config: GP_CHECKOUT_METHODS to pick which checkout methods show

Operators can now choose which payment methods the hosted /pay page
offers: GP_CHECKOUT_METHODS=nostr, =slatepack, or nostr,slatepack
(unset = both, current behavior). Gates the two checkout sections
independently; slatepack still also requires a loaded wallet. The Nostr
ingest service (GP_INGEST) and the /invoice JSON API are unchanged.

README.md

@@ -17,9 +17,21 @@ carries the full merchant surface:
   invoice automatically.
 - **Hosted checkout:** a zero-JS `/pay/<token>` page (server-rendered
   Askama + one CSS file + a server-generated QR SVG at ECC level H with an
-  optional Goblin-mark center logo), live status via `<meta http-equiv=refresh>`,
+  optional GoblinPay-mark center logo) with live status via
-  and a manual slatepack fallback (paste S1 -> offline `receive_tx` -> copy the
+  `<meta http-equiv=refresh>`. It offers two first-class ways to pay:
-  S2 back) on every page. The same renderer serves embedded and hosted use.
+  - **Goblin Wallet (Nostr):** scan the `nprofile` QR (or copy it) and the
+    payment auto-receives over Nostr.
+  - **Slatepack (`grin1`):** pay from any Grin wallet, no Nostr needed. The
+    page shows the wallet's stable index-0 Slatepack address (`grin1...`) plus
+    its QR and the exact amount to send. The payer sends that amount to the
+    address using their wallet's Slatepack/file method, pastes the resulting S1
+    into the page (offline `receive_tx`), then copies the returned S2 back into
+    their wallet to finalize and broadcast it. There is no Tor listener; the
+    `grin1` address is stable and reused across invoices, and the existing
+    invoice matcher and on-chain confirmation handle the received payment like
+    any other. The Slatepack option only appears when a wallet is loaded.
+
+  The same renderer serves embedded and hosted use.
 - **Per-user endpubs:** an admin assigns one receiving identity per user
   (a derived child keyed by `(user_id, epoch)`; only public keys and the
   rotation clock are stored, never private keys), with optional rolling rotation
@@ -65,6 +77,7 @@ Everything is environment variables, defaults are safe for local use.
 | `GP_RELAYS` | unset | Comma-separated relay URLs |
 | `GP_NYM` | `on` | Route Nostr traffic over the Nym mixnet (`on` or `off`) |
 | `GP_INGEST` | `on` | Nostr ingest service (`off` = HTTP surface only, for debugging) |
+| `GP_CHECKOUT_METHODS` | `nostr,slatepack` | Which payment methods the hosted `/pay/<token>` page shows: comma list of `nostr` (Goblin Wallet) and `slatepack` (`grin1`). Unset = both. Unknown tokens are ignored; an empty result falls back to both |
 | `GP_MATCH_MODE` | `memo` | Default matching mode: `memo`, `derived`, `amount` |
 | `GP_MNEMONIC` | unset | Grin seed mnemonic (money secret) |
 | `GP_WALLET_PASSWORD` | unset | Password encrypting the wallet seed and the Nostr identity at rest |
@@ -75,7 +88,7 @@ Everything is environment variables, defaults are safe for local use.
 | `GP_ADMIN_TOKEN` | unset | Bearer token for the admin dashboard + endpub/webhook API |
 | `GP_WEBHOOK_URL` | unset | Webhook endpoint for payment events (requires `GP_WEBHOOK_SECRET`) |
 | `GP_WEBHOOK_SECRET` | unset | HMAC-SHA256 secret for signing webhooks |
-| `GP_QR_LOGO` | Goblin mark | Checkout QR center logo: unset = Goblin mark, `off`/`none` = plain, else a URL/path |
+| `GP_QR_LOGO` | GoblinPay mark | Checkout QR center logo: unset = GoblinPay mark, `off`/`none` = plain, else a URL/path |
 | `GP_MERCHANT_NPUB` | unset | Merchant npub for the NIP-17 confirmed-payment DM |
 | `GP_NOTIFY_MERCHANT_DM` | `off` | Send a NIP-17 DM to the merchant on a received payment |
 | `GP_NOTIFY_PAYER_RECEIPT` | `off` | Send a NIP-17 receipt DM to the payer |
@@ -87,6 +100,19 @@ Everything is environment variables, defaults are safe for local use.
 | `GP_QUOTE_TTL` | `900` | Seconds a created fiat invoice locks its Grin quote (its expiry window) |
 | `GP_RATE_STALE_MAX` | `0` | Bounded stale-rate fallback in seconds if a live fetch fails (0 = off) |
 
+### Checkout methods
+
+`GP_CHECKOUT_METHODS` only controls what the hosted `/pay/<token>` page
+advertises to a payer; it does not turn any payment processing on or off. The
+Slatepack (`grin1`) method also needs a loaded wallet to appear, so an enabled
+method that cannot work is simply hidden. Keep this consistent with `GP_INGEST`:
+`GP_INGEST` runs the Nostr ingest service that actually receives and matches
+Goblin Wallet payments, so `GP_INGEST=off` with `GP_CHECKOUT_METHODS=nostr`
+would advertise a Nostr method that nothing is listening for. If you disable
+ingest, drop `nostr` from `GP_CHECKOUT_METHODS`; if you advertise `nostr`, keep
+ingest on. The connector `POST /invoice` JSON response still returns the
+`nprofile` regardless of this setting, which affects only the hosted page.
+
 ### Conversion rates (optional)
 
