2ro
2e8829ef83
Guard against paying more than the spendable balance at every entry: the Pay tab, the send-flow amount step, and the Review screen all render the amount in red with "You don't have enough grin" and refuse to proceed, so a payment that would only fail later at the node is stopped up front. On Android the phone gives a short error buzz on the blocked tap — new VIBRATE bridge (PlatformCallbacks::vibrate_error -> MainActivity.vibrateError); no-op on desktop. Grim silently clamped the amount and showed nothing. Also enlarge and vertically center the magnifier in the "Send to" search field (an 18px muted label became a 22px centered glyph).
Goblin
Goblin is a private, Cash App-style wallet for GRIN ツ — confidential digital cash on Mimblewimble, with no amounts or addresses on the chain.
Instead of passing slatepack files back and forth, you pay a @username (or an npub) and the payment is delivered for you as an end-to-end encrypted message over nostr and Tor. Relays only ever see ciphertext — never the amount, the sender, or the recipient.
Goblin is a fork of the Grim egui GRIN wallet: it keeps Grim's full GRIN node/wallet engine and layers a Nostr-native, mobile-first payments experience on top.
What it does
- Send to people — pay a
@usernameornpub; the GRIN slatepack travels as a NIP-17 gift-wrapped DM (kind 1059) over Tor and is applied automatically by the recipient's wallet. No files to swap, no need to both be online at once. - In-app identity — a nostr payment key that is deliberately not part of your seed, so you can rotate it any time to stay unlinkable without touching your funds. An optional human-readable
@name(and hosted avatar) comes from the goblin.st identity service. - Private by construction — GRIN's address-less, confidential chain; every relay and HTTP request routed through an embedded arti Tor client (webtunnel bridge by default); keys, names and history stay on your device.
- Configurable amount pairing — show balances against a world currency, Bitcoin, or sats (rates fetched over Tor), or turn the preview off.
- Cross-platform — Linux, macOS, Windows, Android, built in pure Rust on egui.
How a payment travels
you ──slatepack──▶ NIP-17 gift wrap (kind 1059, NIP-44 encrypted)
│
arti / Tor
│
┌─────────────┴─────────────┐
your relays recipient's DM relays (kind 10050)
└─────────────┬─────────────┘
▼
recipient ◀──unwrap, verify seal author, apply slatepack
Both parties only need one relay in common. The default set is the Goblin relay plus large public relays (relay.damus.io, nos.lol), and the set is editable in Settings → Relays.
Build
Desktop (Linux / macOS / Windows)
git submodule update --init --recursive
cargo build --release
./target/release/goblin
Tor's webtunnel bridge is built from Go at compile time — install Go first (e.g. pacman -S go). Without it the bundled bridge is inert and Tor will not bootstrap on networks that block direct Tor connections.
Android
Install the Android SDK / NDK, then from the repo root:
./scripts/android.sh build|release v7|v8|x86
v7/v8/x86 is the device CPU architecture for build; for release pass a version in major.minor.patch form.
Identity service (goblin-nip05d)
The optional @name + avatar service lives in goblin-nip05d/ (axum + SQLite) and is deployed at goblin.st. It implements NIP-05 resolution, NIP-98-authenticated registration/transfer/release, and a hardened avatar pipeline (magic-byte sniffing, bounded decode, full re-encode to a clean 256×256 PNG). The wallet is fully usable — and fully anonymous — without it.
License
Apache License v2.0.
Credits
🤖 Built with AI pair-programming assistance (Claude)
The underlying cross-platform GRIN wallet engine is the upstream Grim project.