Prepare for public release: generic wording, MIT LICENSE

Make the scaffold standalone and publish-ready:
- Rewrite code + README references to the originating backend as a generic
  "wallet backend" so the service reads as a reusable, run-anywhere LWS.
- Add the MIT LICENSE file (matches Cargo.toml) and a short provenance note.
- Add repository/readme/keywords/categories metadata to Cargo.toml.

Cargo.toml

@@ -5,6 +5,11 @@ edition = "2021"
 rust-version = "1.75"
 description = "Grin light-wallet-server: register a view credential, scan the chain in the background, store recognized outputs in a DB, and serve balance/outputs/broadcast/height."
 license = "MIT"
+repository = "https://github.com/Such-Software/grin-lws"
+readme = "README.md"
+keywords = ["grin", "light-wallet-server", "lws", "mimblewimble", "wallet"]
+categories = ["cryptography::cryptocurrencies"]
+# crates.io publish is gated until the rangeproof-rewind crypto lands (scaffold).
 publish = false
 
 [[bin]]

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Such Software
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -5,9 +5,9 @@ view credential, run a **background scanner** over the Grin chain, **store**
 recognized outputs (with recovered derivation paths) in a **database**, and
 serve balance / unspent-outputs / broadcast / height fast from that store.
 
-It is the Grin analogue of monero-lws, and lets any backend proxy to it exactly
+It is the Grin analogue of monero-lws: a wallet backend proxies to it exactly the
-the way `smirk-backend-core`'s `xmr_wow.rs` proxies to the Monero LWS via
+way a backend proxies to the Monero LWS — forward a view credential, serve the
-`infra/lws/client.rs`.
+stored results back to the wallet.
 
 **Status: SCAFFOLD.** The HTTP surface, DTOs, config, database layer, and the
 scanner loop *structure* are real and build. The two chain-crypto seams — block
@@ -20,12 +20,12 @@ milestone (see [Build order](#build-order)).
 
 ## Why this exists (and why it needs a DB)
 
-`smirk-backend-core`'s current `POST /wallet/grin/scan` is an **on-demand,
+A common wallet-backend approach is an **on-demand, stateless** grin scan: each
-stateless proxy**: each request forwards a `rewind_hash` to grin-wallet's
+request forwards a `rewind_hash` to grin-wallet's `scan_rewind_hash`, which
-`scan_rewind_hash`, which rescans the chain and returns matches, **storing
+rescans the chain and returns matches, **storing nothing**. That works for
-nothing**. That works for Grin's small UTXO set, but it is *not* a
+Grin's small UTXO set, but it is *not* a light-wallet-server — every read
-light-wallet-server — every read re-pays the scan cost, and it has no output
+re-pays the scan cost, and it has no output store to recover derivation paths
-store to recover derivation paths from.
+from.
 
 A real LWS — like monero-lws — keeps a **per-account output store** maintained by
 a **background scanner**, so client reads are O(rows) not O(chain), and it can
@@ -145,33 +145,32 @@ chain_cursor(id=1 PK, height, block_hash)   -- reorg-safe resume
 
 ---
 
-## How `smirk-backend-core` proxies to it
+## How a wallet backend proxies to it
 
-Identical wiring to the XMR/WOW LWS (`infra/lws/client.rs`):
+Identical wiring to a Monero LWS client — forward the view credential, serve the
+stored results:
 
 ```
-wallet ──JWT──▶ smirk-backend-core ──private──▶ grin-lws ──▶ grin node
+wallet ──JWT──▶ wallet backend ──private──▶ grin-lws ──▶ grin node
-  /api/v1/wallet/grin/scan          /get_unspent_outs         (Foreign API v2)
+  /wallet/grin/scan             /get_unspent_outs         (Foreign API v2)
 ```
 
