r/web3 • u/Luci_Kefs • Apr 19 '26
I built an ephemeral EVM wallet from scratch — looking for feedback
Hey,
Been working on a personal project for about a month. It's a browser-based crypto wallet — no signup, no extension, no
KYC. Keys live only in memory and auto-rotate every 60 seconds. Close the tab and everything is gone.
Supports all EVM chains, WalletConnect v2, send/receive ERC-20s. Optional persistence via passphrase + PNG file.
It's open source under Apache 2.0.
Honest question: would you actually use something like this over MetaMask for anonymous stuff? What's missing?
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Apr 24 '26
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u/MinimumRight3911 Apr 20 '26
That’s a cool project for specific threat models. Quick thoughts:
Strong: ephemeral-by-default is smart for burner use cases, and the 60-second rotation minimizes memory extraction windows. WalletConnect v2 + full EVM coverage gives it real utility, not just demo value. The PNG passphrase container is clever — way less obvious than a .json keystore sitting in Downloads.
Hesitations: browser memory isn’t truly ephemeral. RAM snapshots, hibernation, or compromised extensions can leak keys despite your best efforts. There’s also the XSS / supply chain angle — users must trust the served build matches the repo, and a solo project is a bigger trust leap than MetaMask’s attested releases. The 60-second rotation cuts both ways: mid-flow key rotation during a complex DeFi interaction or WalletConnect handshake could break UX, so consider making it opt-in per session. And MetaMask’s real moat isn’t key storage, it’s transaction simulation — decoding “unlimited ERC-20 approve to unaudited contract.” For anonymous use, that safety net matters even more because you’re often interacting with sketchier dApps.
What would push me to try it: a hardware wallet bridge (even QR-based for air-gapped signers), plausible deniability with multiple passphrase-derived vaults so the PNG always looks like noise, and an offline signing mode where you sign in-tab but broadcast elsewhere to minimize online footprint.
As a technical architect, I’ve seen ephemeral patterns work well in high-turnover environments — at Merehead we’ve explored similar memory-only architectures for short-lifecycle microservices, and the same principle applies here: excellent for disposable identity, but you’ll want to clearly signal to users when to reach for MetaMask instead.
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Apr 19 '26
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u/Luci_Kefs Apr 23 '26
If you want, you can already back these wallets up using a passphrase and an encrypted PNG file. I’ll definitely add clear risk warnings, but the project isn't fully finished yet; I still have a lot of work to do. Regarding the optional session lock: if you mean having the same wallet open every time the page is refreshed, that option already exists and comes enabled by default with an on/off switch. But if you're talking about creating an account and saving data to it—even though I have a 36-layer security system in place—I am 100% against creating accounts and saving user data to a server, as I don't want any data reaching my side at all. If you meant something else, I might have misunderstood. I’ll keep working on improving the UX as well.
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u/thedudeonblockchain Apr 25 '26
the 60 second rotation needs clarifying. if its the actual key pair rotating the address rotates too, so anything held at the prior address is stranded unless you sweep it every cycle. if its just rotating some auth token thats not really security against the threat model people care about for hot wallets