 A store that prices in fiat (for example cryptodrip.com prices in USD) sends

crates/gp-core/src/config.rs

@@ -136,6 +136,15 @@ pub struct Config {
     /// Run the Nostr ingest service (`GP_INGEST`: `on` or `off`, default on).
     /// When on, the wallet and identity secrets are required at boot.
     pub ingest: bool,
+    /// Show the Nostr (Goblin Wallet, `nprofile`) method on the hosted checkout
+    /// page. Part of `GP_CHECKOUT_METHODS` (comma list of `nostr`/`slatepack`;
+    /// unset = both). This gates only the hosted PAGE display, not the connector
+    /// API or the ingest service.
+    pub checkout_nostr: bool,
+    /// Show the Slatepack (`grin1`) method on the hosted checkout page. Part of
+    /// `GP_CHECKOUT_METHODS`. Still requires a loaded wallet to actually appear:
+    /// an enabled method that cannot work is simply hidden.
+    pub checkout_slatepack: bool,
     /// Global default matching mode (`GP_MATCH_MODE`).
     pub match_mode: MatchMode,
     /// Grin seed mnemonic (`GP_MNEMONIC` or `GP_MNEMONIC_FILE`). Money secret.
@@ -171,7 +180,7 @@ pub struct Config {
     #[serde(skip)]
     pub webhook_secret: Option<Secret>,
     /// Center-logo source for checkout QR codes (`GP_QR_LOGO`): unset = the
-    /// bundled Goblin mark, `off`/`none` = no logo, else a URL or static path.
+    /// bundled GoblinPay mark, `off`/`none` = no logo, else a URL or static path.
     pub qr_logo: Option<String>,
     /// Merchant npub for confirmed-payment DMs (`GP_MERCHANT_NPUB`).
     pub merchant_npub: Option<String>,
@@ -213,7 +222,7 @@ pub const DEFAULT_RATE_CACHE_TTL: i64 = 60;
 pub const DEFAULT_QUOTE_TTL: i64 = 900;
 
 /// Default center-logo path served by gp-server when `GP_QR_LOGO` is unset.
-pub const DEFAULT_QR_LOGO: &str = "/static/goblin-mark.svg";
+pub const DEFAULT_QR_LOGO: &str = "/static/goblinpay-mark.svg";
 
 impl Default for Config {
     fn default() -> Self {
@@ -228,6 +237,8 @@ impl Default for Config {
             relays: Vec::new(),
             nym: true,
             ingest: true,
+            checkout_nostr: true,
+            checkout_slatepack: true,
             match_mode: MatchMode::Memo,
             mnemonic: None,
             wallet_password: None,
@@ -322,6 +333,9 @@ impl Config {
             other => return Err(format!("GP_INGEST must be `on` or `off` (got `{other}`)")),
         };
 
+        let (checkout_nostr, checkout_slatepack) =
+            parse_checkout_methods(get("GP_CHECKOUT_METHODS"));
+
         let match_mode = match get("GP_MATCH_MODE").as_deref().unwrap_or("memo") {
             "memo" => MatchMode::Memo,
             "derived" => MatchMode::Derived,
@@ -394,6 +408,8 @@ impl Config {
             relays,
             nym,
             ingest,
+            checkout_nostr,
+            checkout_slatepack,
             match_mode,
             mnemonic,
             wallet_password,
@@ -425,6 +441,18 @@ impl Config {
         self.qr_logo.as_deref()
     }
 
+    /// The enabled checkout methods as a stable comma list, for the startup log.
+    fn checkout_methods_str(&self) -> String {
+        let mut methods = Vec::new();
+        if self.checkout_nostr {
+            methods.push("nostr");
+        }
+        if self.checkout_slatepack {
+            methods.push("slatepack");
+        }
+        methods.join(",")
+    }
+
     /// Fail-fast consistency checks.
     fn validate(&self) -> Result<(), String> {
         if self.bind.is_empty() {
@@ -479,7 +507,8 @@ impl Config {
         let set = |o: bool| if o { "set" } else { "unset" };
         format!(
             "bind={} tls={} db={} data_dir={} node={} chain={:?} relay_mode={:?} \
-             relays={:?} nym={} ingest={} match_mode={:?} mnemonic={} wallet_password={} \
+             relays={:?} nym={} ingest={} checkout_methods={} match_mode={:?} mnemonic={} \
+             wallet_password={} \
              nsec={} ncryptsec={} public_url={} api_token={} admin_token={} webhook_url={} \
              webhook_secret={} qr_logo={} merchant_npub={} notify_merchant_dm={} \
              notify_payer_receipt={} endpub_rotate_interval={} endpub_overlap_epochs={} \
@@ -498,6 +527,7 @@ impl Config {
             self.relays,
             if self.nym { "on" } else { "off" },
             if self.ingest { "on" } else { "off" },
+            self.checkout_methods_str(),
             self.match_mode,
             set(self.mnemonic.is_some()),
             set(self.wallet_password.is_some()),
@@ -527,6 +557,35 @@ impl Config {
     }
 }
 
