The Architecture of Vibe Coding: Inside Bolt.new's Stack

Over the past year, the cutting edge of software development has kind of flipped: Engineers are increasingly writing specs instead of code, directing agentic tools to build and ship systems. At the same time, product managers are skipping specs altogether, using vibe coding to turn ideas directly into working software.

I sat down in San Francisco with Eric Simons, founder and CEO of StackBlitz, whose team created Bolt and, in the process, defined the vibe-coding category.

In this conversation, we explore how that shift happened, why it spread so quickly, the browser-native technology that makes it possible, and how it is reshaping who builds software, how decisions get made, and how software actually gets shipped.

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In the video:

• Bolt’s Architecture  
    A clear look at the WebAssembly architecture that lets Bolt run a full Node.js environment locally, delivering near-instant feedback while avoiding the cost and latency of cloud VMs.

• How Bolt Pivoted into Hyper-growth  
  How they spent ~7 years building a browser-based IDE and WebContainers tech to reach a $700K ARR and how they went about their pivot.

• Is AI Code a Toy or Production Software?  
    A candid discussion of the biggest criticism of vibe coding: whether AI-generated code is throwaway spaghetti, whether software itself is splitting into long-lived systems and fast, “good enough” internal tools or if the worlds will converge. Will vibe coded apps become the “spec” for an agentic coding workflow, or will vibe coded apps usurp much of traditionally developed sorftware?

• Product Managers Who Ship Code  
   How non-engineers can now generate and deploy full-stack apps on their own, and why this is creating tension for senior engineers who worry about maintaining AI-generated systems.

• Security, Enterprises, and Shadow AI  
   Why running everything in a browser sandbox matters for security teams, how it reduces the risk of leaking sensitive data to public models, and what an on-prem version of Bolt looks like.

• What Engineers Actually Do Now  
   Why the job is shifting from writing code to designing systems, reviewing outputs, and managing agents, and why automated tools for testing, security, and code review are becoming non-optional as code generation explodes.

💡 Resources

• Bolt: bolt.new and Stackblitz
• One-Shot Podcast: https://aitinkerers.org/podcast
• AI Tinkerers: https://aitinkerers.org