👋

Hello, I'm Charlie Rios. I'm a Senior Full-Stack Software Engineer based in Amsterdam.
I build products end-to-end — from UI architecture to APIs, infra, and production deployments.

About me

Software Engineer with over 9 years of experience building and maintaining modern web and mobile applications across fintech, e-commerce, and SaaS. Skilled in React, Next.js, Node.js, Python, Java, SwiftUI, and RESTful APIs, with solid expertise in server-side rendering, WebSockets, and accessibility best practices.

What I bring: hands-on technical depth · business-oriented problem solving · clean code & UI/UX · AI-native product engineering

Featured projects

A selection of products and libraries I've designed, built, and shipped — from native macOS apps to npm packages and full-stack web platforms.

CookGPT - Gourmet Plan & Taste

iPhone/iPad native SwiftUI app — browse and edit recipes, plan meals by day or week, generate grocery lists from your schedule, and run step timers with Live Activities on the Lock Screen and Dynamic Island. Your recipes, meal plans, and shopping lists stay on device.

Swift
iOS
iPadOS

Website App Store GitHub

Token Bar

Native macOS menu bar app that unifies AI usage across Cursor, OpenAI, Anthropic, and more — track tokens, credits, spend, and burn rate without juggling provider dashboards. Includes Notification Center widgets, usage alerts, and privacy-first credential storage in the Keychain.

Swift
macOS

Website App Store GitHub

Pocket Agent

Offline-first PocketAgent monorepo: an iOS client for chat UI and Mac node pairing, plus a macOS agent node host (Telegram, roles, tools) with a shared marketing site and OKF specs. Same bundle ID across iPhone, iPad, and Mac targets.

Swift
iOS
macOS
SwiftUI

Website App Store GitHub

dropafile

Drop a file. Everyone gets it live. Ephemeral, live-session file sharing on Cloudflare Workers — spin up a room, share a link or QR code, and let connected peers download in real time. WebSocket signaling on the edge; file bytes flow peer-to-peer in the browser.

Cloudflare
Hono
React
TypeScript

Website GitHub

Email Signature Editor

Schema-driven email signature builder with a guided template flow, live HTML preview, and one-click copy into Gmail. Import your profile from LinkedIn to pre-fill fields, then customize in the visual template editor.

React
Vite
Tailwind CSS
shadcn/ui

Website GitHub

Lizard UI

React component library with shadcn-style primitives and Tailwind-native glass styling — 23 runtime-swappable color themes, light/dark/system modes, and tree-shakeable ESM + CJS builds with full TypeScript declarations.

React
TypeScript
Tailwind CSS
npm

Website GitHub

My skills

AI
Astro
AWS
CSS
Cloudflare Workers
Ethers.js
Express
FastAPI
Framer Motion
Git
GraphQL
Hono
HTML
Java
JavaScript
MongoDB
Next.js
Node.js
OCI
PHP
Prisma
Python
React
React Native
React Router v7
Redux
RSC
SQL
Shadcn UI
Supabase
Swift
Tailwind
TanStack Query
TypeScript
tRPC
Vercel
Vite
WCAG 2.2
WebSockets

My Experience

Frontend Lead & Product Engineer

Timbal Tech, S.L. (Timbal AI)

Barcelona (hybrid), Spain

November 2025 - Present

Next.jsReactRSCTypeScriptShadcn UITanStack QueryFastAPIAI

Architected AI-native user experiences and multi-agent workflows using an in-house framework to power asynchronous, real-time streaming interfaces for enterprise clients.
Led end-to-end frontend architecture for a flagship AI-powered ERP, leveraging Next.js (App Router), React Server Components, TypeScript, and Shadcn UI.
Orchestrated high-throughput data flows using TanStack Query/Table and FastAPI backends, optimizing client-side caching, optimistic UI updates, and payload efficiency.
Defined frontend standards and design systems across client engagements to accelerate delivery while enforcing type safety, accessibility, and performance baselines.
Bridged product engineering and AI core teams to translate LLM outputs, chain-of-thought processes, and structured data into intuitive human-in-the-loop interfaces.

Frontend Lead & Product Engineer

Timbal Tech, S.L. (Timbal AI)

Barcelona (hybrid), Spain

November 2025 - Present

Next.jsReactRSCTypeScriptShadcn UITanStack QueryFastAPIAI

Architected AI-native user experiences and multi-agent workflows using an in-house framework to power asynchronous, real-time streaming interfaces for enterprise clients.
Led end-to-end frontend architecture for a flagship AI-powered ERP, leveraging Next.js (App Router), React Server Components, TypeScript, and Shadcn UI.
Orchestrated high-throughput data flows using TanStack Query/Table and FastAPI backends, optimizing client-side caching, optimistic UI updates, and payload efficiency.
Defined frontend standards and design systems across client engagements to accelerate delivery while enforcing type safety, accessibility, and performance baselines.
Bridged product engineering and AI core teams to translate LLM outputs, chain-of-thought processes, and structured data into intuitive human-in-the-loop interfaces.