+/// Parse `GP_CHECKOUT_METHODS` (comma list of `nostr`/`slatepack`) into the two
+/// display flags. Parsing is lenient: tokens are trimmed, lowercased, and
+/// unknown tokens are ignored with a warning. Unset (`None`) enables both, which
+/// preserves the historical default of showing every available method. If a set
+/// value parses to no known methods, both are enabled (a checkout must offer at
+/// least one way to pay) and a warning is logged.
+fn parse_checkout_methods(raw: Option<String>) -> (bool, bool) {
+    let Some(raw) = raw else {
+        return (true, true);
+    };
+    let mut nostr = false;
+    let mut slatepack = false;
+    for tok in raw.split(',') {
+        match tok.trim().to_lowercase().as_str() {
+            "" => {}
+            "nostr" => nostr = true,
+            "slatepack" => slatepack = true,
+            other => log::warn!("GP_CHECKOUT_METHODS: ignoring unknown method `{other}`"),
+        }
+    }
+    if !nostr && !slatepack {
+        log::warn!(
+            "GP_CHECKOUT_METHODS enabled no known methods; defaulting to both (nostr,slatepack)"
+        );
+        return (true, true);
+    }
+    (nostr, slatepack)
+}
+
 /// Parse an `on`/`off` flag with a default.
 fn parse_bool(
     get: &dyn Fn(&str) -> Option<String>,
@@ -637,6 +696,36 @@ mod tests {
         assert_eq!(cfg.match_mode, MatchMode::Derived);
     }
 
+    #[test]
+    fn checkout_methods_default_and_parsing() {
+        // Unset: both methods on (unchanged historical behavior).
+        let cfg = load(&[]).unwrap();
+        assert!(cfg.checkout_nostr);
+        assert!(cfg.checkout_slatepack);
+
+        // Single method selects only that method.
+        let cfg = load(&[("GP_CHECKOUT_METHODS", "nostr")]).unwrap();
+        assert!(cfg.checkout_nostr);
+        assert!(!cfg.checkout_slatepack);
+
+        let cfg = load(&[("GP_CHECKOUT_METHODS", "slatepack")]).unwrap();
+        assert!(!cfg.checkout_nostr);
+        assert!(cfg.checkout_slatepack);
+
+        // Both, order/whitespace/case insensitive, unknown tokens ignored.
+        let cfg = load(&[("GP_CHECKOUT_METHODS", " Slatepack , NOSTR ,bogus,")]).unwrap();
+        assert!(cfg.checkout_nostr);
+        assert!(cfg.checkout_slatepack);
+
+        // Empty or all-garbage parses to no methods -> defaults to both.
+        let cfg = load(&[("GP_CHECKOUT_METHODS", "")]).unwrap();
+        assert!(cfg.checkout_nostr);
+        assert!(cfg.checkout_slatepack);
+        let cfg = load(&[("GP_CHECKOUT_METHODS", "lightning, bitcoin")]).unwrap();
+        assert!(cfg.checkout_nostr);
+        assert!(cfg.checkout_slatepack);
+    }
+
     #[test]
     fn tls_rustls_requires_cert_and_key() {
         assert!(load(&[("GP_TLS", "rustls")]).is_err());

crates/gp-server/src/checkout.rs

@@ -1,13 +1,15 @@
 //! The hosted, zero-JS checkout: the `/pay/<token>` page (shared renderer for
-//! embedded and hosted use), its live status, and the manual-slatepack
+//! embedded and hosted use), its live status, and the Slatepack receive flow.
-//! fallback.
 //!
-//! The page shows the amount, a server-generated QR SVG of the recipient
+//! The page offers two first-class ways to pay: the Goblin/Nostr path (a QR
-//! `nprofile`, the `nprofile`/`npub` strings, live status via a
+//! SVG of the recipient `nprofile` plus the `nprofile`/`npub` strings) and a
-//! `<meta http-equiv="refresh">` while open, and a `<textarea>` POST form to
+//! Slatepack (`grin1`) path for any Grin wallet (the wallet's stable index-0
-//! paste an S1 slatepack when the automatic Nostr flow cannot be used. On
+//! Slatepack address, its QR, and a `<textarea>` POST form to paste the S1 the
-//! submit, the same offline `receive_tx` runs and the S2 reply renders back for
+//! payer's wallet produces). It also shows the amount and live status via a
-//! the payer to copy and finalize. No JavaScript anywhere.
+//! `<meta http-equiv="refresh">` while open. On submit, the same offline
+//! `receive_tx` runs and the S2 reply renders back for the payer to finalize
+//! and broadcast. The Slatepack path only appears when a wallet is loaded. No
+//! JavaScript anywhere.
 
