diff --git a/Cargo.lock b/Cargo.lock
index 41e96f8db..e05fe290c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1827,6 +1827,19 @@ dependencies = [
  "fvm_shared 4.0.0",
 ]
 
+[[package]]
+name = "fil_custom_syscall_actor"
+version = "0.1.0"
+dependencies = [
+ "cid 0.10.1",
+ "fvm_ipld_encoding 0.4.0",
+ "fvm_sdk 4.0.0",
+ "fvm_shared 4.0.0",
+ "num-traits",
+ "serde",
+ "serde_tuple",
+]
+
 [[package]]
 name = "fil_events_actor"
 version = "0.1.0"
@@ -2445,6 +2458,7 @@ dependencies = [
 name = "fvm_integration_tests"
 version = "4.0.0"
 dependencies = [
+ "ambassador",
  "anyhow",
  "blake2b_simd",
  "bls-signatures",
@@ -2456,6 +2470,7 @@ dependencies = [
  "fvm_ipld_blockstore 0.2.0",
  "fvm_ipld_car 0.7.1",
  "fvm_ipld_encoding 0.4.0",
+ "fvm_sdk 4.0.0",
  "fvm_shared 4.0.0",
  "fvm_test_actors",
  "hex",
diff --git a/Cargo.toml b/Cargo.toml
index b18dfa44b..3ade4472f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -65,6 +65,7 @@ ahash = "0.8.3"
 itertools = "0.11.0"
 once_cell = "1.18.0"
 unsigned-varint = "0.7.2"
+ambassador = "0.3.5"
 
 # dev/tools/tests
 criterion = "0.5.1"
diff --git a/fvm/Cargo.toml b/fvm/Cargo.toml
index 55b247af2..2faa140f1 100644
--- a/fvm/Cargo.toml
+++ b/fvm/Cargo.toml
@@ -36,6 +36,7 @@ once_cell = { workspace = true }
 minstant = { workspace = true }
 blake2b_simd = { workspace = true }
 byteorder = { workspace = true }
+ambassador = { workspace = true }
 derive_more = "0.99.17"
 replace_with = "0.1.7"
 filecoin-proofs-api = { version = "16", default-features = false }
@@ -44,7 +45,6 @@ num_cpus = "1.15.0"
 fvm-wasm-instrument = "0.4.0"
 yastl = "0.1.2"
 static_assertions = "1.1.0"
-ambassador = "0.3.5"
 
 [dev-dependencies]
 pretty_assertions = "1.3.0"
diff --git a/testing/integration/Cargo.toml b/testing/integration/Cargo.toml
index 37c80364c..e54b968e7 100644
--- a/testing/integration/Cargo.toml
+++ b/testing/integration/Cargo.toml
@@ -13,6 +13,7 @@ fvm_shared = { workspace = true, features = ["testing"] }
 fvm_ipld_car = { workspace = true }
 fvm_ipld_blockstore = { workspace = true }
 fvm_ipld_encoding = { workspace = true }
+fvm_sdk = { workspace = true }
 
 anyhow = { workspace = true }
 cid = { workspace = true }
@@ -26,6 +27,7 @@ rand_chacha = { workspace = true }
 serde = { workspace = true }
 serde_tuple = { workspace = true }
 thiserror = { workspace = true }
+ambassador = { workspace = true }
 wasmtime = { workspace = true, default-features = false, features = ["cranelift", "parallel-compilation"] }
 
