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I am a detail-oriented Front-End Developer with a strong focus on building deterministic web applications based on strict specifications. I specialize in Next.js, Tailwind CSS, jsPDF, and PapaParse to deliver clean, functional user interfaces and robust data processing tools. I have proven ability to implement complex logic, including CSV data validation, dynamic scoring computations, and automated PDF report generation. I am dedicated to exact execution of provided requirements without unnecessary product redesigns. I deliver high-quality, bug-free code within agreed timelines, ensuring seamless user experiences and reliable dashboard visualizations.…I am a detail-oriented Front-End Developer with a strong focus on building deterministic web applications based on strict specifications. I specialize in Next.js, Tailwind CSS, jsPDF, and PapaParse to deliver clean, functional user interfaces and robust data processing tools. I have proven ability to implement complex logic, including CSV data validation, dynamic scoring computations, and automated PDF report generation. I am dedicated to exact execution of provided requirements without unnecessary product redesigns. I deliver high-quality, bug-free code within agreed timelines, ensuring seamless user experiences and reliable dashboard visualizations.

Rijyel Sevilleno

Full Stack Developer, Web Developer, Programmer, +7

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I am a detail-oriented Front-End Developer with a strong focus on building deterministic web applications based on strict specifications. I specialize in Next.js, Tailwind CSS, jsPDF, and PapaParse to deliver clean, functional user interfaces and robust data processing tools. I have proven ability to implement complex logic, including CSV data validation, dynamic scoring computations, and automated PDF report generation. I am dedicated to exact execution of provided requirements without unnecessary product redesigns. I deliver high-quality, bug-free code within agreed timelines, ensuring seamless user experiences and reliable dashboard visualizations.…I am a detail-oriented Front-End Developer with a strong focus on building deterministic web applications based on strict specifications. I specialize in Next.js, Tailwind CSS, jsPDF, and PapaParse to deliver clean, functional user interfaces and robust data processing tools. I have proven ability to implement complex logic, including CSV data validation, dynamic scoring computations, and automated PDF report generation. I am dedicated to exact execution of provided requirements without unnecessary product redesigns. I deliver high-quality, bug-free code within agreed timelines, ensuring seamless user experiences and reliable dashboard visualizations.

Available to hire

I am a detail-oriented Front-End Developer with a strong focus on building deterministic web applications based on strict specifications. I specialize in Next.js, Tailwind CSS, jsPDF, and PapaParse to deliver clean, functional user interfaces and robust data processing tools.

I have proven ability to implement complex logic, including CSV data validation, dynamic scoring computations, and automated PDF report generation. I am dedicated to exact execution of provided requirements without unnecessary product redesigns. I deliver high-quality, bug-free code within agreed timelines, ensuring seamless user experiences and reliable dashboard visualizations.

Skills

Experience Level

Expert

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Intermediate

Language

English

Fluent

Work Experience

Senior Full-Stack Developer at Novatrade

June 1, 2023 - September 1, 2025

Architected large-scale SaaS platforms using React, Next.js, TypeScript, Node.js, Django REST, and Ruby on Rails; migrated and customized WordPress into a headless CMS architecture integrated with Next.js, improving SEO and performance. Implemented Umbraco CMS modules for enterprise clients with multi-language support. Built automation pipelines connecting APIs, databases, SaaS tools, and internal systems; created scheduled scraping workflows with automated Google Sheets reporting. Integrated DataForSEO, Firebase, HubSpot, Google Sheets, and custom APIs; automated keyword extraction and SEO reporting workflows. Built secure REST + GraphQL APIs with caching, throttling, and error-handling layers; developed AI automation workflows using OpenAI and LangChain. Designed multi-tenant authentication with OAuth2, JWT, RBAC, MFA, and scoped access controls. Designed AWS infrastructure with CloudFront, S3, RDS, Secrets Manager, API Gateway, and VPC isolation. Built CI/CD pipelines with GitHub Ac

Full-Stack Developer at LearnWithSocrates

October 1, 2021 - April 1, 2023

Built core platform features using React, Next.js SSR/SSG, Django REST, Java, and .NET integrations. Developed multi-tenant learning modules, curriculum engines, and student progress workflows. Integrated Stripe, PayPal, and SendGrid for billing, renewals, invoices, and communications. Designed relational PostgreSQL schemas, optimized queries, and implemented Redis caching. Built real-time analytics dashboards with WebSockets and Chart.js; developed background workers for notifications, content processing, and report generation. Created reusable UI frameworks and shared components; implemented secure API gateways, token refresh flows, and access policies for multiple roles. Established automated CI/CD pipelines with GitHub Actions and AWS server infrastructure; achieved 90%+ test coverage with Jest, Pytest, Cypress, and API integration suites. Documented architecture and released features aligned with product roadmaps.

