feat(pumpfun): runtime V2 flag, buyback fee pool fix, legacy ix encoding

- Replace compile-time `pumpfun-v2` feature flag with runtime
  `TradeConfig::use_pumpfun_v2(bool)` for flexible V1/V2 switching
- Fix BUYBACK_FEE_RECIPIENTS pool: replace wrong addresses (was reusing
  standard pool + FEE_CONFIG) with official buyback pool from
  FEE_RECIPIENTS.md
- Fix legacy buy/buy_exact_sol_in ix data encoding: use 2-byte
  Option<bool> (option tag + value) matching official Pump SDK, 26 bytes
  total instead of broken 25
- Add `SwapParams.use_pumpfun_v2` field and wire through TradingClient
  buy/sell paths
- V2 instructions read `quote_mint` from `PumpFunParams` (not
  BondingCurveAccount which lacks the field)
- Fix `fetch_bonding_curve_account` to use BorshDeserialize instead of
  non-existent `decode_from_chain_account_data`
- Update all examples with `use_pumpfun_v2: false` field
- Update README with unified V1/V2 section showing both enabling methods

README.md

@@ -53,6 +53,7 @@
   - [🔍 Address Lookup Tables](#-address-lookup-tables)
   - [🔍 Nonce Cache](#-nonce-cache)
 - [💰 Cashback Support (PumpFun / PumpSwap)](#-cashback-support-pumpfun--pumpswap)
+- [🔄 PumpFun V1 vs V2 Instructions](#-pumpfun-v1-vs-v2-instructions)
 - [🛡️ MEV Protection Services](#️-mev-protection-services)
 - [📁 Project Structure](#-project-structure)
 - [📄 License](#-license)
@@ -145,6 +146,7 @@ let trade_config = TradeConfig::builder(rpc_url, swqos_configs, commitment)
     // .check_min_tip(false)               // default: false - filter SWQOS below min tip
     // .swqos_cores_from_end(false)        // default: false - bind SWQOS to last N CPU cores
     // .mev_protection(false)              // default: false - MEV (Astralane QUIC :9000 or HTTP mev-protect / BlockRazor)
+    // .use_pumpfun_v2(false)             // default: false - V1 (18 accounts); set true for V2 (27 accounts, quote_mint) when PumpFun deploys V2
     .build();
 
 // Create TradingClient
@@ -347,49 +349,58 @@ Some PumpFun coins use **Creator Rewards Sharing**, so the on-chain `creator_vau
 
 The SDK does not fetch creator_vault from RPC on every sell (to avoid latency); pass the up-to-date vault from gRPC/events when available.
 
-#### PumpSwap: coin_creator_vault from events (no RPC)
+#### PumpFun V1 vs V2 Instructions
 
-For **PumpSwap** (Pump AMM), `coin_creator_vault_ata` and `coin_creator_vault_authority` are required in buy/sell instructions. Both are available from parsed events without RPC:
+PumpFun has two instruction sets for bonding-curve trading:
 
-- **sol-parser-sdk**: Instruction parser sets them from accounts 17 and 18; the account filler also fills them when the event comes from logs. Use `PumpSwapParams::from_trade(..., e.coin_creator_vault_ata, e.coin_creator_vault_authority, ...)` with the buy/sell event `e`.
-- **solana-streamer**: Instruction parser sets them from `accounts.get(17)` and `accounts.get(18)`. Use the same `from_trade` with the event’s `coin_creator_vault_ata` and `coin_creator_vault_authority`.
+| | V1 (default) | V2 (opt-in) |
+|---|---|---|
+| Instructions | `buy` / `buy_exact_sol_in` / `sell` | `buy_v2` / `buy_exact_quote_in_v2` / `sell_v2` |
+| Account metas | 18 | 27 |
+| Quote mint | SOL only (legacy) | SOL or USDC (via `quote_mint` field) |
+| Transaction size | Smaller (fits `PACKET_DATA_SIZE` without LUT) | Larger (requires LUT for most transactions) |
 
-### Pump.fun Bonding Curve v2 (buy_v2 / sell_v2 / buy_exact_quote_in_v2)
-
-Pump.fun has upgraded the Bonding Curve contract with **unified v2 instructions** that support both SOL-paired and USDC-paired coins through a single fixed account layout. The legacy `buy`/`sell`/`buy_exact_sol_in` instructions continue to work for SOL-paired coins and remain the default.
+**Default: V1** (`use_pumpfun_v2 = false`). The SDK uses V1 instructions which produce smaller transactions that fit within the 1232-byte `PACKET_DATA_SIZE` limit without requiring an Address Lookup Table.
 