 [dev-dependencies]
diff --git a/testing/integration/src/custom_kernel/mod.rs b/testing/integration/src/custom_kernel/mod.rs
new file mode 100644
index 000000000..d84f1ce23
--- /dev/null
+++ b/testing/integration/src/custom_kernel/mod.rs
@@ -0,0 +1,201 @@
+// Copyright 2021-2023 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+use fvm::call_manager::CallManager;
+use fvm::gas::Gas;
+use fvm::kernel::filecoin::{DefaultFilecoinKernel, FilecoinKernel};
+use fvm::kernel::prelude::*;
+use fvm::kernel::Result;
+use fvm::kernel::{
+    ActorOps, CryptoOps, DebugOps, EventOps, IpldBlockOps, MessageOps, NetworkOps, RandomnessOps,
+    SelfOps, SendOps, SyscallHandler, UpgradeOps,
+};
+use fvm::syscalls::Linker;
+use fvm_shared::clock::ChainEpoch;
+use fvm_shared::consensus::ConsensusFault;
+use fvm_shared::piece::PieceInfo;
+use fvm_shared::randomness::RANDOMNESS_LENGTH;
+use fvm_shared::sector::{
+    AggregateSealVerifyProofAndInfos, RegisteredSealProof, ReplicaUpdateInfo, SealVerifyInfo,
+};
+use fvm_shared::sys::out::network::NetworkContext;
+use fvm_shared::sys::out::vm::MessageContext;
+use fvm_shared::{address::Address, econ::TokenAmount, ActorID, MethodNum};
+
+use ambassador::Delegate;
+use cid::Cid;
+
+// we define a single custom syscall which simply doubles the input
+pub trait CustomKernel: Kernel {
+    fn my_custom_syscall(&self, doubleme: i32) -> Result<i32>;
+}
+
+// our custom kernel extends the filecoin kernel
+#[derive(Delegate)]
+#[delegate(IpldBlockOps, where = "C: CallManager")]
+#[delegate(ActorOps, where = "C: CallManager")]
+#[delegate(CryptoOps, where = "C: CallManager")]
+#[delegate(DebugOps, where = "C: CallManager")]
+#[delegate(EventOps, where = "C: CallManager")]
+#[delegate(MessageOps, where = "C: CallManager")]
+#[delegate(NetworkOps, where = "C: CallManager")]
+#[delegate(RandomnessOps, where = "C: CallManager")]
+#[delegate(SelfOps, where = "C: CallManager")]
+#[delegate(SendOps<K>, generics = "K", where = "K: CustomKernel")]
+#[delegate(UpgradeOps<K>, generics = "K", where = "K: CustomKernel")]
+pub struct DefaultCustomKernel<C>(pub DefaultFilecoinKernel<C>);
+
+impl<C> CustomKernel for DefaultCustomKernel<C>
+where
+    C: CallManager,
+    DefaultCustomKernel<C>: Kernel,
+{
+    fn my_custom_syscall(&self, doubleme: i32) -> Result<i32> {
+        Ok(doubleme * 2)
+    }
+}
+
+impl<C> DefaultCustomKernel<C>
+where
+    C: CallManager,
+{
+    fn price_list(&self) -> &PriceList {
+        (self.0).0.call_manager.price_list()
+    }
+}
+
+impl<C> Kernel for DefaultCustomKernel<C>
+where
+    C: CallManager,
+{
+    type CallManager = C;
+    type Limiter = <DefaultFilecoinKernel<C> as Kernel>::Limiter;
+
+    fn into_inner(self) -> (Self::CallManager, BlockRegistry)
+    where
+        Self: Sized,
+    {
+        self.0.into_inner()
+    }
+
+    fn new(
+        mgr: C,
+        blocks: BlockRegistry,
+        caller: ActorID,
+        actor_id: ActorID,
+        method: MethodNum,
+        value_received: TokenAmount,
+        read_only: bool,
+    ) -> Self {
+        DefaultCustomKernel(DefaultFilecoinKernel::new(
+            mgr,
+            blocks,
+            caller,
+            actor_id,
+            method,
+            value_received,
+            read_only,
+        ))
+    }
+
+    fn machine(&self) -> &<Self::CallManager as CallManager>::Machine {
+        self.0.machine()
+    }
+
+    fn limiter_mut(&mut self) -> &mut Self::Limiter {
+        self.0.limiter_mut()
+    }
+
+    fn gas_available(&self) -> Gas {
+        self.0.gas_available()
+    }
+
+    fn charge_gas(&self, name: &str, compute: Gas) -> Result<GasTimer> {
+        self.0.charge_gas(name, compute)
+    }
+}
+