 use actix_web::{web, HttpResponse, Responder};
 use askama::Template;
@@ -32,6 +34,12 @@ pub struct CheckoutInfo {
     pub npub: String,
     pub nprofile: String,
     pub qr_svg: String,
+    /// The wallet's stable `grin1` Slatepack address, when a wallet is loaded.
+    /// `None` (and no Slatepack option shown) when the instance runs with no
+    /// wallet, mirroring how the manual receive handler degrades.
+    pub slatepack_address: Option<String>,
+    /// QR SVG of the `grin1` Slatepack address (present with the address).
+    pub slatepack_qr_svg: Option<String>,
     pub amount_display: String,
     pub status: String,
     pub memo: Option<String>,
@@ -41,14 +49,50 @@ pub struct CheckoutInfo {
 /// Build the presentation for an invoice: the nprofile, its QR, the pay URL,
 /// and a human amount. Shared by the hosted page and the connector API so both
 /// render identically.
-pub fn build_info(inv: &Invoice, cfg: &Config) -> CheckoutInfo {
+///
+/// `slatepack_addr` is the wallet's stable `grin1` Slatepack address when a
+/// wallet is loaded (the hosted page passes it so a payer can pay from any Grin
+/// wallet without Nostr); pass `None` when no wallet is available or the
+/// caller does not surface the Slatepack option (e.g. the JSON connector API),
+/// in which case no Slatepack address or QR is produced.
+pub fn build_info(inv: &Invoice, cfg: &Config, slatepack_addr: Option<&str>) -> CheckoutInfo {
     let relays = gp_nostr::relays::resolve(&cfg.relays);
     let recipient_pubkey = inv.recipient_pubkey.clone().unwrap_or_default();
-    let (npub, nprofile) = match PublicKey::from_hex(&recipient_pubkey) {
+    // The Nostr (Goblin Wallet) method is only surfaced when the operator has it
-        Ok(pk) => (gp_nostr::npub_of(pk), gp_nostr::nprofile(pk, &relays)),
+    // enabled (`GP_CHECKOUT_METHODS`). Disabled, the nprofile/npub/QR are left
-        Err(_) => (String::new(), String::new()),
+    // empty and the template omits the whole section. This gates only the hosted
+    // PAGE display; the connector API and ingest are unaffected.
+    let (npub, nprofile) = if cfg.checkout_nostr {
+        match PublicKey::from_hex(&recipient_pubkey) {
+            Ok(pk) => (gp_nostr::npub_of(pk), gp_nostr::nprofile(pk, &relays)),
+            Err(_) => (String::new(), String::new()),
+        }
+    } else {
+        (String::new(), String::new())
+    };
+    // The QR carries a pay-URI so a scanning wallet can auto-fill the amount
+    // (and memo). The human-readable nprofile/npub strings on the page are
+    // unchanged — only the QR payload gains the query. An invalid pubkey yields
+    // an empty nprofile; keep that empty (no useless `nostr:` QR).
+    let qr_payload = if nprofile.is_empty() {
+        nprofile.clone()
+    } else {
+        pay_uri(&nprofile, inv)
+    };
+    let qr_svg = qr::svg(&qr_payload, cfg.qr_logo_href()).unwrap_or_default();
+    // The Slatepack (grin1) address is stable and reused across invoices; its
+    // QR carries the bare address (a Grin wallet reads no amount from it, so
+    // the page states the amount to send in text next to it). No address means
+    // no wallet loaded: the page simply omits the Slatepack option.
+    // The Slatepack method needs both operator opt-in (`GP_CHECKOUT_METHODS`)
+    // and a loaded wallet: an enabled method that cannot work is simply hidden.
+    let (slatepack_address, slatepack_qr_svg) = match slatepack_addr {
+        Some(addr) if cfg.checkout_slatepack && !addr.is_empty() => {
+            let qr = qr::svg(addr, cfg.qr_logo_href()).unwrap_or_default();
+            (Some(addr.to_string()), Some(qr))
+        }
+        _ => (None, None),
     };
-    let qr_svg = qr::svg(&nprofile, cfg.qr_logo_href()).unwrap_or_default();
     let amount_display = amount_display(inv);
     let token = inv.token.clone().unwrap_or_default();
     CheckoutInfo {
@@ -59,6 +103,8 @@ pub fn build_info(inv: &Invoice, cfg: &Config) -> CheckoutInfo {
         npub,
         nprofile,
         qr_svg,
+        slatepack_address,
+        slatepack_qr_svg,
         amount_display,
         status: inv.status.clone(),
         memo: inv.memo.clone(),
@@ -86,6 +132,53 @@ fn amount_display(inv: &Invoice) -> String {
     }
 }
 
+/// Build the QR pay-URI for an invoice: `nostr:<nprofile>`, plus `?amount=`
+/// when the invoice has an exact expected amount, plus `&memo=` when it carries
+/// a human memo. A scanning Goblin wallet auto-fills the amount (and note) from
+/// this; open-amount invoices stay a bare `nostr:<nprofile>`.
+///
+/// The URI never carries the invoice token or any key — only the already-public
+/// recipient nprofile, relay hints, the amount, and the human memo shown on the
+/// page. `expected_amount` is a locked nanogrin quote (i64 in the DB, always
+/// non-negative here); only strictly positive amounts are emitted.
+fn pay_uri(nprofile: &str, inv: &Invoice) -> String {
+    let mut uri = format!("nostr:{nprofile}");
+    let mut sep = '?';
+    if let Some(nano) = inv.expected_amount {
+        if nano > 0 {
+            uri.push(sep);
+            uri.push_str("amount=");
+            uri.push_str(&nanogrin_to_grin(nano as u64));
+            sep = '&';
+        }
+    }
+    if let Some(memo) = inv.memo.as_deref() {
+        let memo = memo.trim();
+        if !memo.is_empty() {
+            uri.push(sep);
+            uri.push_str("memo=");
+            uri.push_str(&percent_encode(memo));
+        }
+    }
+    uri
+}
+
+/// Minimal RFC-3986 percent-encoding for a query value: keep the unreserved set
+/// (`A-Z a-z 0-9 - . _ ~`), percent-escape every other byte. Small and
+/// dependency-free (gp-core has no percent-encoding crate).
+fn percent_encode(s: &str) -> String {
+    let mut out = String::with_capacity(s.len());
+    for &b in s.as_bytes() {
+        match b {
+            b'A'..=b'Z' | b'a'..=b'z' | b'0'..=b'9' | b'-' | b'.' | b'_' | b'~' => {
+                out.push(b as char)
+            }
+            _ => out.push_str(&format!("%{b:02X}")),
+        }
+    }
+    out
+}
+
 /// The checkout page template.
 #[derive(Template)]
 #[template(path = "pay.html")]
@@ -94,7 +187,6 @@ struct PayPage {
     is_open: bool,
     is_paid: bool,
     is_expired: bool,
-    wallet_available: bool,
 }
 
