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Mid-level · 2-4 years
Open

Fullstack Developer

Freelance fullstack role building end-to-end product features across Next.js frontend, NestJS backend, and PostgreSQL for SaaS platforms and AI-enabled web apps.

What you'll do

  • Build fullstack features end-to-end: Next.js App Router frontend, NestJS API backend, and PostgreSQL data layer for SaaS platforms and AI-enabled products.

  • Design and implement REST APIs and WebSocket real-time features with proper auth, validation, error handling, and caching strategies.

  • Write and review database schemas, migrations, and optimized queries using PostgreSQL and Prisma ORM.

  • Maintain and improve existing products — fix bugs, reduce tech debt, optimize performance, and refactor for clarity during dedicated improvement time.

  • Use AI coding tools (Claude Code, Codex, Cursor, Windsurf) daily for code generation, review, testing, documentation, and research while reviewing every generated change.

  • Write comprehensive documentation: READMEs, inline comments, ADRs, and clear PR descriptions for every change.

  • Participate in mandatory code reviews via GitHub Flow PRs and collaborate with design, product, and founder stakeholders.

Job requirements

The Resonance Team builds technology products across web apps, AI, fintech, and internal tools. These are freelance, project-based roles, with preference for long-term collaborators who can take recurring projects.

Must-have

  • Strong Next.js App Router fundamentals: routing, server/client components, data fetching, and caching.

  • Solid NestJS experience: modules, controllers, services, guards, interceptors, DTO validation, and dependency injection.

  • Type-safe TypeScript with generics, utility types, and shared type patterns across frontend and backend.

  • PostgreSQL proficiency: schema design, query optimization, indexing, and migration management with Prisma ORM.

  • Production REST API design with authentication (JWT/OAuth), error handling, input validation, and rate limiting.

  • Unit testing discipline: write meaningful tests for both frontend components and backend services.

  • Tailwind CSS fluency with component-driven design systems (shadcn/ui or similar).

  • Solid Git workflow with GitHub Flow: feature branches, pull requests, mandatory code review, and conflict resolution.

  • Self-managed, clear communication, strong problem-solving, and ability to self-onboard from documentation.

AI workflow

Important note: The team has integrated AI tools into the daily workflow. Candidates must have hands-on, practical experience with AI tools, not just light or occasional usage.

  • Daily practical workflow with at least two of: Claude Code, Codex CLI, Cursor, Windsurf, or similar AI coding tools.

  • Can evaluate and choose the right AI tool for each task — code generation, refactoring, debugging, testing, or exploration.

  • Integrates agent coding tools into development workflow: context packing, task decomposition, and output validation.

  • Writes clear context, constraints, repo instructions, and acceptance criteria before asking AI to code.

  • Reviews AI-generated code critically — tests behavior, checks edge cases, and refactors rather than accepting output at face value.

  • Bonus for agentic workflows: Claude Code subagents, MCP, multi-agent orchestration, or custom CLAUDE.md configuration.

  • Understands basic responsible AI concerns: ethics, bias, fairness, and accountability.

Nice-to-have

  • Redis caching strategies for API response optimization and session management.

  • WebSocket or real-time feature experience (Socket.IO, SSE, streaming UI).

  • Docker containerization and CI/CD pipeline setup (GitHub Actions).

  • shadcn/ui and Radix UI customization beyond copy-paste.

  • State management with Zustand, Jotai, or TanStack Query.

  • AI/ML experience or interest in building AI-powered product features.

  • Side projects or portfolio demonstrating similar fullstack work.

Optional

  • Mobile experience with React Native, Expo, or NativeWind.

  • Vercel deployment and serverless function experience.

  • i18n or multi-language app experience.

  • Open-source contributions or technical blog writing.

  • Blockchain/Web3 background for fintech projects when relevant.

What you'll get

  • Task-based compensation tied to contribution and project milestones.

  • Flexible working hours — own your schedule, deliver on commitments.

  • Equipment allowance for your development setup.

  • 100% remote work with GMT+7 overlap preferred.

  • Opportunity for recurring long-term collaboration if both sides work well together.

  • Direct collaboration with design, product, founder, and engineering across shipped SaaS products.

  • A defined amount of AI tool access and token budget provided for work, experimentation, learning, and workflow optimization.

  • Modern tech stack with dedicated time for tech debt, comprehensive documentation culture, and mandatory code reviews.

Application form

Apply for this role.

Upload a CV, share a portfolio or GitHub profile, and include one concrete AI workflow example; no unpaid sample task is required.

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Resume/CV, portfolio or GitHub, email, concrete AI workflow.
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Review
Portfolio review, workflow review, short fit call.
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