Luca Rossi is an Italian software engineer, entrepreneur, and writer based in Rome who turned a side project into one of the world's most-read engineering leadership newsletters. After co-founding and scaling travel startup Wanderio to 25M+ customers over eight years, he launched Refactoring in 2020 - a newsletter covering engineering management, software teams, and tech leadership. It now reaches 172,000+ subscribers, ranks in the top 10 Substack business newsletters, and generates approximately $300K/year in revenue, all operated solo. He also hosts the Refactoring Podcast, featuring guests like DHH, Kent Beck, and Camille Fournier, and in 2025 released Tolaria, a free open-source macOS knowledge base app built entirely with AI coding tools.
Nicola Ballotta is an Italian engineering leader with 25+ years of internet industry experience, currently serving as Director of Cloud at Namecheap where he built EasyWP — one of the world's most affordable managed WordPress hosting platforms — from prototype to production. He is best known as the creator of The Hybrid Hacker, a newsletter that grew from zero to 30,000 subscribers in 18 months before being acquired by Refactoring in June 2024. The combined publication now reaches 120,000+ readers and serves a 900+ member private community of engineering leaders.
Charlie Guo is a Stanford and YC alum who turned a personal obsession with AI into a 23,000-subscriber newsletter and a Developer Experience role at OpenAI. Through Artificial Ignorance at ignorance.ai, he writes at the intersection of software engineering and artificial intelligence - cutting through hype to deliver practical, hands-on insights for builders. He has co-founded multiple startups (ClassOwl, FanHero, Crowdmade), published a book of startup interviews called Unscalable, and created a widely-used Python library for Gmail with 1.8k GitHub stars - all while teaching himself AI engineering through relentless experimentation.
Chip Huyen is a Vietnamese-American computer scientist, author, and educator who turned a rejection letter from Stanford into a three-year around-the-world journey, two bestselling Vietnamese travel books, and eventually a second application that got her in. She went on to teach at Stanford, build ML infrastructure at NVIDIA and Netflix, co-found Claypot AI, and write two of the most-read technical books on machine learning systems in production - 'Designing Machine Learning Systems' (2022) and 'AI Engineering' (2025). Her newsletter and blog are required reading for anyone building serious AI products.