diff --git a/src/ripple/app/hook/HookAPI.h b/src/ripple/app/hook/HookAPI.h
index 04c534dd6..d9b8e19d2 100644
--- a/src/ripple/app/hook/HookAPI.h
+++ b/src/ripple/app/hook/HookAPI.h
@@ -1,9 +1,4 @@
-// A decoupled Hook host API helper for programmatic use and testing.
-// Provides selected Hook APIs (emit-related and dependencies) without any
-// dependency on WASM memory. It operates directly on ripple types.
-
-#pragma once
-
+#include <ripple/app/hook/Enum.h>
 #include <ripple/app/tx/impl/ApplyContext.h>
 #include <ripple/basics/Blob.h>
 #include <ripple/basics/Expected.h>
@@ -14,6 +9,8 @@
 #include <cstdint>
 
 namespace hook {
+using namespace ripple;
+using HookReturnCode = hook_api::hook_return_code;
 
 struct HookContext;  // defined in applyHook.h
 
@@ -26,21 +23,21 @@ public:
 
     // Emit a transaction from the running hook. On success, returns 32-byte
     // transaction ID bytes (same content written by the wasm host function).
-    ripple::Expected<std::shared_ptr<ripple::Transaction>, std::int64_t>
-    emit(ripple::Slice txBlob);
+    Expected<std::shared_ptr<Transaction>, HookReturnCode>
+    emit(Slice txBlob);
 
     // Dependencies (public so callers can compose):
     // etxn_generation == otxn_generation() + 1
-    std::int64_t
+    uint32_t
     etxn_generation() const;
-    std::int64_t
+    Expected<uint64_t, HookReturnCode>
     etxn_burden() const;
-    std::int64_t
-    etxn_fee_base(ripple::Slice txBlob) const;
+    Expected<uint64_t, HookReturnCode>
+    etxn_fee_base(Slice txBlob) const;
 
-    std::int64_t
+    uint32_t
     otxn_generation() const;
-    std::int64_t
+    uint64_t
     otxn_burden() const;
 
 private:
diff --git a/src/ripple/app/hook/impl/HookAPI.cpp b/src/ripple/app/hook/impl/HookAPI.cpp
index d0a80352c..739a3ed2a 100644
--- a/src/ripple/app/hook/impl/HookAPI.cpp
+++ b/src/ripple/app/hook/impl/HookAPI.cpp
@@ -16,7 +16,7 @@ namespace hook {
 
 using namespace ripple;
 
-std::int64_t
+uint64_t
 HookAPI::otxn_burden() const
 {
     auto& applyCtx = hookCtx.applyCtx;
@@ -41,13 +41,13 @@ HookAPI::otxn_burden() const
         return 1;
     }
 
-    std::uint64_t burden = pd.getFieldU64(sfEmitBurden);
+    uint64_t burden = pd.getFieldU64(sfEmitBurden);
     burden &= ((1ULL << 63) - 1);
     hookCtx.burden = burden;
-    return static_cast<std::int64_t>(burden);
+    return static_cast<int64_t>(burden);
 }
 
-std::int64_t
+uint32_t
 HookAPI::otxn_generation() const
 {
     auto& applyCtx = hookCtx.applyCtx;
@@ -76,34 +76,34 @@ HookAPI::otxn_generation() const
     return hookCtx.generation;
 }
 
-std::int64_t
+uint32_t
 HookAPI::etxn_generation() const
 {
     return otxn_generation() + 1;
 }
 
-std::int64_t
+Expected<uint64_t, HookReturnCode>
 HookAPI::etxn_burden() const
 {
     if (hookCtx.expected_etxn_count <= -1)
-        return hook_api::PREREQUISITE_NOT_MET;
+        return Unexpected(hook_api::PREREQUISITE_NOT_MET);
 
-    std::uint64_t last_burden = static_cast<std::uint64_t>(otxn_burden());
-    std::uint64_t burden =
-        last_burden * static_cast<std::uint64_t>(hookCtx.expected_etxn_count);
+    uint64_t last_burden = static_cast<uint64_t>(otxn_burden());
+    uint64_t burden =
+        last_burden * static_cast<uint64_t>(hookCtx.expected_etxn_count);
     if (burden < last_burden)
-        return hook_api::FEE_TOO_LARGE;
-    return static_cast<std::int64_t>(burden);
+        return Unexpected(hook_api::FEE_TOO_LARGE);
+    return burden;
 }
 
-std::int64_t
+Expected<uint64_t, HookReturnCode>
 HookAPI::etxn_fee_base(ripple::Slice txBlob) const
 {
     auto& applyCtx = hookCtx.applyCtx;
     auto j = applyCtx.app.journal("View");
 
     if (hookCtx.expected_etxn_count <= -1)
-        return hook_api::PREREQUISITE_NOT_MET;
+        return Unexpected(hook_api::PREREQUISITE_NOT_MET);
 
     try
     {
@@ -118,11 +118,11 @@ HookAPI::etxn_fee_base(ripple::Slice txBlob) const
     {
         JLOG(j.trace()) << "HookInfo[" << HC_ACC()
                         << "]: etxn_fee_base exception: " << e.what();
-        return hook_api::INVALID_TXN;
+        return Unexpected(hook_api::INVALID_TXN);
     }
 }
 
