diff --git a/CHANGELOG.md b/CHANGELOG.md
index 353c6fb..bdacbf8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 All notable changes to the Sharpy smart contract are documented here.
 
 ## [Unreleased]
+- feat(contract): whitelist enforced uniformly in `pay`/`pay_with_tip`/`pool_pay` + `is_whitelisted_payer(id, payer)` view; `require!` message consistency — feat/whitelist-consistency (closes #194)
 - feat(contract): `get_tranche_remaining_bps(id)` view + cumulative-bps invariant (`released + remaining == 10000`) — feat/tranche-remaining (closes #193)
 - feat(contract): `resolve_route_chain(id, max_depth)` bounded follower + `get_route_chain_len(id)` cycle-safe depth view — feat/route-chain-depth (closes #192)
 - feat(contract): `get_stream_state(id)` + `preview_vested(id)` pure views; `withdraw_vested` repeat-withdraw idempotency fix (`total - vested`), cancel edge docs — feat/stream-vest-preview (closes #191)
diff --git a/contracts/sharpy/src/lib.rs b/contracts/sharpy/src/lib.rs
index 76cf63d..8a2b6bb 100644
--- a/contracts/sharpy/src/lib.rs
+++ b/contracts/sharpy/src/lib.rs
@@ -104,10 +104,11 @@ fn bump_counter(env: &Env) -> u64 {
 }
 
 /// Pay-guard: when a whitelist exists and is non-empty, only listed payers pass.
+/// Enforced identically in `pay`, `pay_with_tip`, and `pool_pay` (closes #194).
 fn require_whitelisted(env: &Env, invoice_id: u64, payer: &Address) {
     if let Some(state) = env.storage().persistent().get::<(Symbol,u64), WhitelistState>(&whitelist_key(invoice_id)) {
         if !state.payers.is_empty() {
-            assert!(state.payers.contains(payer), "payer not whitelisted");
+            require!(state.payers.contains(payer), "payer not whitelisted");
         }
     }
 }
@@ -402,6 +403,7 @@ impl SharpyContract {
         // Phase 1: Validate all invoices and group totals by token
         let mut token_totals: Map<Address, i128> = Map::new(&env);
         for p in payments.iter() {
+            require_whitelisted(&env, p.invoice_id, &payer);
             let inv = load_invoice(&env, p.invoice_id);
             assert!(inv.status == InvoiceStatus::Pending, "invoice is not pending");
             assert!(p.amount > 0, "payment amount must be positive");
@@ -981,6 +983,7 @@ impl SharpyContract {
     pub fn pay_with_tip(env: Env, payer: Address, invoice_id: u64, amount: i128, tip: i128) {
         require_not_paused(&env);
         payer.require_auth();
+        require_whitelisted(&env, invoice_id, &payer);
         assert!(amount > 0, "payment amount must be positive");
         assert!(tip >= 0, "tip must be non-negative");
 
@@ -1485,6 +1488,16 @@ impl SharpyContract {
         calc_protocol_fee(&env, total)
     }
 
