - Address technical issues discovered during testing or app-store review. - Support a smooth public launch and initial post-launch stabilization. Project Planning & Accountability - Develop a structured plan for completing outstanding development work. - Maintain clear task assignments, priorities, and progress tracking. - Conduct regular code reviews and technical meetings. - Provide weekly progress reports and identify potential risks. - Communicate technical decisions and project blockers clearly. - Ensure completed work is properly tested, documented, and reviewed. - Take ownership of technical delivery and coordinate the team toward agreed milestones. Required Qualifications - 5+ years of professional full-stack software development experience. - Strong expertise in React, Next.js, TypeScript, and Node.js. - 3+ years of React Native and Expo development experience. - Proven experience publishing applications to the Apple App Store and Google Play. - Strong knowledge of PostgreSQL, REST APIs, and backend architecture. - Experience with GitHub, pull requests, and collaborative code review. - Understanding of cloud infrastructure, CI/CD, and production deployment. - Strong debugging, performance optimization, and application security skills. - Previous experience leading or mentoring software developers. - Excellent communication, organization, and problem-solving abilities. Preferred Qualifications - Experience working with early-stage startups. - Experience taking existing MVPs through production launch. - Familiarity with Google Cloud Platform, Prisma, and Expo EAS. - Experience with third-party integrations and payment systems. - Knowledge of automated testing and release management. - Ability to make practical technical decisions under tight deadlines. Working Arrangement This is a remote, part-time position requiring 13 hours per week. The Senior Developer will collaborate with our existing development team, providing technical oversight, code reviews, task assignments, and hands-on engineering support. The initial engagement is four weeks, with opportunities for continued collaboration based on performance and project needs. Ideal Candidate We are looking for someone who is proactive, dependable, technically experienced, and comfortable taking responsibility for a project approaching launch. The ideal candidate can quickly understand an existing codebase, identify what needs to be completed, guide other engineers effectively, and help transform nearly finished applications into reliable, production-ready products. We value engineers who demonstrate results through working software, clear communication, and consistent technical leadership. How to Apply Please provide: 1. A summary of your full-stack and mobile development experience. 2. Links to applications you have successfully launched. 3. Examples of previous technical leadership or team mentoring. 4. Your experience with React Native, Expo, Next.js, and production deployment. 5. Your approach to completing and launching an existing application while leading a small development team. 6. Confirmation of your availability for 13 hours per week.