Spearheaded core application modernization, executing a full-stack migration to React 19, React Router v7, Vite, and Node.js 23 to eliminate legacy technical debt.
Implemented hybrid rendering architectures (SSR/SSG) with Next.js and advanced routing protocols, significantly improving initial load times (FCP/LCP) and SEO performance.
Built real-time event ticketing features utilizing WebSockets for live inventory state synchronization and seamless transactional flows.
Enforced strict WCAG 2.2 AA accessibility standards and component modularity across high-traffic consumer touchpoints.

Frontend Lead (React)

Aplicaciones Web Mardo, S.L. (CODETICKETS)

Mataró (hybrid), Spain

November 2024 - November 2025

React 19React Router v7Next.jsNode.js 23ViteWebSocketsWCAG 2.2

Frontend Lead (React)

Aplicaciones Web Mardo, S.L. (CODETICKETS)

Mataró (hybrid), Spain

November 2024 - November 2025

React 19React Router v7Next.jsNode.js 23ViteWebSocketsWCAG 2.2

Spearheaded core application modernization, executing a full-stack migration to React 19, React Router v7, Vite, and Node.js 23 to eliminate legacy technical debt.
Implemented hybrid rendering architectures (SSR/SSG) with Next.js and advanced routing protocols, significantly improving initial load times (FCP/LCP) and SEO performance.
Built real-time event ticketing features utilizing WebSockets for live inventory state synchronization and seamless transactional flows.
Enforced strict WCAG 2.2 AA accessibility standards and component modularity across high-traffic consumer touchpoints.

Senior Fullstack Developer & UI/UX Designer

Pixelimperium, S.L. / Freelance

Ibiza (remote), Spain

November 2022 - September 2024

HonoNext.jsTypeScriptSupabaseVercelAWSCloudflare Workers

Engineered edge-first API layers and web applications using Hono, Next.js, TypeScript, and Supabase, achieving sub-100ms response times globally.
Designed and built scalable, accessible design systems from wireframes to production code, unifying brand identity across diverse multi-tenant web platforms.
Automated CI/CD pipelines and multi-cloud deployments across Vercel, AWS, and Cloudflare Workers to deliver zero-downtime releases.

Senior Fullstack Developer & UI/UX Designer

Pixelimperium, S.L. / Freelance

Ibiza (remote), Spain

November 2022 - September 2024

HonoNext.jsTypeScriptSupabaseVercelAWSCloudflare Workers

Engineered edge-first API layers and web applications using Hono, Next.js, TypeScript, and Supabase, achieving sub-100ms response times globally.
Designed and built scalable, accessible design systems from wireframes to production code, unifying brand identity across diverse multi-tenant web platforms.
Automated CI/CD pipelines and multi-cloud deployments across Vercel, AWS, and Cloudflare Workers to deliver zero-downtime releases.

Developed real-time fintech applications for tracking market stocks and foreign exchange data using React Native, Swift, and Node.js.
Integrated Web3 data providers and decentralized infrastructure using Ethers.js to stream live token pricing and smart contract telemetry.
Managed cloud infrastructure and CI/CD pipelines on AWS and Oracle Cloud Infrastructure (OCI) with Cloudflare edge caching.

iOS Software Engineer

DR Finantrust, S.L. (INBISA)

Molins De Rei, Spain (hybrid)

May 2022 - September 2022

React NativeSwiftNode.jsEthers.jsAWSOCICloudflare

iOS Software Engineer

DR Finantrust, S.L. (INBISA)

Molins De Rei, Spain (hybrid)

May 2022 - September 2022

React NativeSwiftNode.jsEthers.jsAWSOCICloudflare

Developed real-time fintech applications for tracking market stocks and foreign exchange data using React Native, Swift, and Node.js.
Integrated Web3 data providers and decentralized infrastructure using Ethers.js to stream live token pricing and smart contract telemetry.
Managed cloud infrastructure and CI/CD pipelines on AWS and Oracle Cloud Infrastructure (OCI) with Cloudflare edge caching.

Fullstack Developer | Software Engineer

Businessprinter, S.L.

Hospitalet de Llobregat, Spain (hybrid)

June 2020 - May 2022

ReactNode.jsPHPJavaAWS

Tech-led a 5-person engineering team, managing delivery schedules and architecting full-stack B2B platforms using React, Node.js, PHP, and Java.
Provisioned and maintained cloud environments on AWS, implementing containerized workflows and monitoring for high-availability production services.

Fullstack Developer | Software Engineer

Businessprinter, S.L.

Hospitalet de Llobregat, Spain (hybrid)

June 2020 - May 2022

ReactNode.jsPHPJavaAWS

Tech-led a 5-person engineering team, managing delivery schedules and architecting full-stack B2B platforms using React, Node.js, PHP, and Java.
Provisioned and maintained cloud environments on AWS, implementing containerized workflows and monitoring for high-availability production services.

Developed and maintained client websites and applications, building strong foundations in JavaScript, HTML/CSS, SQL, and evolving toward React-based frontends.

Software Engineer (Junior)

Magnum Object, S.L.

Cornellà, Spain (on-site)

May 2017 - June 2020

ReactJavaScriptHTMLCSSSQL

Software Engineer (Junior)

Magnum Object, S.L.

Cornellà, Spain (on-site)

May 2017 - June 2020

ReactJavaScriptHTMLCSSSQL

Developed and maintained client websites and applications, building strong foundations in JavaScript, HTML/CSS, SQL, and evolving toward React-based frontends.