---
title: "Home"
description: "Cesar Alvarenga — Technical Lead, AI at Arena. Current projects, recent writing, and what he is building with LLMs and agents."
canonical: https://cesarwilliam.com/
---

# Cesar William Alvarenga

Hey, I'm Cesar. Technical Lead, AI building intelligent products with LLMs, agents, and real-time experiences.

Working with: Python, LangChain, LangGraph, MCP, TypeScript, React.

## Featured projects

### [World Cup 2026](https://cesarwilliam.com/worldcup)

Companion site for the World Cup 2026 — live scores, AI predictions, match schedules and standings, localized across 5 languages. Built with Next.js, next-intl, and Tailwind, integrated into this site via Next.js Multi-Zones.

Tags: Next.js, next-intl, Tailwind, i18n, Vercel

### [My Avatar](https://myavatar.ai)

AI-powered platform to create your digital avatar. Engage your audience with text, voice, and video conversations that reflect your personality. Built with LangChain, LangGraph, and MCP.

Tags: LangChain, LangGraph, MCP, Python, GPT

## Projects

- [NFL Live Hub](https://cesarwilliam.com/nfl-live-hub): A Chrome extension that adds NFL Live Game and Score Center to your browser. Real-time NFL scores, stats, game recaps, standings, and fan chat in one extension.
- [Olympic Games Paris 2024 Chrome Extension](https://cesarwilliam.com/olympic-games-paris-2024): A Chrome extension that brings the excitement of the Olympic Games Paris 2024 to the users, powered by VideoJS, shadcn/ui, Preact, and Vite.
- [react-input-emoji](https://github.com/cesarwbr/react-input-emoji) — JavaScript, 109 stars, 59 forks: A React input with an option to pick emojis 😍 😜 😂 😛
- [google-analytics-element](https://github.com/cesarwbr/google-analytics-element) — HTML, 32 stars, 11 forks: Web Component wrapper for Google Analytics code using Polymer
- [arena-chat-sdk](https://github.com/stationfy/arena-chat-sdk) — TypeScript, 9 stars, 2 forks: Arena offers the best engagement tools to grow your website. Liveblog, Live Chat and Wordpress widgets to increase traffic and earn revenue.
- [loadx](https://github.com/cesarwbr/loadx) — JavaScript, 4 stars, 1 forks: Load image, CSS, and JavaScript files, using the Promise API.

## Recent posts

- [Markdown Guide for Developers](https://betterprogramming.pub/markdown-guide-for-developers-6d44f1633cbe?source=rss-e6184c596078------2) — Mon Mar 21 2022
- [Design Patterns In TypeScript — Adapter](https://cesarwilliam.medium.com/design-patterns-in-typescript-adapter-61f805ce7c82?source=rss-e6184c596078------2) — Sun Oct 24 2021
- [Design Patterns In TypeScript — Strategy](https://cesarwilliam.medium.com/design-patterns-in-typescript-strategy-480b27d0d0f6?source=rss-e6184c596078------2) — Sun Jul 04 2021
- [How to Create a Video Chat With React, TypeScript, and WebRTC](https://medium.com/geekculture/how-to-create-a-video-chat-with-react-typescript-and-webrtc-8a70f6159cdc?source=rss-e6184c596078------2) — Mon Jun 28 2021
- [Design Patterns In TypeScript — Factory](https://cesarwilliam.medium.com/design-patterns-in-typescript-factory-d870a00b0f31?source=rss-e6184c596078------2) — Sat Jun 19 2021
- [Design Patterns In TypeScript — Observer](https://medium.com/swlh/design-patterns-in-typescript-observer-de1d90674eef?source=rss-e6184c596078------2) — Wed Jun 09 2021
- [Design Patterns In TypeScript — Singleton](https://levelup.gitconnected.com/design-patterns-in-typescript-singleton-d165e8058cb7?source=rss-e6184c596078------2) — Sun Jun 06 2021
- [How to Solve Constraint Satisfaction Problems (CSPs) With  AC-3 Algorithm in Python](https://medium.com/swlh/how-to-solve-constraint-satisfaction-problems-csps-with-ac-3-algorithm-in-python-f7a9be538cfe?source=rss-e6184c596078------2) — Fri Jan 22 2021

## More

- [About](https://cesarwilliam.com/about)
- [Uses](https://cesarwilliam.com/uses)
- [URL index for LLMs](https://cesarwilliam.com/llms.txt)