Software Engineer (Full-Stack & Cloud) at Veggie LLC

June 1, 2019 - August 1, 2021

Developed e-commerce web and mobile apps using React.js, React Native, Node.js, and FastAPI. Built TensorFlow-based product recommendation engines for personalization and ranking. Designed backend microservices supporting checkout, inventory, product discovery, and suppliers. Deployed large-scale workloads to AWS ECS/EKS with load balancers, autoscaling, and rolling updates. Designed DynamoDB and MongoDB schemas with optimized indexing and partition strategies; implemented real-time order tracking and customer messaging via WebSockets. Built dashboards for forecasting, product management, logistics, and real-time analytics. Integrated Stripe/PayPal payments with secure tokenization and retry logic. Implemented SSR patterns, caching, prefetching, and lazy loading for performance. Automated infrastructure with Terraform, Docker, and multi-environment provisioning; created event-driven pipelines using SQS/SNS. Reduced AWS costs by ~25% via right-sizing and lifecycle policies. Implemented

Freelancer at Upwork (Remote)

October 1, 2025 - Present

Completed two full-stack automation projects using n8n to streamline workflows for clients. Developed highly efficient API integrations for clients in the e-commerce sector, improving data processing speed by 30%.

Senior Full-Stack Engineer at Novatrade (Japan, Remote)

June 1, 2023 - September 1, 2025

Led the design and implementation of an enterprise web application using Laravel and Vue.js, handling 10,000+ users and 100,000+ transactions per day. Optimized existing database queries and application logic, reducing page load times by 25%. Implemented security protocols including OAuth2 and JWT for secure user authentication, improving data protection and user trust. Managed cloud infrastructure on AWS, reducing infrastructure costs by 15% while ensuring 99.99% uptime.

Full-Stack Developer at LearnWithSocrates (USA, Remote)

October 1, 2021 - April 1, 2023

Developed end-to-end web applications using Laravel, FastAPI, and React, leading to a 40% improvement in user engagement. Designed API endpoints for secure user registration and authentication, leveraging OAuth2 and JWT to enforce robust security. Implemented automated deployment pipelines using GitLab CI/CD, reducing release time by 20%.

Software Engineer at Veggie LLC (Japan, Remote)

June 1, 2019 - August 1, 2021

Built and maintained e-commerce websites using Laravel and Shopify API, increasing customer orders by 30%. Designed and integrated RESTful APIs for real-time data exchange between platforms, improving response times by 40%. Assisted in setting up AWS and Docker for scalable, cost-effective web hosting.

Bubble SaaS Developer at Novatrade

June 1, 2023 - December 1, 2025

Led development of scalable SaaS dashboard platforms in Bubble.io from concept to deployment; designed and implemented complex survey engines; developed custom scoring logic to automate survey result evaluations; translated design briefs into pixel-perfect responsive interfaces; built dynamic dashboards with charts and data tables; managed Bubble database architecture, ensuring relational integrity; integrated third-party APIs and plugins to extend functionality; delivered plug-and-play SaaS products with rapid time-to-market; optimized performance and implemented authentication and access controls; collaborated under NDA; conducted testing and debugging; iterated dashboards and scoring parameters in real time; documented application logic and data models.

No-Code App Developer at LearnWithSocrates

October 1, 2021 - April 1, 2023

Designed and developed Bubble-based web applications for user-centric SaaS platforms; created interactive survey modules with conditional branching and dynamic questioning logic; programmed advanced scoring systems for instant metric display; developed admin dashboards with real-time analytics and user management; customized UI/UX from provided wireframes; ensured responsive experiences across devices; integrated external payment gateways and email tools via API connections; streamlined data collection processes; managed project timelines and deliverables; implemented data security protocols; troubleshot complex workflows and optimized database queries for faster dashboard rendering; collaborated with cross-functional teams to refine requirements and build briefs.

Junior Bubble Developer at Veggie LLC

June 1, 2019 - August 1, 2021

Assisted in Bubble.io web application development, focusing on frontend design and workflow logic; built foundational survey forms and basic scoring mechanisms; configured dashboard layouts to display KPIs and survey summaries; translated static designs into functional Bubble pages; supported database setup and data capture; participated in testing and debugging; learned best practices for no-code development and performance optimization; assisted in integrating third-party plugins; provided technical support and maintenance; documented application workflows and data schemas.

Front-End Developer at Novatrade (Japan, Remote)

June 1, 2023 - December 1, 2025

Built deterministic front-end web applications strictly adhering to fully defined technical specifications. Developed robust front-end architectures with Next.js and Tailwind CSS. Implemented client-side CSV upload and parsing with PapaParse, performed strict data validation, computed multi-domain scores, created dynamic dashboards with real-time scores and heatmaps, and generated structured multi-page PDFs using jsPDF. Ensured performance optimization and adherence to project briefs, with thorough cross-browser testing and reusable component libraries.

Next.js Developer at LearnWithSocrates (USA, Remote)

October 1, 2021 - April 1, 2023

Developed data-driven web applications using Next.js and React, implementing UI with Tailwind CSS. Integrated PapaParse for large CSV uploads with robust error handling, implemented complex client-side scoring logic, and generated 25+ page PDF reports using jsPDF. Built interactive dashboards with heatmaps and data grids, maintaining strict focus on clean execution and cross-browser compatibility while managing large datasets and QA processes.

Junior Web Developer at Veggie LLC (Japan, Remote)

June 1, 2019 - August 1, 2021

Assisted in building web interfaces using React and Next.js according to strict guidelines. Applied Tailwind CSS for precise UI alignment, supported CSV parsing features with PapaParse, wrote client-side validation scripts, contributed to dashboard widgets and basic charts, and helped develop automated reporting features with JavaScript libraries like jsPDF. Maintained coding standards and delivered deterministic results within deadlines.