Jonathan Ballona Sanchez
Software Engineer from Bay Area, CA
I build fast, break fast, fix fast, ship fast. Cracked engineer who lives to learn.
Skills
Jul 2024 - Feb 2025
Software Engineering Resident
Headstarter AI
• Crafted and deployed 5+ AI apps using RAG, OpenAI, Pinecone, and Stripe, achieving 98% accuracy with 450+ total users
• Developed a support agent with RAG, OpenAI, and Pinecone, handling 1,000+ queries weekly, boosting accuracy by 40%
• Led a team of 4 engineers using MVC patterns and agile, dedicating 60+ hours to complete 14 projects in 2-week sprints
Jul 2024 - Sep 2024
Software Engineering Intern
Pixeland Technologies Inc
• Created a scalable virtual office platform with React, Redux, and Firebase, boosting engagement by 30% across 10 teams
• Engineered real-time sync with Firebase, improving interactions for 2,000+ users with 20% reduced latency
• Developed WebRTC server with Express, optimizing video calls, cutting setup time by 30%, and supporting 500+ calls daily
Feb 2024 - Apr 2024
Software Engineering Intern
Lob
• Implemented authentication system with React and Auth0, reducing unauthorized access by 3% for 10,000+ users
• Optimized PostgreSQL and ExpressJS queries, reducing response time by 50% for 5,000+ active users
• Enhanced React components and ExpressJS code, improving page load times by 15% for 7,500+ users
Jul 2023 - Dec 2023
Software Engineering Intern
Sweep
• Built automated document processing application with Docker and Flask, boosting efficiency by 40% for 1,000+ PDFs daily
• Integrated gpt-3.5 turbo powered virtual assistant for data insights, reducing errors by 20% in 3,000+ reviews weekly
• Devised a text compression algorithm, cutting file sizes by 30% and increasing speed by 40% for 2,000+ transfers daily
Jun 2023 - Aug 2023
Software Engineering Intern
Open Avenues (Remix Labs)
• Connected 5+ external APIs using the RemixBuilder no-code platform, unlocking access to over 10k data points weekly
• Automated data analysis tasks via RemixBuilder’s no-code interface, reducing manual report preparation time by 15%
• Implemented automated data validation rules with RemixBuilder’s tools, improving data accuracy by 30%
Featured Projects
VALLM
LLM Evaluation on real web content
Vallm.chat
Multi-model chat/conversation branching
Recent Posts
Building Server-Side API Key Encryption with Convex and Node.js Crypto
A production-ready guide to securely encrypting user provided API keys with per user AES-256-GCM encryption and scrypt key derivation using Convex and Node.js—without ever storing plaintext secrets.
Jan 2026
Evaluating LLM Responses with RAG and DeepEval
Built a scalable API for evaluation 6+ LLM responses based off of scraped content
Apr 2025