I Built a Time-Travel Debugger for Solana
Replay lets you paste any Solana mainnet transaction, reconstruct
the exact on-chain state at that slot, and re-execute it locally.
Fork the sandbox, mutate any account field, re-run, and see the diff.
No more guessing from logs. No devnet setup. No shadow environments.
In this video I demo:
→ Replaying a real Jupiter V6 swap with full CPI trace
→ Stepping through every cross-program invocation and CU cost
→ Mutating a Whirlpool fee rate and re-running to see what breaks
→ The side-by-side diff showing exactly what changed
Built with Rust, LiteSVM, Helius, and Next.js.
Available as a web UI, CLI, and TypeScript + Rust SDKs.
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🔗 Links
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Live demo → https://replay-weld.vercel.app
GitHub → https://github.com/zaxcoraider/replay
Docs → https://replay-weld.vercel.app/docs
npm SDK → https://www.npmjs.com/package/@zaxcor...
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⏱ Timestamps
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0:00 — The problem with Solana debugging
0:15 — Paste a real mainnet signature
0:30 — CPI trace tree and account inspector
0:50 — Fork and mutate an account field
1:20 — Re-run and see the diff
1:45 — Wrap up
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#Solana #Web3 #RustLang #DeveloperTools #Blockchain #Colosseum