Adam Ballai

Replit Agent is free tomorrow for everyone starting at 5am PST Show use what you can build in 24 hours And Replit is turning10! A trip down the memory lane on what got us here

I regret to inform you that Ask Jeeves is dead. The site closed yesterday. Web 1.0 lost another founder. Ask Jeeves: 3 June 1996 - 1 May 2026. Send no memes.

Replit left San Francisco for Foster City. The "why" we're leaving is boring, sad, and predictable (crime, dysfunction, etc), so instead let me tell you why we chose Foster City. Foster City embodies the American post-war optimism and the long-lost California pro-growth mentality. in 1958 businessman Jack Foster set out to build "a master-planned community concept"; in 1960 bought Brewer Island, a largely undeveloped land used for salt evaporation and dairy farming; in 1961 started building, and in 1964, the first family moved in. By 1966, more than 5,000 people were living there. Can you imagine how long it would take to build such a project today? The city is also known for its innovative engineering, particularly its "Venice-like" lagoon system. Instead of employing massive landfills to elevate the terrain for development, engineers devised a system of lagoons that provided essential drainage and a super cool aesthetic landscape. Finally, the city is super livable. When Haya and I moved to California, we first took residence there and, in fact, incorporated Replit here. Our first bank was Wells Fargo, a few steps from our new office. It's relatively affordable compared to the rest of the Bay Area and has a healthy mix of residential, commercial, and recreational spaces. Downtown San Mateo is a bridge away, a fun place to hang out or live. Finally, in the Bay Area, almost every town has an associated iconic tech company. When you think of Mountain View, you think of Google; when you think of Cupertino, you think of Apple. My hope is that in the future, when you think of Foster City, you'll think of Replit.

Vibe coding is changing how software gets built. But as AI agents write more of our code, the question security teams are asking has shifted from "Can AI build this?" to "Can I trust what AI builds?". At Replit, we believe the answer has to be yes, not through blind faith, but through architecture. Every layer of the Replit infrastructure where customer code runs, from the development sandbox to the production deployment, is designed with defense in depth. The Replit platform itself, our control plane, is also implemented with these principles in mind. No single control is the last line of defense. Every layer assumes the one above it might fail. This thread is a detailed walkthrough of how we think about security across the stack, written for the people who need to evaluate it: CISOs, security engineers, and teams considering Replit for production workloads. 🧵