Add CashApp as a buy bitcoin provider

CLAUDE.md

@@ -138,12 +138,12 @@ See [snippets-processor/src/main.rs](docs/breez-sdk/snippets-processor/src/main.
 ## CLI Modification Policy
 
 **Do not modify language-specific CLIs** (`crates/breez-sdk/bindings/examples/cli/langs/`) unless:
-- Fixing issues caught by static analysis (clippy, linting, build errors) in those CLIs
-- Explicitly requested by the user (e.g. porting a new feature for testing)
+- Fixing failures in the **CLI matrix** or **Flutter** (which includes Flutter/Dart CLI static analysis) CI jobs. Always fix those CI failures, as this gives the Sync CLI Languages workflow (`sync-cli.yml`) better context when propagating future Rust CLI changes. Keep fixes minimal: only make changes needed to pass the build. Do not add new features, flags, or update descriptions; leave full feature propagation to the sync workflow.
+- Explicitly requested by the user (e.g. porting a new feature for testing).
 
-The **Sync CLI Languages** workflow (`sync-cli.yml`) handles propagating Rust CLI changes to all language CLIs automatically. Modifying language CLIs directly on PRs creates noise and conflicts with the sync agent.
+The **Sync CLI Languages** workflow (`sync-cli.yml`) automatically propagates Rust CLI changes to all language CLIs. Unnecessary modifications to language CLIs create PR noise.
 
-The **Rust CLI** (`crates/breez-sdk/cli/`) can be modified freely — it is the source of truth that the sync workflow reads from.
+The **Rust CLI** (`crates/breez-sdk/cli/`) can be modified freely as it is the source of truth that the sync workflow reads from.
 
 ## Workspace Configuration
 

crates/breez-sdk/bindings/examples/cli/langs/csharp/Commands.cs

@@ -932,7 +932,7 @@ private static async Task HandleBuyBitcoin(BreezSdk sdk, Func<string, string?> r
         var lockedAmountStr = GetFlag(args, "--locked-amount-sat");
         var redirectUrl = GetFlag(args, "--redirect-url");
 
-        var result = await sdk.BuyBitcoin(new BuyBitcoinRequest(
+        var result = await sdk.BuyBitcoin(new BuyBitcoinRequest.Moonpay(
             lockedAmountSat: ParseOptionalUlong(lockedAmountStr),
             redirectUrl: redirectUrl
         ));

crates/breez-sdk/bindings/examples/cli/langs/flutter/lib/commands.dart

@@ -726,7 +726,7 @@ Future<void> _handleBuyBitcoin(BreezSdk sdk, TokenIssuer tokenIssuer, List<Strin
   final redirectUrl = results.option('redirect-url');
 
   final result = await sdk.buyBitcoin(
-    request: BuyBitcoinRequest(lockedAmountSat: lockedAmount, redirectUrl: redirectUrl),
+    request: BuyBitcoinRequest_Moonpay(lockedAmountSat: lockedAmount, redirectUrl: redirectUrl),
   );
   print('Open this URL in a browser to complete the purchase:');
   print(result.url);

crates/breez-sdk/bindings/examples/cli/langs/golang/commands.go

@@ -871,7 +871,7 @@ func handleBuyBitcoin(sdk *breez_sdk_spark.BreezSdk, _ *readline.Instance, args
 		return err
 	}
 
-	req := breez_sdk_spark.BuyBitcoinRequest{}
+	req := breez_sdk_spark.BuyBitcoinRequestMoonpay{}
 	if *lockedAmount > 0 {
 		req.LockedAmountSat = lockedAmount
 	}

crates/breez-sdk/bindings/examples/cli/langs/kotlin-multiplatform/src/main/kotlin/Commands.kt

@@ -760,7 +760,7 @@ suspend fun handleBuyBitcoin(sdk: BreezSdk, reader: LineReader, args: List<Strin
     val redirectUrl = fp.getString("redirect-url")
 
     val result = sdk.buyBitcoin(
-        BuyBitcoinRequest(
+        BuyBitcoinRequest.Moonpay(
             lockedAmountSat = lockedAmount,
             redirectUrl = redirectUrl,
         )

crates/breez-sdk/bindings/examples/cli/langs/swift/Sources/BreezCLI/Commands.swift

@@ -743,7 +743,7 @@ func handleBuyBitcoin(_ sdk: BreezSdk, _ args: [String]) async throws {
     let lockedAmount = fp.get("locked-amount-sat").flatMap { UInt64($0) }
     let redirectUrl = fp.get("redirect-url")
 