 **Key changes in v2 instructions:**
-- `quote_mint` parameter — pass wrapped SOL (`So11111111111111111111111111111111111111112`) for SOL-paired, or USDC mint for USDC-paired
+- `quote_mint` parameter — pass wrapped SOL for SOL-paired, or USDC mint for USDC-paired
 - 27 fixed accounts (buy) / 26 fixed accounts (sell) — **no optional accounts**
 - `buyback_fee_recipient`, `sharing_config`, and 6 `associated_quote_*` ATAs are now mandatory
 - Same pricing and cost as legacy instructions for SOL-paired coins
 
-**Using v2 instructions:**
+**How to enable V2:**
 
-Set `quote_mint` on your `PumpFunParams`. The SDK automatically switches to `buy_v2`/`sell_v2`/`buy_exact_quote_in_v2` discriminators with the 27/26-account layout:
+**Method 1 — Global runtime flag** (recommended when PumpFun officially deploys V2 on mainnet):
+
+```rust
+let trade_config = TradeConfig::builder(rpc_url, swqos_configs, commitment)
+    .use_pumpfun_v2(true)  // Switch all PumpFun trades to V2 instructions (27 accounts)
+    .build();
+```
+
+**Method 2 — Per-trade via `quote_mint`** (for USDC-paired coins or mixed V1/V2 scenarios):
 
 ```rust
 use sol_trade_sdk::constants::WSOL_TOKEN_ACCOUNT;
 use sol_trade_sdk::constants::USDC_TOKEN_ACCOUNT;
 
-// SOL-paired coin — use wrapped SOL mint
+// SOL-paired coin with v2 layout
 let params = PumpFunParams::from_trade(/* ... */)
     .with_quote_mint(WSOL_TOKEN_ACCOUNT);
 
-// USDC-paired coin (coming soon — requires v2)
+// USDC-paired coin (requires v2)
 let params = PumpFunParams::from_trade(/* ... */)
     .with_quote_mint(USDC_TOKEN_ACCOUNT);
-
-// Then trade as usual
-client.buy(buy_params).await?;
-client.sell(sell_params).await?;
 ```
 
-| Quote Mint | `use_v2_ix` | Instruction Used | Notes |
-|-----------|-------------|-----------------|-------|
-| Not set (default) | `false` | Legacy `buy`/`sell`/`buy_exact_sol_in` | Backward compatible, SOL-only |
-| `WSOL_TOKEN_ACCOUNT` | `true` | `buy_v2`/`sell_v2`/`buy_exact_quote_in_v2` | SOL-paired, unified layout |
-| `USDC_TOKEN_ACCOUNT` | `true` | `buy_v2`/`sell_v2`/`buy_exact_quote_in_v2` | USDC-paired (requires v2) |
+> **Note**: V2 transactions with ATA creation + durable nonce may exceed `PACKET_DATA_SIZE`. Enable an Address Lookup Table (`address_lookup_table_account`) when using V2.
+
+#### PumpSwap: coin_creator_vault from events (no RPC)
+
+For **PumpSwap** (Pump AMM), `coin_creator_vault_ata` and `coin_creator_vault_authority` are required in buy/sell instructions. Both are available from parsed events without RPC:
+
+- **sol-parser-sdk**: Instruction parser sets them from accounts 17 and 18; the account filler also fills them when the event comes from logs. Use `PumpSwapParams::from_trade(..., e.coin_creator_vault_ata, e.coin_creator_vault_authority, ...)` with the buy/sell event `e`.
+- **solana-streamer**: Instruction parser sets them from `accounts.get(17)` and `accounts.get(18)`. Use the same `from_trade` with the event's `coin_creator_vault_ata` and `coin_creator_vault_authority`.
 