+    /// True when `payer` may pay `invoice_id`: open when no whitelist exists
+    /// or the list is empty, else only when listed. Pure view mirroring
+    /// `require_whitelisted` enforcement across `pay`/`pay_with_tip`/`pool_pay`.
+    pub fn is_whitelisted_payer(env: Env, invoice_id: u64, payer: Address) -> bool {
+        match env.storage().persistent().get::<(Symbol,u64), WhitelistState>(&whitelist_key(invoice_id)) {
+            None => true,
+            Some(s) => s.payers.is_empty() || s.payers.contains(&payer),
+        }
+    }
+
     /// Set the payer whitelist for `invoice_id` (creator-only; empty = open).
     pub fn set_whitelist(env: Env, caller: Address, invoice_id: u64, payers: Vec<Address>) {
         caller.require_auth();
diff --git a/contracts/sharpy/src/test.rs b/contracts/sharpy/src/test.rs
index faae5c2..918ba17 100644
--- a/contracts/sharpy/src/test.rs
+++ b/contracts/sharpy/src/test.rs
@@ -5621,3 +5621,142 @@ mod test_tranche_invariant_c {
         client.release_tranche(&other, &id, &100u32);
     }
 }
+
+#[cfg(test)]
+mod test_wl_consistency_a {
+    use soroban_sdk::{testutils::Address as _, token, Address, Env, Vec};
+    use crate::SharpyContractClient;
+    fn setup() -> (Env, SharpyContractClient<'static>) {
+        let env = Env::default();
+        env.mock_all_auths();
+        let cid = env.register(crate::SharpyContract, ());
+        let c = SharpyContractClient::new(&env, &cid);
+        let a = Address::generate(&env);
+        let t = Address::generate(&env);
+        c.initialize(&a, &t);
+        (env, c)
+    }
+    fn mk(env: &Env, client: &SharpyContractClient<'_>, creator: &Address, payer: &Address, amt: i128) -> u64 {
+        let admin = Address::generate(env);
+        let tok = env.register_stellar_asset_contract(admin.clone());
+        token::StellarAssetClient::new(env, &tok).mint(payer, &(amt * 2));
+        let r = Address::generate(env);
+        let dl = env.ledger().timestamp() + 86400;
+        let opts = crate::types::InvoiceOptions { escrow_enabled: false, escrow_release_delay: None, split_rules: Vec::new(env), auto_resolve_rules: Vec::new(env), arbitrator: None };
+        client.create_invoice(creator, &Vec::from_array(env, [r]), &Vec::from_array(env, [amt]), &Vec::from_array(env, [tok]), &dl, &opts)
+    }
+    #[test]
+    fn test_view_open_when_no_list() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let payer = Address::generate(&env);
+        let id = mk(&env, &client, &creator, &payer, 1000i128);
+        assert!(client.is_whitelisted_payer(&id, &payer));
+    }
+    #[test]
+    fn test_view_empty_means_open() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let payer = Address::generate(&env);
+        let id = mk(&env, &client, &creator, &payer, 1000i128);
+        client.set_whitelist(&creator, &id, &Vec::new(&env));
+        assert!(client.is_whitelisted_payer(&id, &payer));
+    }
+}
+
+#[cfg(test)]
+mod test_wl_consistency_b {
+    use soroban_sdk::{testutils::Address as _, token, Address, Env, Vec};
+    use crate::{types::InvoicePayment, SharpyContractClient};
+    fn setup() -> (Env, SharpyContractClient<'static>) {
+        let env = Env::default();
+        env.mock_all_auths();
+        let cid = env.register(crate::SharpyContract, ());
+        let c = SharpyContractClient::new(&env, &cid);
+        let a = Address::generate(&env);
+        let t = Address::generate(&env);
+        c.initialize(&a, &t);
+        (env, c)
+    }
+    fn mk(env: &Env, client: &SharpyContractClient<'_>, creator: &Address, payer: &Address, amt: i128) -> u64 {
+        let admin = Address::generate(env);
+        let tok = env.register_stellar_asset_contract(admin.clone());
+        token::StellarAssetClient::new(env, &tok).mint(payer, &(amt * 3));
+        let r = Address::generate(env);
+        let dl = env.ledger().timestamp() + 86400;
+        let opts = crate::types::InvoiceOptions { escrow_enabled: false, escrow_release_delay: None, split_rules: Vec::new(env), auto_resolve_rules: Vec::new(env), arbitrator: None };
+        client.create_invoice(creator, &Vec::from_array(env, [r]), &Vec::from_array(env, [amt]), &Vec::from_array(env, [tok]), &dl, &opts)
+    }
+    #[test]
+    #[should_panic(expected = "payer not whitelisted")]
+    fn test_tip_path_blocked_for_stranger() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let allowed = Address::generate(&env);
+        let stranger = Address::generate(&env);
+        let id = mk(&env, &client, &creator, &stranger, 1000i128);
+        client.set_whitelist(&creator, &id, &Vec::from_array(&env, [allowed]));
+        assert!(!client.is_whitelisted_payer(&id, &stranger));
+        client.pay_with_tip(&stranger, &id, &100i128, &5i128);
+    }
+    #[test]
+    #[should_panic(expected = "payer not whitelisted")]
+    fn test_pool_path_blocked_for_stranger() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let allowed = Address::generate(&env);
+        let stranger = Address::generate(&env);
+        let id = mk(&env, &client, &creator, &stranger, 1000i128);
+        client.set_whitelist(&creator, &id, &Vec::from_array(&env, [allowed]));
+        let p = InvoicePayment { invoice_id: id, amount: 100i128 };
+        client.pool_pay(&stranger, &Vec::from_array(&env, [p]));
+    }
+}
+
+#[cfg(test)]
+mod test_wl_consistency_c {
+    use soroban_sdk::{testutils::Address as _, token, Address, Env, Vec};
+    use crate::{types::InvoicePayment, SharpyContractClient};
+    fn setup() -> (Env, SharpyContractClient<'static>) {
+        let env = Env::default();
+        env.mock_all_auths();
+        let cid = env.register(crate::SharpyContract, ());
+        let c = SharpyContractClient::new(&env, &cid);
+        let a = Address::generate(&env);
+        let t = Address::generate(&env);
+        c.initialize(&a, &t);
+        (env, c)
+    }
+    fn mk(env: &Env, client: &SharpyContractClient<'_>, creator: &Address, payer: &Address, amt: i128) -> u64 {
+        let admin = Address::generate(env);
+        let tok = env.register_stellar_asset_contract(admin.clone());
+        token::StellarAssetClient::new(env, &tok).mint(payer, &(amt * 3));
+        let r = Address::generate(env);
+        let dl = env.ledger().timestamp() + 86400;
+        let opts = crate::types::InvoiceOptions { escrow_enabled: false, escrow_release_delay: None, split_rules: Vec::new(env), auto_resolve_rules: Vec::new(env), arbitrator: None };
+        client.create_invoice(creator, &Vec::from_array(env, [r]), &Vec::from_array(env, [amt]), &Vec::from_array(env, [tok]), &dl, &opts)
+    }
+    #[test]
+    fn test_listed_payer_passes_all_paths() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let payer = Address::generate(&env);
+        let id = mk(&env, &client, &creator, &payer, 1000i128);
+        client.set_whitelist(&creator, &id, &Vec::from_array(&env, [payer.clone()]));
+        assert!(client.is_whitelisted_payer(&id, &payer));
+        client.pay_with_tip(&payer, &id, &200i128, &0i128);
+        let p = InvoicePayment { invoice_id: id, amount: 100i128 };
+        client.pool_pay(&payer, &Vec::from_array(&env, [p]));
+        assert_eq!(client.get_invoice(&id).funded, 300i128);
+    }
+    #[test]
+    fn test_view_matches_enforcement_after_remove() {
+        let (env, client) = setup();
+        let creator = Address::generate(&env);
+        let payer = Address::generate(&env);
+        let id = mk(&env, &client, &creator, &payer, 1000i128);
+        client.set_whitelist(&creator, &id, &Vec::from_array(&env, [payer.clone()]));
+        client.remove_whitelisted_payer(&creator, &id, &payer);
+        assert!(client.is_whitelisted_payer(&id, &payer));
+    }
+}