-    let result = try await sdk.buyBitcoin(request: BuyBitcoinRequest(
+    let result = try await sdk.buyBitcoin(request: .moonpay(
         lockedAmountSat: lockedAmount,
         redirectUrl: redirectUrl
     ))

crates/breez-sdk/cli/src/command/mod.rs

@@ -264,13 +264,17 @@ pub enum Command {
         sat_per_vbyte: Option<u64>,
     },
     ListUnclaimedDeposits,
-    /// Buy Bitcoin using an external provider (`MoonPay`)
+    /// Buy Bitcoin using an external provider
     BuyBitcoin {
-        /// Lock the purchase to a specific amount in satoshis. When provided, the user cannot change the amount in the purchase flow.
+        /// Provider to use: "moonpay" (default) or "cashapp"
+        #[arg(long, default_value = "moonpay")]
+        provider: String,
+
+        /// Amount in satoshis (meaning depends on provider)
         #[arg(long)]
-        locked_amount_sat: Option<u64>,
+        amount_sat: Option<u64>,
 
-        /// Custom redirect URL after purchase completion
+        /// Custom redirect URL after purchase completion (`MoonPay` only)
         #[arg(long)]
         redirect_url: Option<String>,
     },
@@ -505,15 +509,20 @@ pub(crate) async fn execute_command(
             Ok(true)
         }
         Command::BuyBitcoin {
-            locked_amount_sat,
+            provider,
+            amount_sat,
             redirect_url,
         } => {
-            let value = sdk
-                .buy_bitcoin(BuyBitcoinRequest {
-                    locked_amount_sat,
+            let request = match provider.to_lowercase().as_str() {
+                "cashapp" | "cash_app" | "cash-app" => BuyBitcoinRequest::CashApp {
+                    amount_sats: amount_sat,
+                },
+                _ => BuyBitcoinRequest::Moonpay {
+                    locked_amount_sat: amount_sat,
                     redirect_url,
-                })
-                .await?;
+                },
+            };
+            let value = sdk.buy_bitcoin(request).await?;
             println!("Open this URL in a browser to complete the purchase:");
             println!("{}", value.url);
             Ok(true)

crates/breez-sdk/common/src/buy/cashapp.rs

@@ -0,0 +1,22 @@
+const CASHAPP_LIGHTNING_BASE_URL: &str = "https://cash.app/launch/lightning/";
+
+pub struct CashAppProvider;
+
+impl CashAppProvider {
+    /// Build a `CashApp` deep link URL from a bolt11 Lightning invoice.
+    pub fn build_url(invoice: &str) -> String {
+        format!("{CASHAPP_LIGHTNING_BASE_URL}{invoice}")
+    }
+}
+
+#[cfg(test)]
+pub(crate) mod tests {
+    use super::*;
+
+    #[test]
+    fn test_cashapp_url_construction() {
+        let invoice = "lnbc100n1p0abcde";
+        let url = CashAppProvider::build_url(invoice);
+        assert_eq!(url, format!("https://cash.app/launch/lightning/{invoice}"));
+    }
+}

crates/breez-sdk/common/src/buy/mod.rs

@@ -1,14 +1,2 @@
-use anyhow::Result;
-
+pub mod cashapp;
 pub mod moonpay;
-
-#[macros::async_trait]
-pub trait BuyBitcoinProviderApi: Send + Sync {
-    /// Configure buying Bitcoin and return a URL to continue
-    async fn buy_bitcoin(
-        &self,
-        address: String,
-        locked_amount_sat: Option<u64>,
-        redirect_url: Option<String>,
-    ) -> Result<String>;
-}

crates/breez-sdk/common/src/buy/moonpay.rs

@@ -1,6 +1,5 @@
 use std::sync::Arc;
 
-use super::BuyBitcoinProviderApi;
 use crate::{breez_server::BreezServer, grpc::SignUrlRequest};
 use anyhow::Result;
 use bitreq::Url;
@@ -70,11 +69,8 @@ impl MoonpayProvider {
     pub fn new(breez_server: Arc<BreezServer>) -> Self {
         Self { breez_server }
     }
-}
 
-#[macros::async_trait]
-impl BuyBitcoinProviderApi for MoonpayProvider {
-    async fn buy_bitcoin(
+    pub async fn buy_bitcoin(
         &self,
         address: String,
         locked_amount_sat: Option<u64>,

crates/breez-sdk/core/src/models/mod.rs

@@ -826,17 +826,37 @@ pub struct ListUnclaimedDepositsResponse {
     pub deposits: Vec<DepositInfo>,
 }
 