-1. Add `GrinLwsConfig { lws_url, admin_url?, admin_key? }` in `config.rs`, next
+1. Add a grin-lws client config (`lws_url`, optional `admin_url` + `admin_key`)
-   to `LwsConfig`.
+   alongside your existing Monero-LWS config.
-2. Add a `GrinLwsClient` in `infra/` mirroring `infra/lws/client.rs` (shared
+2. Add an HTTP client mirroring your Monero-LWS client (shared `reqwest::Client`,
-   `reqwest::Client`, timeouts, size-capped hostile-response reads, `Secret`-
+   timeouts, size-capped hostile-response reads, a `Secret`-wrapped admin key).
-   wrapped admin key).
+3. Behind a feature flag, have your grin scan endpoint forward the `rewind_hash`
-3. Behind a `features.chains.grin_lws` flag, `POST /wallet/grin/scan` forwards
+   to grin-lws `/get_unspent_outs` (returning outputs **with paths**) instead of
-   the `rewind_hash` to grin-lws `/get_unspent_outs` (returning outputs **with
+   driving grin-wallet `scan_rewind_hash` on-demand.
-   paths**) instead of driving grin-wallet `scan_rewind_hash` on-demand.
 4. Register at balance-fetch time by forwarding `rewind_hash` to grin-lws
-   `/register` (idempotent), exactly as `fetchLwsBalance` awaits `registerLws`
+   `/register` (idempotent), exactly as you await LWS registration for Monero.
-   for XMR/WOW.
 
 **Non-custodial guarantee preserved end to end:** the backend forwards only the
 `rewind_hash` and stores nothing; grin-lws holds the `rewind_hash` for scanning
 just as monero-lws holds the view key. No spend key ever leaves the wallet.
 
-When grin-lws ships, the client can **drop** its `grin_identify_output` helper —
+Once grin-lws is wired in, the wallet client can **drop** any client-side
-`/get_unspent_outs` returns paths directly.
+output-identify helper — `/get_unspent_outs` returns paths directly.
 
 ---
 
@@ -228,3 +227,12 @@ Run as a private service alongside a grin node and its database. Bind to
 loopback / a private network; expose it only to the proxying backend. Add a
 readiness probe on `/ready`. Everything is env-configured — no code changes to
 deploy.
+
+---
+
+## License & provenance
+
+MIT — see [`LICENSE`](LICENSE).
+
+grin-lws was extracted from the [Smirk](https://smirk.cash) wallet's backend and
+generalized into a standalone service that any wallet backend can run.

src/api.rs

@@ -1,10 +1,11 @@
-//! HTTP surface — mirrors the monero-lws user API so smirk-backend-core can
+//! HTTP surface — mirrors the monero-lws user API so a wallet backend can proxy
-//! proxy to it exactly as it proxies the XMR/WOW LWS (see `infra/lws/client.rs`).
+//! to it exactly as it proxies a Monero LWS.
 //!
 //! AUTH: the user API is unauthenticated at THIS layer — grin-lws binds to
-//! loopback / a private network and trusts smirk-backend-core (which does the
+//! loopback / a private network and trusts the proxying wallet backend (which
-//! JWT auth) as its only caller. The admin API (`/list_accounts`, `/rescan`) is
+//! does the JWT auth) as its only caller. The admin API (`/list_accounts`,
-//! gated by a shared bearer (`GRINLWS_ADMIN_KEY`) and disabled when unset.
+//! `/rescan`) is gated by a shared bearer (`GRINLWS_ADMIN_KEY`) and disabled
+//! when unset.
 //!
 //! The `rewind_hash` in every user request is a VIEW credential (public-key
 //! derived — it cannot spend). Its request DTOs omit `Debug` so it is never

src/error.rs

@@ -1,8 +1,7 @@
 //! Error type mapped to HTTP responses.
 //!
-//! Hostile-upstream hygiene (carried over from smirk-backend-core's LWS/grin
+//! Hostile-upstream hygiene: a node/DB error NEVER interpolates an untrusted
-//! clients): a node/DB error NEVER interpolates an untrusted upstream response
+//! upstream response body into the client-facing message.
-//! body into the client-facing message.
 