 ## 🛡️ MEV Protection Services
 

examples/address_lookup/src/main.rs

@@ -176,6 +176,7 @@ async fn pumpfun_copy_trade_with_grpc(
         gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/bonk_copy_trading/src/main.rs

@@ -179,6 +179,7 @@ async fn bonk_copy_trade_with_grpc(trade_info: BonkTradeEvent) -> AnyResult<()>
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/bonk_sniper_trading/src/main.rs

@@ -147,6 +147,7 @@ async fn bonk_sniper_trade_with_shreds(trade_info: BonkTradeEvent) -> AnyResult<
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/cli_trading/src/main.rs

@@ -636,6 +636,7 @@ async fn handle_buy_pumpfun(
         gas_fee_strategy: gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     match client.buy(buy_params).await {
@@ -692,6 +693,7 @@ async fn handle_buy_pumpswap(
         gas_fee_strategy: gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     match client.buy(buy_params).await {
@@ -748,6 +750,7 @@ async fn handle_buy_bonk(
         gas_fee_strategy: gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     match client.buy(buy_params).await {
@@ -808,6 +811,7 @@ async fn handle_buy_raydium_v4(
         gas_fee_strategy: gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     match client.buy(buy_params).await {
@@ -869,6 +873,7 @@ async fn handle_buy_raydium_cpmm(
         gas_fee_strategy: gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     match client.buy(buy_params).await {

examples/meteora_damm_v2_direct_trading/src/main.rs

@@ -51,6 +51,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/middleware_system/src/main.rs

@@ -112,6 +112,7 @@ async fn test_middleware() -> AnyResult<()> {
         gas_fee_strategy: gas_fee_strategy,
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/nonce_cache/src/main.rs

@@ -172,6 +172,7 @@ async fn pumpfun_copy_trade_with_grpc(
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/pumpfun_copy_trading/src/main.rs

@@ -169,6 +169,7 @@ async fn pumpfun_copy_trade(e: sol_parser_sdk::core::events::PumpFunTradeEvent)
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/pumpfun_sniper_trading/src/main.rs

@@ -159,6 +159,7 @@ async fn pumpfun_sniper_trade(e: sol_parser_sdk::core::events::PumpFunTradeEvent
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/pumpswap_direct_trading/src/main.rs

@@ -50,6 +50,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/pumpswap_trading/src/main.rs

@@ -244,6 +244,7 @@ async fn pumpswap_trade_with_grpc(
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/raydium_amm_v4_trading/src/main.rs

@@ -181,6 +181,7 @@ async fn raydium_amm_v4_copy_trade_with_grpc(trade_info: RaydiumAmmV4SwapEvent)
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/raydium_cpmm_trading/src/main.rs

@@ -169,6 +169,7 @@ async fn raydium_cpmm_copy_trade_with_grpc(trade_info: RaydiumCpmmSwapEvent) ->
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

examples/seed_trading/src/main.rs

@@ -50,6 +50,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         gas_fee_strategy: gas_fee_strategy.clone(),
         simulate: false,
         use_exact_sol_amount: None,
+            use_pumpfun_v2: false,
         grpc_recv_us: None,
     };
     client.buy(buy_params).await?;

src/client/mod.rs

@@ -303,6 +303,8 @@ pub struct TradingClient {
     pub log_enabled: bool,
     /// Whether to check minimum tip per SWQOS (from TradeConfig.check_min_tip). Default false for lower latency.
     pub check_min_tip: bool,
+    /// Use PumpFun V2 instructions (buy_v2 / sell_v2, 27-account metas). Default false.
+    pub use_pumpfun_v2: bool,
 }
 
 static INSTANCE: Mutex<Option<Arc<TradingClient>>> = Mutex::new(None);
@@ -323,6 +325,7 @@ impl Clone for TradingClient {
             effective_core_ids: self.effective_core_ids.clone(),
             log_enabled: self.log_enabled,
             check_min_tip: self.check_min_tip,
+            use_pumpfun_v2: self.use_pumpfun_v2,
         }
     }
 }
@@ -457,6 +460,7 @@ impl TradingClient {
             effective_core_ids,
             log_enabled: true,
             check_min_tip: false,
+            use_pumpfun_v2: false,
         }
     }
 
@@ -503,6 +507,7 @@ impl TradingClient {
             effective_core_ids,
             log_enabled: true,
             check_min_tip: false,
+            use_pumpfun_v2: false,
         }
     }
 