 /// The manual-slatepack result template (S2 to copy back).
@@ -131,12 +223,18 @@ async fn pay_page(
         }
     };
     let status = inv.status();
+    // Surface the wallet's stable grin1 Slatepack address (same wallet handle
+    // the manual receive uses). No wallet loaded, or the address cannot be
+    // derived, means no Slatepack option is shown.
+    let slatepack_addr = wallet
+        .get_ref()
+        .as_ref()
+        .and_then(|w| w.slatepack_address().ok());
     let page = PayPage {
-        info: build_info(&inv, cfg.get_ref()),
+        info: build_info(&inv, cfg.get_ref(), slatepack_addr.as_deref()),
         is_open: status == InvoiceStatus::Open,
         is_paid: status == InvoiceStatus::Paid,
         is_expired: status == InvoiceStatus::Expired,
-        wallet_available: wallet.get_ref().is_some(),
     };
     render(page)
 }
@@ -243,3 +341,184 @@ fn render<T: Template>(page: T) -> HttpResponse {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// A minimal invoice fixture: only the fields the QR pay-URI reads matter.
+    fn invoice(expected_amount: Option<i64>, memo: Option<&str>) -> Invoice {
+        Invoice {
+            id: "inv_1".into(),
+            order_ref: None,
+            expected_amount,
+            expiry: None,
+            status: "open".into(),
+            created_at: "2026-01-01T00:00:00Z".into(),
+            token: Some("secret-token-should-never-leak".into()),
+            memo: memo.map(str::to_string),
+            recipient_pubkey: Some("aa".repeat(32)),
+            fiat_amount: None,
+            fiat_currency: None,
+            match_mode: None,
+            paid_payment_id: None,
+            paid_at: None,
+            quote_rate: None,
+            quote_source: None,
+        }
+    }
+
+    #[test]
+    fn build_info_surfaces_slatepack_address_when_wallet_loaded() {
+        // A loaded wallet passes its grin1 address: build_info exposes it plus
+        // a QR for it, so the hosted page can show the Slatepack option.
+        let inv = invoice(Some(1_500_000_000), None);
+        let cfg = Config::default();
+        let info = build_info(&inv, &cfg, Some("grin1qtestaddress"));
+        assert_eq!(info.slatepack_address.as_deref(), Some("grin1qtestaddress"));
+        let qr = info.slatepack_qr_svg.expect("slatepack QR present");
+        assert!(qr.contains("<svg"), "grin1 QR is an SVG");
+    }
+
+    #[test]
+    fn build_info_omits_slatepack_when_no_wallet() {
+        // No wallet (None) or a blank address: no Slatepack address or QR, so
+        // the page simply does not show the Slatepack option.
+        let inv = invoice(Some(1_500_000_000), None);
+        let cfg = Config::default();
+        let info = build_info(&inv, &cfg, None);
+        assert!(info.slatepack_address.is_none());
+        assert!(info.slatepack_qr_svg.is_none());
+        let blank = build_info(&inv, &cfg, Some(""));
+        assert!(blank.slatepack_address.is_none());
+        assert!(blank.slatepack_qr_svg.is_none());
+    }
+
+    #[test]
+    fn checkout_nostr_disabled_hides_nostr_section() {
+        // GP_CHECKOUT_METHODS=slatepack: the Nostr method is off, so build_info
+        // leaves the nprofile/npub empty and the page omits the Nostr section
+        // while still showing the Slatepack one.
+        let inv = invoice(Some(1_500_000_000), None);
+        let mut cfg = Config::default();
+        cfg.checkout_nostr = false;
+        cfg.checkout_slatepack = true;
+        let info = build_info(&inv, &cfg, Some("grin1qtestaddress"));
+        assert!(info.nprofile.is_empty(), "nprofile empty when nostr off");
+        assert!(info.npub.is_empty(), "npub empty when nostr off");
+        assert_eq!(info.slatepack_address.as_deref(), Some("grin1qtestaddress"));
+
+        let page = PayPage {
+            info,
+            is_open: true,
+            is_paid: false,
+            is_expired: false,
+        };
+        let html = page.render().unwrap();
+        assert!(
+            !html.contains("Pay with Goblin Wallet"),
+            "Nostr section absent when checkout_nostr=false"
+        );
+        assert!(
+            html.contains("Pay by Slatepack"),
+            "Slatepack section still present"
+        );
+    }
+
+    #[test]
+    fn checkout_slatepack_disabled_hides_slatepack_section() {
+        // GP_CHECKOUT_METHODS=nostr: the Slatepack method is off, so even with a
+        // wallet address available, build_info drops it and the page omits the
+        // Slatepack section while still showing the Nostr one.
+        let inv = invoice(Some(1_500_000_000), None);
+        let mut cfg = Config::default();
+        cfg.checkout_nostr = true;
+        cfg.checkout_slatepack = false;
+        let info = build_info(&inv, &cfg, Some("grin1qtestaddress"));
+        assert!(
+            info.slatepack_address.is_none(),
+            "slatepack dropped when method off"
+        );
+        assert!(info.slatepack_qr_svg.is_none());
+        assert!(!info.nprofile.is_empty(), "nprofile present when nostr on");
+
+        let page = PayPage {
+            info,
+            is_open: true,
+            is_paid: false,
+            is_expired: false,
+        };
+        let html = page.render().unwrap();
+        assert!(
+            html.contains("Pay with Goblin Wallet"),
+            "Nostr section present"
+        );
+        assert!(
+            !html.contains("Pay by Slatepack"),
+            "Slatepack section absent when checkout_slatepack=false"
+        );
+    }
+
+    #[test]
+    fn amount_invoice_encodes_amount() {
+        // 1.5 GRIN → nostr:<nprofile>?amount=1.5
+        let inv = invoice(Some(1_500_000_000), None);
+        assert_eq!(
+            pay_uri("nprofile1abc", &inv),
+            "nostr:nprofile1abc?amount=1.5"
+        );
+    }
+
+    #[test]
+    fn open_amount_invoice_stays_bare() {
+        // Open amount (no expected_amount, no memo) → bare nostr:<nprofile>.
+        let inv = invoice(None, None);
+        assert_eq!(pay_uri("nprofile1abc", &inv), "nostr:nprofile1abc");
+    }
+
+    #[test]
+    fn amount_and_memo_encoded() {
+        let inv = invoice(Some(1_000_000_000), Some("Coffee & cake"));
+        assert_eq!(
+            pay_uri("nprofile1abc", &inv),
+            "nostr:nprofile1abc?amount=1&memo=Coffee%20%26%20cake"
+        );
+    }
+
+    #[test]
+    fn memo_only_uses_question_mark() {
+        // No amount but a memo → the memo is the first (and only) query param.
+        let inv = invoice(None, Some("hi"));
+        assert_eq!(pay_uri("nprofile1abc", &inv), "nostr:nprofile1abc?memo=hi");
+    }
+
+    #[test]
+    fn zero_and_blank_are_treated_as_open() {
+        assert_eq!(
+            pay_uri("nprofile1abc", &invoice(Some(0), None)),
+            "nostr:nprofile1abc"
+        );
+        // A whitespace-only memo is dropped.
+        assert_eq!(
+            pay_uri("nprofile1abc", &invoice(None, Some("   "))),
+            "nostr:nprofile1abc"
+        );
+    }
+
+    #[test]
+    fn uri_never_leaks_token_or_key() {
+        // The token and recipient private material must never appear in the QR.
+        let inv = invoice(Some(2_000_000_000), Some("order 42"));
+        let uri = pay_uri("nprofile1abc", &inv);
+        assert!(!uri.contains("secret-token-should-never-leak"));
+        assert!(!uri.contains("token"));
+    }
+
+    #[test]
+    fn percent_encode_covers_reserved_and_unicode() {
+        assert_eq!(percent_encode("a-b_c.d~e"), "a-b_c.d~e");
+        assert_eq!(percent_encode("a b&c=d"), "a%20b%26c%3Dd");
+        // Multi-byte UTF-8 is percent-encoded byte-by-byte.
+        assert_eq!(percent_encode("é"), "%C3%A9");
+    }
+}