-ripple::Expected<std::shared_ptr<Transaction>, std::int64_t>
+Expected<std::shared_ptr<Transaction>, HookReturnCode>
 HookAPI::emit(ripple::Slice txBlob)
 {
     auto& applyCtx = hookCtx.applyCtx;
@@ -130,10 +130,10 @@ HookAPI::emit(ripple::Slice txBlob)
     auto& view = applyCtx.view();
 
     if (hookCtx.expected_etxn_count < 0)
-        return ripple::Unexpected<std::int64_t>(hook_api::PREREQUISITE_NOT_MET);
+        return Unexpected(hook_api::PREREQUISITE_NOT_MET);
 
     if (hookCtx.result.emittedTxn.size() >= hookCtx.expected_etxn_count)
-        return ripple::Unexpected<std::int64_t>(hook_api::TOO_MANY_EMITTED_TXN);
+        return Unexpected(hook_api::TOO_MANY_EMITTED_TXN);
 
     std::shared_ptr<STTx const> stpTrans;
     try
@@ -144,14 +144,14 @@ HookAPI::emit(ripple::Slice txBlob)
     catch (std::exception const& e)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC() << "]: Failed " << e.what();
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (isPseudoTx(*stpTrans))
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: Attempted to emit pseudo txn.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     ripple::TxType txType = stpTrans->getTxnType();
@@ -161,7 +161,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: Hook cannot emit this txn.";
-        return ripple::Unexpected<std::uint64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // check the emitted txn is valid
@@ -184,7 +184,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfAccount does not match hook account";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 1: sfSequence must be present and 0
@@ -193,7 +193,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfSequence missing or non-zero";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 2: sfSigningPubKey must be present and 00...00
@@ -201,7 +201,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfSigningPubKey missing";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     auto const pk = stpTrans->getSigningPubKey();
@@ -209,7 +209,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfSigningPubKey present but wrong size";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     for (int i = 0; i < pk.size(); ++i)
@@ -217,7 +217,7 @@ HookAPI::emit(ripple::Slice txBlob)
         {
             JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                             << "]: sfSigningPubKey present but non-zero.";
-            return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+            return Unexpected(hook_api::EMISSION_FAILURE);
         }
 
     // rule 2.a: no signers
@@ -225,7 +225,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfSigners not allowed in emitted txns.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 2.b: ticketseq cannot be used
@@ -233,7 +233,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfTicketSequence not allowed in emitted txns.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 2.c sfAccountTxnID not allowed
@@ -241,7 +241,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfAccountTxnID not allowed in emitted txns.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 3: sfEmitDetails must be present and valid
@@ -249,7 +249,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitDetails missing.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     auto const& emitDetails = const_cast<ripple::STTx&>(*stpTrans)
@@ -264,7 +264,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitDetails malformed.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 8: emit generation cannot exceed 10
@@ -272,7 +272,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitGeneration was 10 or more.";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     auto const gen = emitDetails.getFieldU32(sfEmitGeneration);
@@ -286,7 +286,7 @@ HookAPI::emit(ripple::Slice txBlob)
 
     auto const& hash = emitDetails.getFieldH256(sfEmitHookHash);
 
-    std::uint32_t gen_proper = static_cast<std::uint32_t>(etxn_generation());
+    uint32_t gen_proper = static_cast<uint32_t>(etxn_generation());
 
