How I built RuntimeVault: replay production bugs with full runtime state

Every developer knows this conversation:

"Hey, can you reproduce this bug?"
"No, it works on my machine."
"Can you try again?"
"I already tried 5 times."

I got tired of this loop. So I built RuntimeVault — a tool that captures the entire runtime state when an error fires and lets you replay it locally.

The Problem

Error monitoring tools (Sentry, LogRocket, etc.) show you what happened. But they don't let you reproduce it.

You get a stack trace. Maybe a video. But you still spend hours recreating the environment, guessing which variables were null, which network request failed.

The Solution

RuntimeVault captures everything:

• Stack trace with source-mapped frames
• Variables in scope at throw-time
• Network requests (request/response pairs)
• DOM state
• Cookies, localStorage, sessionStorage
• Environment (browser, OS, URL, feature flags)

Then you run:

bash
rv replay snap_9f2a1c
And your local environment becomes identical to the user's environment at the moment of failure.

How It Works
Install the SDK (2 lines):
import { RuntimeVault } from '@runtimevault/core';
RuntimeVault.init({ apiKey: 'rv_live_xxx' });
Error fires → snapshot captured automatically
Run rv replay → runtime state restored locally
What Makes It Different
Tool    What it captures    Can reproduce locally?
Sentry  Stack trace + breadcrumbs   No
LogRocket   Video of user session   No
RuntimeVault    Complete runtime state  Yes
MCP Integration
The newest feature: AI agents (Claude Code, Cursor, etc.) can read snapshots directly via MCP.

rv-analyze snap_9f2a1c
# Returns: root cause, confidence, suggested fix
The AI doesn't guess from a stack trace — it reads the actual captured state.

Stack
Frontend: Next.js, Tailwind, Framer Motion
Backend: FastAPI, SQLAlchemy, PostgreSQL
Payments: Stripe
Hosting: Railway
Auth: Google/GitHub OAuth + magic links
What's Next
Open source SDK (already live on GitHub)
CLI replay for team workflows
More AI agent integrations
Try It
Free plan forever, no credit card:

runtimevault.dev

GitHub: github.com/giovannesartor/RuntimeVault

Built by @giovanne_sartor