crates/gp-server/src/invoices.rs

@@ -145,7 +145,9 @@ async fn create_invoice(
                 .json(serde_json::json!({"error": "internal error"}));
         }
     };
-    let info = build_info(&inv, cfg.get_ref());
+    // The JSON connector API surfaces the Nostr checkout fields only; the
+    // grin1 Slatepack option is presented on the hosted /pay page.
+    let info = build_info(&inv, cfg.get_ref(), None);
     HttpResponse::Ok().json(checkout_json(&info))
 }
 
@@ -161,7 +163,7 @@ async fn get_invoice(
     }
     match invoice::get(pool.get_ref(), &path.into_inner()).await {
         Ok(Some(inv)) => {
-            let info = build_info(&inv, cfg.get_ref());
+            let info = build_info(&inv, cfg.get_ref(), None);
             HttpResponse::Ok().json(checkout_json(&info))
         }
         Ok(None) => HttpResponse::NotFound().json(serde_json::json!({"error": "not found"})),

crates/gp-server/src/main.rs

@@ -44,19 +44,40 @@ async fn style() -> impl Responder {
         .body(include_str!("../../../static/style.css"))
 }
 
-/// The bundled Goblin mark, the default QR center logo.
+/// The bundled Goblin mark (legacy default QR center logo; still served so an
+/// operator can keep `GP_QR_LOGO=/static/goblin-mark.svg`).
 async fn goblin_mark() -> impl Responder {
     HttpResponse::Ok()
         .content_type("image/svg+xml")
         .body(include_str!("../../../static/goblin-mark.svg"))
 }
 
+/// The GoblinPay mark, the default QR center logo (dark "P" on the brand gold,
+/// sized for contrast on the QR's white backing).
+async fn goblinpay_mark() -> impl Responder {
+    HttpResponse::Ok()
+        .content_type("image/svg+xml")
+        .body(include_str!("../../../static/goblinpay-mark.svg"))
+}
+
+/// The GoblinPay wordmark (white), shown as the checkout page header logo.
+async fn goblinpay_wordmark() -> impl Responder {
+    HttpResponse::Ok()
+        .content_type("image/svg+xml")
+        .body(include_str!("../../../static/goblinpay-wordmark.svg"))
+}
+
 /// Route table, shared by `main` and the tests.
 fn routes(cfg: &mut web::ServiceConfig) {
     cfg.route("/", web::get().to(index))
         .route("/health", web::get().to(health))
         .route("/static/style.css", web::get().to(style))
-        .route("/static/goblin-mark.svg", web::get().to(goblin_mark));
+        .route("/static/goblin-mark.svg", web::get().to(goblin_mark))
+        .route("/static/goblinpay-mark.svg", web::get().to(goblinpay_mark))
+        .route(
+            "/static/goblinpay-wordmark.svg",
+            web::get().to(goblinpay_wordmark),
+        );
     // Payment status + signed-receipt reads (public-by-token, M4).
     payments::configure(cfg);
     // Hosted checkout + manual slatepack (public-by-token, M5).