     if (gen != gen_proper)
     {
@@ -294,17 +294,17 @@ HookAPI::emit(ripple::Slice txBlob)
                         << "]: sfEmitGeneration provided in EmitDetails "
                         << "not correct (" << gen << ") "
                         << "should be " << gen_proper;
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
-    std::uint64_t bur_proper = static_cast<std::uint64_t>(etxn_burden());
+    uint64_t bur_proper = static_cast<uint64_t>(etxn_burden().value());
     if (bur != bur_proper)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitBurden provided in EmitDetails "
                         << "was not correct (" << bur << ") "
                         << "should be " << bur_proper;
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (pTxnID != applyCtx.tx.getTransactionID())
@@ -312,7 +312,7 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitParentTxnID provided in EmitDetails"
                         << "was not correct";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (hookCtx.nonce_used.find(nonce) == hookCtx.nonce_used.end())
@@ -320,7 +320,7 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitNonce provided in EmitDetails was not "
                            "generated by nonce api";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (callback && *callback != hookCtx.result.account)
@@ -328,7 +328,7 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfEmitCallback account must be the account of "
                            "the emitting hook";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (hash != hookCtx.result.hookHash)
@@ -336,7 +336,7 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace())
             << "HookEmit[" << HC_ACC()
             << "]: sfEmitHookHash must be the hash of the emitting hook";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 4: sfTxnSignature must be absent
@@ -344,7 +344,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfTxnSignature is present but should not be";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 5: LastLedgerSeq must be present and after current ledger
@@ -352,17 +352,17 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfLastLedgerSequence missing";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
-    std::uint32_t tx_lls = stpTrans->getFieldU32(sfLastLedgerSequence);
-    std::uint32_t ledgerSeq = view.info().seq;
+    uint32_t tx_lls = stpTrans->getFieldU32(sfLastLedgerSequence);
+    uint32_t ledgerSeq = view.info().seq;
     if (tx_lls < ledgerSeq + 1)
     {
         JLOG(j.trace())
             << "HookEmit[" << HC_ACC()
             << "]: sfLastLedgerSequence invalid (less than next ledger)";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (tx_lls > ledgerSeq + 5)
@@ -370,7 +370,7 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace())
             << "HookEmit[" << HC_ACC()
             << "]: sfLastLedgerSequence cannot be greater than current seq + 5";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 6
@@ -380,32 +380,32 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: sfFirstLedgerSequence must be present and <= "
                            "LastLedgerSequence";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // rule 7 check the emitted txn pays the appropriate fee
-    std::int64_t minfee = etxn_fee_base(txBlob);
+    int64_t minfee = etxn_fee_base(txBlob).value();
 
     if (minfee < 0)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: Fee could not be calculated";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     if (!stpTrans->isFieldPresent(sfFee))
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: Fee missing from emitted tx";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
-    std::int64_t fee = stpTrans->getFieldAmount(sfFee).xrp().drops();
+    int64_t fee = stpTrans->getFieldAmount(sfFee).xrp().drops();
     if (fee < minfee)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: Fee less than minimum required";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     std::string reason;
@@ -415,7 +415,7 @@ HookAPI::emit(ripple::Slice txBlob)
     {
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: tpTrans->getStatus() != NEW";
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     // preflight the transaction
@@ -431,7 +431,7 @@ HookAPI::emit(ripple::Slice txBlob)
         JLOG(j.trace()) << "HookEmit[" << HC_ACC()
                         << "]: Transaction preflight failure: "
                         << preflightResult.ter;
-        return ripple::Unexpected<std::int64_t>(hook_api::EMISSION_FAILURE);
+        return Unexpected(hook_api::EMISSION_FAILURE);
     }
 
     return tpTrans;
diff --git a/src/ripple/app/hook/impl/applyHook.cpp b/src/ripple/app/hook/impl/applyHook.cpp
index e619b0a69..7790744fe 100644
--- a/src/ripple/app/hook/impl/applyHook.cpp
+++ b/src/ripple/app/hook/impl/applyHook.cpp
@@ -3490,7 +3490,10 @@ DEFINE_HOOK_FUNCNARG(int64_t, etxn_burden)
 {
     HOOK_SETUP();
     hook::HookAPI api(hookCtx);
-    return api.etxn_burden();
+    auto const burden = api.etxn_burden();
+    if (!burden)
+        return burden.error();
+    return burden.value();
     HOOK_TEARDOWN();
 }
 
@@ -4280,7 +4283,10 @@ DEFINE_HOOK_FUNCTION(
     hook::HookAPI api(hookCtx);
     ripple::Slice tx{
         reinterpret_cast<const void*>(read_ptr + memory), read_len};
-    return api.etxn_fee_base(tx);
+    auto const fee_base = api.etxn_fee_base(tx);
+    if (!fee_base)
+        return fee_base.error();
+    return fee_base.value();
     HOOK_TEARDOWN();
 }
 
diff --git a/src/ripple/basics/Expected.h b/src/ripple/basics/Expected.h
index bb699579b..b919e9fd6 100644
--- a/src/ripple/basics/Expected.h
+++ b/src/ripple/basics/Expected.h
@@ -137,14 +137,14 @@ class [[nodiscard]] Expected
 public:
     template <typename U>
     requires std::convertible_to<U, T> constexpr Expected(U && r)
-        : Base(T(std::forward<U>(r)))
+        : Base(boost::outcome_v2::success(T(std::forward<U>(r))))
     {
     }
 
     template <typename U>
         requires std::convertible_to<U, E> &&
         (!std::is_reference_v<U>)constexpr Expected(Unexpected<U> e)
-        : Base(E(std::move(e.value())))
+        : Base(boost::outcome_v2::failure(E(std::move(e.value()))))
     {
     }
 
@@ -220,7 +220,7 @@ public:
     template <typename U>
         requires std::convertible_to<U, E> &&
         (!std::is_reference_v<U>)constexpr Expected(Unexpected<U> e)
-        : Base(E(std::move(e.value())))
+        : Base(boost::outcome_v2::failure(E(std::move(e.value()))))
     {
     }