-/// Request to buy Bitcoin using an external provider (`MoonPay`)
-#[derive(Debug, Clone, Default)]
-#[cfg_attr(feature = "uniffi", derive(uniffi::Record))]
-pub struct BuyBitcoinRequest {
-    /// Optional: Lock the purchase to a specific amount in satoshis.
-    /// When provided, the user cannot change the amount in the purchase flow.
-    #[cfg_attr(feature = "uniffi", uniffi(default=None))]
-    pub locked_amount_sat: Option<u64>,
-    /// Optional: Custom redirect URL after purchase completion
-    #[cfg_attr(feature = "uniffi", uniffi(default=None))]
-    pub redirect_url: Option<String>,
+/// The available providers for buying Bitcoin
+/// Request to buy Bitcoin using an external provider.
+///
+/// Each variant carries only the parameters relevant to that provider.
+#[derive(Debug, Clone)]
+#[cfg_attr(feature = "uniffi", derive(uniffi::Enum))]
+pub enum BuyBitcoinRequest {
+    /// `MoonPay`: Fiat-to-Bitcoin via credit card, Apple Pay, etc.
+    /// Uses an on-chain deposit address.
+    Moonpay {
+        /// Lock the purchase to a specific amount in satoshis.
+        locked_amount_sat: Option<u64>,
+        /// Custom redirect URL after purchase completion.
+        redirect_url: Option<String>,
+    },
+    /// `CashApp`: Pay via the Lightning Network.
+    /// Generates a bolt11 invoice and returns a `cash.app` deep link.
+    /// Only available on mainnet.
+    CashApp {
+        /// Amount in satoshis for the Lightning invoice.
+        amount_sats: Option<u64>,
+    },
+}
+
+impl Default for BuyBitcoinRequest {
+    fn default() -> Self {
+        Self::Moonpay {
+            locked_amount_sat: None,
+            redirect_url: None,
+        }
+    }
 }
 
 /// Response containing a URL to complete the Bitcoin purchase

crates/breez-sdk/core/src/sdk/api.rs

@@ -2,12 +2,14 @@ use bitcoin::secp256k1::{PublicKey, ecdsa::Signature};
 use std::str::FromStr;
 use tracing::info;
 
+use breez_sdk_common::buy::cashapp::CashAppProvider;
+
 use crate::{
     BuyBitcoinRequest, BuyBitcoinResponse, CheckMessageRequest, CheckMessageResponse,
     GetTokensMetadataRequest, GetTokensMetadataResponse, InputType, ListFiatCurrenciesResponse,
-    ListFiatRatesResponse, OptimizationProgress, RegisterWebhookRequest, RegisterWebhookResponse,
-    SignMessageRequest, SignMessageResponse, UnregisterWebhookRequest, UpdateUserSettingsRequest,
-    UserSettings, Webhook,
+    ListFiatRatesResponse, Network, OptimizationProgress, RegisterWebhookRequest,
+    RegisterWebhookResponse, SignMessageRequest, SignMessageResponse, UnregisterWebhookRequest,
+    UpdateUserSettingsRequest, UserSettings, Webhook,
     chain::RecommendedFees,
     error::SdkError,
     events::EventListener,
@@ -320,30 +322,47 @@ impl BreezSdk {
         Ok(webhooks.into_iter().map(Into::into).collect())
     }
 
-    /// Initiates a Bitcoin purchase flow via an external provider (`MoonPay`).
-    ///
-    /// This method generates a URL that the user can open in a browser to complete
-    /// the Bitcoin purchase. The purchased Bitcoin will be sent to an automatically
-    /// generated deposit address.
+    /// Initiates a Bitcoin purchase flow via an external provider.
     ///
-    /// # Arguments
+    /// Returns a URL the user should open to complete the purchase.
+    /// The request variant determines the provider and its parameters:
     ///
-    /// * `request` - The purchase request containing optional amount and redirect URL
-    ///
-    /// # Returns
-    ///
-    /// A response containing the URL to open in a browser to complete the purchase
+    /// - [`BuyBitcoinRequest::Moonpay`]: Fiat-to-Bitcoin via on-chain deposit.
+    /// - [`BuyBitcoinRequest::CashApp`]: Lightning invoice + `cash.app` deep link (mainnet only).
     pub async fn buy_bitcoin(
         &self,
         request: BuyBitcoinRequest,
     ) -> Result<BuyBitcoinResponse, SdkError> {
-        let address = get_deposit_address(&self.spark_wallet, true).await?;
-
-        let url = self
-            .buy_bitcoin_provider
-            .buy_bitcoin(address, request.locked_amount_sat, request.redirect_url)
-            .await
-            .map_err(|e| SdkError::Generic(format!("Failed to create buy bitcoin URL: {e}")))?;
+        let url = match request {
+            BuyBitcoinRequest::Moonpay {
+                locked_amount_sat,
+                redirect_url,
+            } => {
+                let address = get_deposit_address(&self.spark_wallet, true).await?;
+                self.buy_bitcoin_provider
+                    .buy_bitcoin(address, locked_amount_sat, redirect_url)
+                    .await
+                    .map_err(|e| {
+                        SdkError::Generic(format!("Failed to create buy bitcoin URL: {e}"))
+                    })?
+            }
+            BuyBitcoinRequest::CashApp { amount_sats } => {
+                if !matches!(self.config.network, Network::Mainnet) {
+                    return Err(SdkError::Generic(
+                        "CashApp is only available on mainnet".to_string(),
+                    ));
+                }
+                let receive_response = self
+                    .receive_bolt11_invoice(
+                        "Buy Bitcoin via CashApp".to_string(),
+                        amount_sats,
+                        None,
+                        None,
+                    )
+                    .await?;
+                CashAppProvider::build_url(&receive_response.payment_request)
+            }
+        };
 