@@ -682,6 +687,7 @@ impl TradingClient {
             effective_core_ids: infrastructure.effective_core_ids.clone(),
             log_enabled: trade_config.log_enabled,
             check_min_tip: trade_config.check_min_tip,
+            use_pumpfun_v2: trade_config.use_pumpfun_v2,
         };
 
         let mut current = INSTANCE.lock();
@@ -860,6 +866,7 @@ impl TradingClient {
             check_min_tip: self.check_min_tip,
             grpc_recv_us: params.grpc_recv_us,
             use_exact_sol_amount: params.use_exact_sol_amount,
+            use_pumpfun_v2: self.use_pumpfun_v2,
         };
 
         let swap_result = executor.swap(buy_params).await;
@@ -967,6 +974,7 @@ impl TradingClient {
             check_min_tip: self.check_min_tip,
             grpc_recv_us: params.grpc_recv_us,
             use_exact_sol_amount: None,
+            use_pumpfun_v2: self.use_pumpfun_v2,
         };
 
         let swap_result = executor.swap(sell_params).await;

src/common/types.rs

@@ -95,6 +95,10 @@ pub struct TradeConfig {
     /// (Astralane QUIC `:9000` or Plain/Binary HTTP `mev-protect=true`, BlockRazor sandwichMitigation)
     /// use their MEV-protected endpoints/modes. Default false (no MEV protection, lower latency).
     pub mev_protection: bool,
+    /// Use PumpFun V2 instructions (buy_v2 / sell_v2, 27-account metas, quote_mint support).
+    /// Default: `false` — uses V1 instructions (18-account metas, legacy SOL-paired, smaller transaction).
+    /// Set to `true` when PumpFun officially deploys V2 on mainnet.
+    pub use_pumpfun_v2: bool,
 }
 
 impl TradeConfig {
@@ -149,6 +153,7 @@ pub struct TradeConfigBuilder {
     check_min_tip: bool,
     swqos_cores_from_end: bool,
     mev_protection: bool,
+    use_pumpfun_v2: bool,
 }
 
 impl TradeConfigBuilder {
@@ -163,6 +168,7 @@ impl TradeConfigBuilder {
             check_min_tip: false,
             swqos_cores_from_end: false,
             mev_protection: false,
+            use_pumpfun_v2: false,
         }
     }
 
@@ -208,6 +214,14 @@ impl TradeConfigBuilder {
         self
     }
 
+    /// Use PumpFun V2 instructions (`buy_v2` / `sell_v2`, 27-account metas, `quote_mint` support).
+    /// Default: `false` (V1 — 18-account metas, legacy SOL-paired, smaller transaction).
+    /// Set to `true` when PumpFun officially deploys V2 on mainnet.
+    pub fn use_pumpfun_v2(mut self, v: bool) -> Self {
+        self.use_pumpfun_v2 = v;
+        self
+    }
+
     /// Consume the builder and produce a [`TradeConfig`].
     pub fn build(self) -> TradeConfig {
         TradeConfig {
@@ -220,6 +234,7 @@ impl TradeConfigBuilder {
             check_min_tip: self.check_min_tip,
             swqos_cores_from_end: self.swqos_cores_from_end,
             mev_protection: self.mev_protection,
+            use_pumpfun_v2: self.use_pumpfun_v2,
         }
     }
 }

src/instruction/pumpfun_ix_data.rs

@@ -1,6 +1,9 @@
-//! Pump.fun 曲线 `buy` / `buy_exact_sol_in` / `sell` 的 **instruction data** 栈上编码（热路径零堆分配）。
+//! Pump.fun 曲线 **legacy** `buy` / `buy_exact_sol_in` / `sell` 与 **`buy_v2` / `sell_v2` / `buy_exact_quote_in_v2`**
+//! 的 instruction data 栈上编码（热路径零堆分配）。
 //!
-//! 与 `@pump-fun/pump-sdk` Anchor `coder.instruction.encode` 对齐：`OptionBool` 在 ix 参数中为 **1 字节**。
+//! Legacy `buy` / `buy_exact_sol_in` 与 `@pump-fun/pump-sdk` 对齐：`OptionBool` 在 ix 参数中为
+//! **1 字节 option tag + 1 字节值**（Anchor `Option<bool>` = 2 字节），共 26 字节 ix data。
+//! `*_v2` 指令无 `track_volume` 字节（见 [pump-public-docs](https://github.com/pump-fun/pump-public-docs)）。
 
 use crate::instruction::utils::pumpfun::{
     BUY_DISCRIMINATOR, BUY_EXACT_QUOTE_IN_V2_DISCRIMINATOR, BUY_EXACT_SOL_IN_DISCRIMINATOR,
@@ -74,10 +77,10 @@ pub fn encode_pumpfun_buy_exact_quote_in_v2_ix_data(
 }
 