crates/gp-server/tests/checkout_e2e.rs

@@ -164,6 +164,10 @@ async fn pay_page_renders_zero_js_with_qr_and_nprofile() {
     assert!(html.contains("1.5 GRIN"), "amount shown");
     assert!(html.contains("<svg"), "server-rendered QR present");
     assert!(html.contains("nprofile1"), "nprofile string present");
+    assert!(
+        !html.contains("Pay by Slatepack"),
+        "no wallet loaded: the grin1 Slatepack option is omitted"
+    );
     assert!(
         html.contains("http-equiv=\"refresh\""),
         "live status refresh while open"

static/goblinpay-mark.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64" role="img" aria-label="GoblinPay">
+  <rect width="64" height="64" rx="14" fill="#e9c542"/>
+  <path fill="#201d09" fill-rule="evenodd" d="M22 14H35a12 12 0 0 1 0 24H30V50H22ZM30 21H34a6 6 0 0 1 0 12H30Z"/>
+</svg>

static/goblinpay-wordmark.svg

@@ -0,0 +1,51 @@
+<?xml version="1.0" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20010904//EN"
+ "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
+<svg version="1.0" xmlns="http://www.w3.org/2000/svg"
+ width="600.000000pt" height="232.000000pt" viewBox="0 0 600.000000 232.000000"
+ preserveAspectRatio="xMidYMid meet">
+<g transform="translate(0.000000,232.000000) scale(0.050000,-0.050000)"
+fill="#ffffff" stroke="none">
+<path d="M52 4522 c-131 -444 37 -874 416 -1064 l122 -61 -95 11 c-111 13
+-226 67 -324 154 -83 72 -86 66 -28 -48 140 -278 398 -434 715 -434 197 0 331
+45 362 120 62 150 316 340 520 391 271 67 273 570 2 813 -194 175 -626 253
+-842 152 l-70 -33 91 -1 c191 -4 428 -112 506 -231 36 -53 15 -72 -26 -23 -89
+108 -361 154 -623 104 -384 -72 -552 -22 -664 197 l-30 60 -32 -107z"/>
+<path d="M4560 2533 l0 -1610 285 3 285 4 5 573 6 573 484 9 c534 10 636 29
+838 158 583 370 592 1348 15 1718 -240 155 -320 167 -1163 175 l-755 7 0
+-1610z m1450 1080 c389 -170 416 -801 42 -998 -75 -40 -118 -44 -497 -51
+l-415 -8 0 554 0 554 395 -8 c319 -7 410 -15 475 -43z"/>
+<path d="M3139 3938 c-92 -222 -202 -268 -639 -268 -462 0 -625 -70 -783 -338
+-58 -100 -60 -71 -4 66 37 92 27 95 -96 29 -298 -160 -537 -548 -537 -871 0
+-117 -1 -117 -150 -4 -124 94 -359 217 -456 240 l-55 13 43 -108 c23 -59 67
+-230 98 -381 87 -422 215 -636 412 -686 l94 -23 -4 -152 c-8 -255 71 -431 252
+-564 108 -79 133 -87 119 -36 -6 19 -16 75 -24 125 l-14 90 86 -87 c155 -155
+391 -243 648 -243 238 1 257 17 94 80 -148 58 -352 193 -453 300 l-60 63 150
+-81 c278 -149 618 -181 915 -86 79 25 130 33 138 20 43 -71 324 -122 433 -79
+31 12 26 23 -37 83 -138 133 -143 166 -41 260 116 107 160 201 145 310 -11 78
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+23 64 51 c95 74 147 190 147 330 0 142 -10 158 -45 74z m-172 -1574 c115 -128
+161 -505 71 -595 -162 -162 -289 -89 -286 164 3 327 112 544 215 431z m-1030
+-33 c101 -52 201 -243 241 -459 71 -385 -574 -317 -668 70 -55 226 234 489
+427 389z m1703 -77 c0 -181 -102 -341 -141 -222 l-24 74 -27 -63 c-47 -112
+-128 -19 -128 146 0 76 37 97 54 31 12 -47 46 -54 46 -9 0 48 62 61 92 19 26
+-35 27 -35 41 2 37 103 87 116 87 22z m-2770 -34 c16 -73 41 -77 58 -10 33
+129 140 -19 128 -177 l-6 -83 -43 66 -42 66 -13 -51 c-14 -56 -66 -69 -85 -21
+-17 45 -36 36 -61 -30 -50 -132 -103 -48 -68 108 39 175 108 243 132 132z
+m1350 -837 c0 -123 205 -183 399 -116 109 38 122 31 46 -24 -212 -151 -633
+-30 -516 148 43 65 71 62 71 -8z"/>
+<path d="M7910 3299 c-533 -109 -818 -523 -817 -1189 0 -436 84 -696 300 -929
+341 -369 1014 -413 1335 -88 l90 92 -13 -78 c-7 -42 -13 -99 -14 -127 l-1 -50
+250 -6 c138 -3 270 -1 295 6 l45 11 0 1159 0 1160 -281 0 -281 0 14 -125 14
+-125 -82 84 c-183 188 -531 271 -854 205z m590 -485 c333 -171 432 -878 177
+-1262 -222 -336 -773 -264 -938 121 -297 691 196 1430 761 1141z"/>
+<path d="M9680 3249 c0 -6 211 -496 469 -1090 l469 -1078 -84 -201 c-162 -386
+-315 -476 -665 -388 l-49 12 0 -231 c0 -269 -11 -255 217 -268 402 -22 736
+151 909 470 43 81 553 1429 994 2630 l57 155 -296 0 -295 0 -256 -730 c-141
+-402 -260 -726 -265 -722 -5 5 -146 331 -314 725 l-305 717 -293 6 c-161 3
+-293 0 -293 -7z"/>
+</g>
+</svg>

static/style.css

@@ -31,6 +31,9 @@ main {
 
 main.admin { max-width: 60rem; }
 
+.brand { display: block; }
+.brandmark { height: 30px; width: auto; display: block; margin: 0 0 1.25rem; }
+
 h1 { font-size: 1.5rem; margin: 0 0 0.5rem; }
 h2 { font-size: 1.05rem; margin: 1.75rem 0 0.5rem; color: var(--dim); text-transform: uppercase; letter-spacing: 0.04em; }
 