 use axum::{http::StatusCode, response::IntoResponse, Json};
 

src/grin.rs

@@ -4,9 +4,8 @@
 //! block outputs (commit + rangeproof), and relay a finalized transaction. This
 //! is the ONLY component that reaches the chain; everything else reads the DB.
 //!
-//! Hostile-upstream hygiene (carried from smirk-backend-core's node client):
+//! Hostile-upstream hygiene: per-request + connect timeouts, a streaming
-//! per-request + connect timeouts, a streaming body-size cap, and errors that
+//! body-size cap, and errors that never interpolate an untrusted node body.
-//! never interpolate an untrusted node body.
 //!
 //! REWIND (the hard, deferred part): recognizing which of a block's outputs
 //! belong to a registered account means rewinding each output's Bulletproof

src/main.rs

@@ -10,25 +10,24 @@
 //!
 //! WHY A DB
 //! --------
-//! smirk-backend-core's current `POST /wallet/grin/scan` is an ON-DEMAND,
+//! A typical wallet backend exposes an ON-DEMAND, STATELESS grin scan: each
-//! STATELESS proxy: each request forwards a `rewind_hash` to grin-wallet's
+//! request forwards a `rewind_hash` to grin-wallet's `scan_rewind_hash`, which
-//! `scan_rewind_hash`, which rescans and returns matches, storing NOTHING. That
+//! rescans and returns matches, storing NOTHING. That is fine for grin's small
-//! is fine for grin's small UTXO set but it is NOT a light-wallet-server. A real
+//! UTXO set but it is NOT a light-wallet-server. A real LWS — like monero-lws —
-//! LWS — like monero-lws — keeps a per-account output store maintained by a
+//! keeps a per-account output store maintained by a background scanner, so reads
-//! background scanner, so reads are O(rows) not O(chain). Hence this service
+//! are O(rows) not O(chain). Hence this service needs a database (the 3 tables in
-//! needs a database (the 3 tables in `migrations/`).
+//! `migrations/`).
 //!
-//! HOW smirk-backend-core PROXIES TO IT
+//! HOW A WALLET BACKEND PROXIES TO IT
-//! ------------------------------------
+//! ----------------------------------
-//! Identical wiring to the XMR/WOW LWS (`infra/lws/client.rs`): the backend adds
+//! Identical wiring to a Monero LWS client: the backend adds a grin-lws client
-//! a `GrinLwsConfig { lws_url, admin_url?, admin_key? }` and a `GrinLwsClient`;
+//! (`lws_url`, optional `admin_url` + `admin_key`); behind a feature flag, its
-//! when the `grin_lws` feature is on, `POST /wallet/grin/scan` forwards the
+//! grin scan endpoint forwards the `rewind_hash` to this service's
-//! `rewind_hash` to this service's `/get_unspent_outs` (and registers via
+//! `/get_unspent_outs` (and registers via `/register` at balance-fetch time,
-//! `/register` at balance-fetch time, idempotently, exactly as `fetchLwsBalance`
+//! idempotently, exactly as it awaits LWS registration for Monero). Non-custodial
-//! awaits `registerLws` for XMR/WOW). Non-custodial guarantee preserved: the
+//! guarantee preserved: the backend forwards only the `rewind_hash` and stores
-//! backend forwards only the `rewind_hash` and stores nothing; grin-lws holds
+//! nothing; grin-lws holds the `rewind_hash` for scanning just as monero-lws
-//! the `rewind_hash` for scanning just as monero-lws holds the view key. NEVER a
+//! holds the view key. NEVER a spend key.
-//! spend key.
 //!
 //! STATUS: SCAFFOLD. Routes, DTOs, config, DB layer, and the scanner loop
 //! structure are real; the two chain-crypto seams — block parsing

src/secret.rs

@@ -1,5 +1,5 @@
 //! A tiny redacting wrapper so secrets (DB URL, node auth, admin key) never leak
-//! into `Debug` output or tracing spans. Mirrors smirk-backend-core's `Secret`.
+//! into `Debug` output or tracing spans.
 
 #[derive(Clone)]
 pub struct Secret(String);