 #[inline(always)]
-pub fn encode_pumpfun_sell_v2_ix_data(amount: u64, min_sol_output: u64) -> [u8; 24] {
+pub fn encode_pumpfun_sell_v2_ix_data(token_amount: u64, min_sol_output: u64) -> [u8; 24] {
     let mut d = [0u8; 24];
     d[..8].copy_from_slice(&SELL_V2_DISCRIMINATOR);
-    d[8..16].copy_from_slice(&amount.to_le_bytes());
+    d[8..16].copy_from_slice(&token_amount.to_le_bytes());
     d[16..24].copy_from_slice(&min_sol_output.to_le_bytes());
     d
 }

src/instruction/utils/pumpfun.rs

@@ -4,6 +4,7 @@
 
 use crate::common::{bonding_curve::BondingCurveAccount, SolanaRpcClient};
 use anyhow::anyhow;
+use borsh::BorshDeserialize;
 use rand::seq::IndexedRandom;
 use solana_sdk::{
     instruction::{AccountMeta, Instruction},
@@ -108,16 +109,16 @@ pub const PROTOCOL_EXTRA_FEE_RECIPIENTS: [Pubkey; 8] = [
 ];
 
 /// Buyback fee recipients (v2 account #9 in buy_v2/sell_v2).
-/// Selected randomly — distinct from main fee recipients.
+/// 对应官方 FEE_RECIPIENTS.md "Buyback (Applies to All)" 池，与主 fee_recipient 池互斥。
 pub const BUYBACK_FEE_RECIPIENTS: [Pubkey; 8] = [
-    pubkey!("CebN5WGQ4jvEPvsVU4EoHEpgzq1VV7AbicfhtW4xC9iM"),
-    pubkey!("FWsW1xNtWscwNmKv6wVsU1iTzRN6wmmk3MjxRP5tT7hz"),
-    pubkey!("G5UZAVbAf46s7cKWoyKu8kYTip9DGTpbLZ2qa9Aq69dP"),
-    pubkey!("AVmoTthdrX6tKt4nDjco2D775W2YK3sDhxPcMmzUAmTY"),
-    pubkey!("9rPYyANsfQZw3DnDmKE3YCQF5E8oD89UXoHn9JFEhJUz"),
-    pubkey!("7hTckgnGnLQR6sdH7YkqFTAA7VwTfYFaZ6EhEsU3saCX"),
-    pubkey!("7VtfL8fvgNfhz17qKRMjzQEXgbdpnHHHQRh54R9jP2RJ"),
-    pubkey!("8Wf5TiAheLUqBrKXeYg2JtAFFMWtKdG2BSFgqUcPVwTt"),
+    pubkey!("5YxQFdt3Tr9zJLvkFccqXVUwhdTWJQc1fFg2YPbxvxeD"),
+    pubkey!("9M4giFFMxmFGXtc3feFzRai56WbBqehoSeRE5GK7gf7"),
+    pubkey!("GXPFM2caqTtQYC2cJ5yJRi9VDkpsYZXzYdwYpGnLmtDL"),
+    pubkey!("3BpXnfJaUTiwXnJNe7Ej1rcbzqTTQUvLShZaWazebsVR"),
+    pubkey!("5cjcW9wExnJJiqgLjq7DEG75Pm6JBgE1hNv4B2vHXUW6"),
+    pubkey!("EHAAiTxcdDwQ3U4bU6YcMsQGaekdzLS3B5SmYo46kJtL"),
+    pubkey!("5eHhjP8JaYkz83CWwvGU2uMUXefd3AazWGx4gpcuEEYD"),
+    pubkey!("A7hAgCzFw14fejgCp387JUJRMNyz4j89JKnhtKU8piqW"),
 ];
 }
 
@@ -184,11 +185,12 @@ pub const PUMP_BONDING_CURVE_MIN_DATA_LEN: usize = 151;
 pub const BUY_DISCRIMINATOR: [u8; 8] = [102, 6, 61, 18, 1, 218, 235, 234];
 pub const BUY_EXACT_SOL_IN_DISCRIMINATOR: [u8; 8] = [56, 252, 116, 8, 158, 223, 205, 95];
 pub const SELL_DISCRIMINATOR: [u8; 8] = [51, 230, 133, 164, 1, 127, 131, 173];
-/// buy_v2: unified buy with quote_mint support (SOL + USDC), 27 fixed accounts, 2 args (no track_volume)
+
+/// `buy_v2` — unified SOL/USDC quote interface ([pump-public-docs](https://github.com/pump-fun/pump-public-docs)).
 pub const BUY_V2_DISCRIMINATOR: [u8; 8] = [184, 23, 238, 97, 103, 197, 211, 61];
-/// sell_v2: unified sell with quote_mint support (SOL + USDC), 26 fixed accounts, 2 args
+/// `sell_v2`
 pub const SELL_V2_DISCRIMINATOR: [u8; 8] = [93, 246, 130, 60, 231, 233, 64, 178];
-/// buy_exact_quote_in_v2: spend exact quote amount for min tokens out (SOL + USDC), 27 fixed accounts, 2 args
+/// `buy_exact_quote_in_v2` (native SOL spend for SOL-paired coins when `quote_mint` is WSOL)
 pub const BUY_EXACT_QUOTE_IN_V2_DISCRIMINATOR: [u8; 8] = [194, 171, 28, 70, 104, 77, 91, 47];
 