@@ -92,6 +95,11 @@ details.manual { margin-top: 1.5rem; border-top: 1px solid var(--line); padding-
 details.manual summary { cursor: pointer; color: var(--accent); font-weight: 600; }
 details.manual ol { color: var(--dim); font-size: 0.9rem; padding-left: 1.2rem; }
 
+/* Each first-class way to pay (Goblin/Nostr, Slatepack/grin1). */
+.pay-method { margin-top: 1.5rem; border-top: 1px solid var(--line); padding-top: 0.75rem; }
+.pay-method:first-of-type { border-top: none; padding-top: 0; }
+.pay-method ol { color: var(--dim); font-size: 0.9rem; padding-left: 1.2rem; }
+
 a { color: var(--accent); }
 
 .footer { margin-top: 2rem; color: var(--dim); font-size: 0.78rem; text-align: center; }

templates/pay.html

@@ -9,6 +9,7 @@
 </head>
 <body>
 <main class="checkout">
+  <a class="brand" href="/"><img class="brandmark" src="/static/goblinpay-wordmark.svg" alt="GoblinPay"></a>
   <h1>Pay with Goblin</h1>
   <p class="amount">{{ info.amount_display }}</p>
 
@@ -19,30 +20,37 @@
     <p class="status expired">This invoice has expired.</p>
   {% else %}
     <p class="status open">Waiting for payment&#8230;</p>
-    <div class="qr">{{ info.qr_svg|safe }}</div>
-    <p class="hint">Scan with your Goblin Wallet, or copy the address below.</p>
 
-    <label for="nprofile">Payment address (nprofile)</label>
+    {% if !info.nprofile.is_empty() %}
-    <textarea id="nprofile" class="copybox" rows="3" readonly>{{ info.nprofile }}</textarea>
+    <section class="pay-method">
+      <h2>Pay with Goblin Wallet</h2>
+      <div class="qr">{{ info.qr_svg|safe }}</div>
+      <p class="hint">Scan with your Goblin Wallet, or copy the address below.</p>
+      <label for="nprofile">Payment address (nprofile)</label>
+      <textarea id="nprofile" class="copybox" rows="3" readonly>{{ info.nprofile }}</textarea>
+    </section>
+    {% endif %}
 
-    <details class="manual">
+    {% if let Some(grin1) = info.slatepack_address %}
-      <summary>Can&#39;t scan? Pay manually with a slatepack</summary>
+    <section class="pay-method">
-      {% if wallet_available %}
+      <h2>Pay by Slatepack (grin1)</h2>
+      <p class="hint">Pay from any Grin wallet, no Nostr needed. Send <strong>{{ info.amount_display }}</strong> to the address below.</p>
+      {% if let Some(grin1_qr) = info.slatepack_qr_svg %}<div class="qr">{{ grin1_qr|safe }}</div>{% endif %}
+      <label for="grin1">Slatepack address (grin1)</label>
+      <textarea id="grin1" class="copybox" rows="3" readonly>{{ grin1 }}</textarea>
       <ol>
-        <li>In your wallet, send {{ info.amount_display }} using the manual / slatepack option.</li>
+        <li>In your Grin wallet, send {{ info.amount_display }} to this address using the Slatepack / file method, then paste the Slatepack it produces below.</li>
-        <li>Paste the generated <strong>S1</strong> slatepack below and submit.</li>
+        <li>The pasted <strong>S1</strong> Slatepack is received here and a <strong>response</strong> Slatepack is returned.</li>
-        <li>Copy the <strong>response</strong> slatepack we return, back into your wallet to finalize and post.</li>
+        <li>Paste that response back into your wallet to finalize and broadcast it, which completes the payment.</li>
       </ol>
       <form method="post" action="/pay/{{ info.token }}/slatepack">
-        <label for="s1">Your slatepack (S1)</label>
+        <label for="s1">Your Slatepack (S1)</label>
         <textarea id="s1" name="slatepack" rows="6" required
           placeholder="BEGINSLATEPACK. &#8230; ENDSLATEPACK."></textarea>
         <button type="submit">Submit slatepack</button>
       </form>
-      {% else %}
+    </section>
-      <p>Manual receive is unavailable on this instance.</p>
+    {% endif %}
-      {% endif %}
-    </details>
   {% endif %}
 
   {% if let Some(memo) = info.memo %}<p class="memo">{{ memo }}</p>{% endif %}

templates/pay_result.html

@@ -16,7 +16,7 @@
     <textarea id="s2" class="copybox" rows="8" readonly>{{ s2_armor }}</textarea>
     <ol>
       <li>Select all of the text above and copy it.</li>
-      <li>Paste it back into your wallet to finalize the transaction.</li>
+      <li>Paste it back into your wallet to finalize and broadcast the transaction; this completes the payment.</li>
       <li>Your wallet posts it to the chain; GoblinPay confirms it on receipt.</li>
     </ol>
   {% endif %}