         Ok(BuyBitcoinResponse { url })
     }

crates/breez-sdk/core/src/sdk/mod.rs

@@ -12,7 +12,7 @@ mod sync_coordinator;
 pub(crate) use sync_coordinator::SyncCoordinator;
 
 use bitflags::bitflags;
-use breez_sdk_common::{buy::BuyBitcoinProviderApi, fiat::FiatService, sync::SigningClient};
+use breez_sdk_common::{buy::moonpay::MoonpayProvider, fiat::FiatService, sync::SigningClient};
 use platform_utils::HttpClient;
 use platform_utils::tokio;
 use spark_wallet::SparkWallet;
@@ -92,7 +92,7 @@ pub struct BreezSdk {
     pub(crate) spark_private_mode_initialized: Arc<OnceCell<()>>,
     pub(crate) token_converter: Arc<dyn TokenConverter>,
     pub(crate) stable_balance: Option<Arc<StableBalance>>,
-    pub(crate) buy_bitcoin_provider: Arc<dyn BuyBitcoinProviderApi>,
+    pub(crate) buy_bitcoin_provider: Arc<MoonpayProvider>,
 }
 
 pub(crate) struct BreezSdkParams {
@@ -107,7 +107,7 @@ pub(crate) struct BreezSdkParams {
     pub spark_wallet: Arc<SparkWallet>,
     pub event_emitter: Arc<EventEmitter>,
     pub sync_signing_client: Option<SigningClient>,
-    pub buy_bitcoin_provider: Arc<dyn BuyBitcoinProviderApi>,
+    pub buy_bitcoin_provider: Arc<MoonpayProvider>,
 }
 
 pub async fn parse_input(

crates/breez-sdk/core/src/sdk/payments.rs

@@ -459,7 +459,7 @@ impl BreezSdk {
 
 // Private payment methods
 impl BreezSdk {
-    async fn receive_bolt11_invoice(
+    pub(crate) async fn receive_bolt11_invoice(
         &self,
         description: String,
         amount_sats: Option<u64>,

crates/breez-sdk/core/src/sdk_builder.rs

@@ -6,7 +6,7 @@ use std::sync::Arc;
 
 use breez_sdk_common::{
     breez_server::{BreezServer, PRODUCTION_BREEZSERVER_URL},
-    buy::{BuyBitcoinProviderApi, moonpay::MoonpayProvider},
+    buy::moonpay::MoonpayProvider,
 };
 use platform_utils::DefaultHttpClient;
 
@@ -590,8 +590,7 @@ impl SdkBuilder {
             };
 
         // Create the MoonPay provider for buying Bitcoin
-        let buy_bitcoin_provider: Arc<dyn BuyBitcoinProviderApi> =
-            Arc::new(MoonpayProvider::new(breez_server.clone()));
+        let buy_bitcoin_provider = Arc::new(MoonpayProvider::new(breez_server.clone()));
 
         // Create the SDK instance
         let sdk = BreezSdk::init_and_start(BreezSdkParams {

crates/breez-sdk/wasm/src/models/mod.rs

@@ -1332,9 +1332,14 @@ pub struct SparkStatus {
 }
 
 #[macros::extern_wasm_bindgen(breez_sdk_spark::BuyBitcoinRequest)]
-pub struct BuyBitcoinRequest {
-    pub locked_amount_sat: Option<u64>,
-    pub redirect_url: Option<String>,
+pub enum BuyBitcoinRequest {
+    Moonpay {
+        locked_amount_sat: Option<u64>,
+        redirect_url: Option<String>,
+    },
+    CashApp {
+        amount_sats: Option<u64>,
+    },
 }
 
 #[macros::extern_wasm_bindgen(breez_sdk_spark::BuyBitcoinResponse)]