Frontend Developer - RetainerDenny Portillo
Let's build and ship consistently.
With my monthly retainer, you get a senior frontend engineer who understands real-time systems, product iteration, and scalable architecture. I help teams ship features, integrate complex backend services, and improve performance without breaking structure.
From enterprise platforms (Scotiabank, Walmart) to Web3 dashboards and validator monitoring systems, I bring execution speed with production-level standards.
How it works
Flexible Monthly Hours
Predefined hours you can allocate to features, refactors, experiments, or support.
Priority Execution
Your roadmap gets scheduled capacity and faster turnaround.
Deep Product Context
I work closely with product and backend teams to align UI behavior with business logic.
Monthly Reporting
Clear summary of shipped features, technical improvements, and next priorities.
What's Included
1. Feature Development & Maintenance
Dashboards / Internal tools
Onboarding flows / Product features
Web/Mobile UI (Next.js / React / React Native)
Refactors / structured improvements
2. Backend & API Integration
REST / GraphQL integration
WebSockets / Real-time data
Auth / Payments / Smart Contracts
Data pipelines / Caching
3) UI/UX Implementation & Performance
Pixel-perfect UI from design
Design system implementation
Performance optimization (Core Web Vitals)
State management and scalability cleanup
FAQs
Retainers range from 20-70 hours per month, depending on your needs. Final scope and hours are defined during the initial consultation.
No. Retainers are structured for consistent monthly execution, and we’ll prioritize to maximize your allocated time.
Additional hours are available at a discounted rate of $80/hour.
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.
I adapt to your existing workflow, whether that is Jira, GitHub Projects, Linear, or any internal board. If needed, we can use Trello or Notion.
You receive weekly updates with a summary of completed tasks, key findings, and next priorities, plus regular check-ins to stay aligned.
Example work
Denny's other services
Starting at$5,000 /mo
Tags
Next.js
Node.js
React
Tailwind CSS
TypeScript
Vercel
Cryptocurrency & Blockchain
Frontend Engineer
Web Developer
Service provided by
Denny Portillo proSan Salvador, El Salvador
- 4
- Followers
Frontend Developer - RetainerDenny Portillo
Starting at$5,000 /mo
Tags
Next.js
Node.js
React
Tailwind CSS
TypeScript
Vercel
Cryptocurrency & Blockchain
Frontend Engineer
Web Developer
Let's build and ship consistently.
With my monthly retainer, you get a senior frontend engineer who understands real-time systems, product iteration, and scalable architecture. I help teams ship features, integrate complex backend services, and improve performance without breaking structure.
From enterprise platforms (Scotiabank, Walmart) to Web3 dashboards and validator monitoring systems, I bring execution speed with production-level standards.
How it works
Flexible Monthly Hours
Predefined hours you can allocate to features, refactors, experiments, or support.
Priority Execution
Your roadmap gets scheduled capacity and faster turnaround.
Deep Product Context
I work closely with product and backend teams to align UI behavior with business logic.
Monthly Reporting
Clear summary of shipped features, technical improvements, and next priorities.
What's Included
1. Feature Development & Maintenance
Dashboards / Internal tools
Onboarding flows / Product features
Web/Mobile UI (Next.js / React / React Native)
Refactors / structured improvements
2. Backend & API Integration
REST / GraphQL integration
WebSockets / Real-time data
Auth / Payments / Smart Contracts
Data pipelines / Caching
3) UI/UX Implementation & Performance
Pixel-perfect UI from design
Design system implementation
Performance optimization (Core Web Vitals)
State management and scalability cleanup
FAQs
Retainers range from 20-70 hours per month, depending on your needs. Final scope and hours are defined during the initial consultation.
No. Retainers are structured for consistent monthly execution, and we’ll prioritize to maximize your allocated time.
Additional hours are available at a discounted rate of $80/hour.
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.
I adapt to your existing workflow, whether that is Jira, GitHub Projects, Linear, or any internal board. If needed, we can use Trello or Notion.
You receive weekly updates with a summary of completed tasks, key findings, and next priorities, plus regular check-ins to stay aligned.
Example work
Denny's other services
$5,000 /mo