 pub const EXTEND_ACCOUNT_DISCRIMINATOR: [u8; 8] = [234, 102, 194, 203, 150, 72, 62, 229];
@@ -297,7 +299,7 @@ pub fn get_protocol_extra_fee_recipient_random() -> Pubkey {
         .unwrap_or(&global_constants::PROTOCOL_EXTRA_FEE_RECIPIENTS[0])
 }
 
-/// Random buyback fee recipient from static pool (v2 account #9 in buy_v2/sell_v2).
+/// Buyback fee recipient (#9 in buy_v2/sell_v2) — dedicated pool, distinct from protocol extra fee recipients.
 #[inline]
 pub fn get_buyback_fee_recipient_random() -> Pubkey {
     *global_constants::BUYBACK_FEE_RECIPIENTS
@@ -305,12 +307,6 @@ pub fn get_buyback_fee_recipient_random() -> Pubkey {
         .unwrap_or(&global_constants::BUYBACK_FEE_RECIPIENTS[0])
 }
 
-/// Quote token program id for a given quote_mint (both WSOL and USDC use the legacy Token Program).
-#[inline]
-pub fn get_quote_token_program(_quote_mint: &Pubkey) -> Pubkey {
-    crate::constants::TOKEN_PROGRAM
-}
-
 #[inline]
 pub fn pump_fun_fee_recipient_meta(observed_fee_recipient: Pubkey, is_mayhem_mode: bool) -> AccountMeta {
     let trust_observation = observed_fee_recipient != Pubkey::default()
@@ -549,9 +545,9 @@ pub async fn fetch_bonding_curve_account(
         return Err(anyhow!("Bonding curve not found"));
     }
 
-    let bonding_curve =
-        solana_sdk::borsh1::try_from_slice_unchecked::<BondingCurveAccount>(&account.data[8..])
-            .map_err(|e| anyhow::anyhow!("Failed to deserialize bonding curve account: {}", e))?;
+    let mut bonding_curve = BondingCurveAccount::try_from_slice(&account.data[8..])
+        .map_err(|e| anyhow::anyhow!("Failed to decode bonding curve account: {}", e))?;
+    bonding_curve.account = bonding_curve_pda;
 
     Ok((Arc::new(bonding_curve), bonding_curve_pda))
 }
@@ -573,6 +569,9 @@ mod tests {
         assert_eq!(BUY_DISCRIMINATOR.len(), 8);
         assert_eq!(BUY_EXACT_SOL_IN_DISCRIMINATOR.len(), 8);
         assert_eq!(SELL_DISCRIMINATOR.len(), 8);
+        assert_eq!(BUY_V2_DISCRIMINATOR.len(), 8);
+        assert_eq!(SELL_V2_DISCRIMINATOR.len(), 8);
+        assert_eq!(BUY_EXACT_QUOTE_IN_V2_DISCRIMINATOR.len(), 8);
     }
 
     #[test]

src/trading/core/params/dex_swap.rs

@@ -97,6 +97,10 @@ pub struct SwapParams {
     /// When Some(false), uses regular buy instruction where slippage is applied to SOL/quote input.
     /// This option only applies to PumpFun and PumpSwap DEXes; it is ignored for other DEXes.
     pub use_exact_sol_amount: Option<bool>,
+    /// Use PumpFun V2 instructions (buy_v2 / sell_v2 / buy_exact_quote_in_v2, 27-account metas, quote_mint support).
+    /// Default: `false` — uses V1 instructions (18-account metas, legacy SOL-paired).
+    /// Set to `true` when PumpFun officially deploys V2 on mainnet. Until then, keep `false` for smaller transaction size.
+    pub use_pumpfun_v2: bool,
 }
 
 impl SwapParams {