I will be your senior frontend engineer for vc yc startups


About this gig
Senior Frontend Execution Retainer
Ship consistently with a senior frontend engineer focused on real-time systems, scalable architecture, and fast product iteration. Experience includes enterprise platforms like Scotiabank and Walmart, plus Web3 dashboards and validator monitoring desktop apps.
What's Included
1. Feature Development & Maintenance
- Dashboards & internal tools
- Onboarding flows & product features
- Web & mobile UI (Next.js / React / React Native)
- Refactors & structural improvements
2. Backend & API Integration
- REST & GraphQL
- WebSockets & real-time systems
- Auth, payments & smart contracts
- Data pipelines & caching strategies
3. UI/UX & Performance
- Pixel-perfect implementation from design
- Design system architecture
- Core Web Vitals optimization
- State management & scalability cleanup
Or anything feasible within frontend/UI scope.
How It Works
- Flexible Monthly Hours Predefined hours allocated to roadmap priorities.
- Priority Execution Dedicated capacity and faster turnaround.
- Deep Product Context Tight collaboration with product and backend teams.
- Monthly Reporting Clear summary of shipped features and next priorities.
Get to know Denny Portillo
Senior Fullstack Developer
- FromEl Salvador
- Member sinceJan 2026
Languages
English, Spanish
My Portfolio
Other Software Development Services I Offer
FAQ
How many hours are included in a retainer?
Retainers range from 20-80 hours per month, depending on your needs. Final scope and hours are defined during the initial consultation.
Do unused hours carry over?
No. Retainers are structured for consistent monthly execution, and we’ll prioritize to maximize your allocated time.
What development work can you handle?
I handle Next.js and React development, mobile integrations with React Native and Capacitor, API and smart contract integrations, real time systems, performance optimization, architecture improvements, and code reviews. Not sure? Just ask.
What if I need more hours in a month?
Additional hours are available at a discounted rate.
