Replay Builder

AI dev toolsDebuggingVibe codingTime-travel debugging

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Record your app, replay the exact state — debug AI-generated code like it's 2025

WHAT IT SOLVES

Your AI-generated code breaks at runtime. You know the symptom, but figuring out which step actually went wrong? Good luck — the AI won't tell you what it was thinking

WHY IT'S INTERESTING

★ Product taste

Time-travel debugging, but for vibe coding

This isn't another code generator. Replay Builder records your app's state at every step — when something breaks, you literally replay it. bhackett took the classic time-travel debugger concept and dropped it into vibe-coding workflows. The insight: you can trust AI to write code, but you can't trust it to not break things

★ Real craft

Not screenshots — full program state snapshots

Getting 'replay' to actually work — not just 'reproduce' — means serializing full program state with a timeline index. That's not recording a GIF; it's capturing the entire runtime state at every tick and loading it on demand. The hard part is invisible to users, which is exactly how it should be

「The Show HN title says it straight: 'Time travel debugging AI for more reliable vibe coding.' No hedging, no buzzwords — just what it does」
— bhackett