+impl<C> FilecoinKernel for DefaultCustomKernel<C>
+where
+    C: CallManager,
+{
+    fn compute_unsealed_sector_cid(
+        &self,
+        proof_type: RegisteredSealProof,
+        pieces: &[PieceInfo],
+    ) -> Result<Cid> {
+        self.0.compute_unsealed_sector_cid(proof_type, pieces)
+    }
+
+    fn verify_post(&self, verify_info: &fvm_shared::sector::WindowPoStVerifyInfo) -> Result<bool> {
+        self.0.verify_post(verify_info)
+    }
+
+    // NOT forwarded
+    fn batch_verify_seals(&self, vis: &[SealVerifyInfo]) -> Result<Vec<bool>> {
+        Ok(vec![true; vis.len()])
+    }
+
+    // NOT forwarded
+    fn verify_consensus_fault(
+        &self,
+        h1: &[u8],
+        h2: &[u8],
+        extra: &[u8],
+    ) -> Result<Option<ConsensusFault>> {
+        let charge = self
+            .price_list()
+            .on_verify_consensus_fault(h1.len(), h2.len(), extra.len());
+        let _ = self.charge_gas(&charge.name, charge.total())?;
+        Ok(None)
+    }
+
+    // NOT forwarded
+    fn verify_aggregate_seals(&self, agg: &AggregateSealVerifyProofAndInfos) -> Result<bool> {
+        let charge = self.price_list().on_verify_aggregate_seals(agg);
+        let _ = self.charge_gas(&charge.name, charge.total())?;
+        Ok(true)
+    }
+
+    // NOT forwarded
+    fn verify_replica_update(&self, rep: &ReplicaUpdateInfo) -> Result<bool> {
+        let charge = self.price_list().on_verify_replica_update(rep);
+        let _ = self.charge_gas(&charge.name, charge.total())?;
+        Ok(true)
+    }
+
+    fn total_fil_circ_supply(&self) -> Result<TokenAmount> {
+        self.0.total_fil_circ_supply()
+    }
+}
+
+impl<K> SyscallHandler<K> for DefaultCustomKernel<K::CallManager>
+where
+    K: CustomKernel
+        + FilecoinKernel
+        + ActorOps
+        + SendOps
+        + UpgradeOps
+        + IpldBlockOps
+        + CryptoOps
+        + DebugOps
+        + EventOps
+        + MessageOps
+        + NetworkOps
+        + RandomnessOps
+        + SelfOps,
+{
+    fn link_syscalls(linker: &mut Linker<K>) -> anyhow::Result<()> {
+        DefaultFilecoinKernel::<K::CallManager>::link_syscalls(linker)?;
+
+        linker.link_syscall("my_custom_kernel", "my_custom_syscall", my_custom_syscall)?;
+
+        Ok(())
+    }
+}
+
+pub fn my_custom_syscall(
+    context: fvm::syscalls::Context<'_, impl CustomKernel>,
+    doubleme: i32,
+) -> Result<i32> {
+    context.kernel.my_custom_syscall(doubleme)
+}
diff --git a/testing/integration/src/lib.rs b/testing/integration/src/lib.rs
index 706162647..835a5e32e 100644
--- a/testing/integration/src/lib.rs
+++ b/testing/integration/src/lib.rs
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0, MIT
 mod builtin;
 pub mod bundle;
+pub mod custom_kernel;
 pub mod dummy;
 pub mod error;
 pub mod tester;
diff --git a/testing/integration/src/tester.rs b/testing/integration/src/tester.rs
index af5b229ab..bb4f28f56 100644
--- a/testing/integration/src/tester.rs
+++ b/testing/integration/src/tester.rs
@@ -6,7 +6,6 @@ use fvm::call_manager::DefaultCallManager;
 use fvm::engine::EnginePool;
 use fvm::executor::DefaultExecutor;
 use fvm::externs::Externs;
-use fvm::kernel::filecoin::DefaultFilecoinKernel;
 use fvm::machine::{DefaultMachine, Machine, MachineContext, NetworkConfig};
 use fvm::state_tree::{ActorState, StateTree};
 use fvm::{init_actor, system_actor};
@@ -24,6 +23,7 @@ use multihash::Code;
 use crate::builtin::{
     fetch_builtin_code_cid, set_burnt_funds_account, set_eam_actor, set_init_actor, set_sys_actor,
 };
+use crate::custom_kernel::DefaultCustomKernel;
 use crate::dummy::DummyExterns;
 use crate::error::Error::{FailedToFlushTree, NoManifestInformation};
 
@@ -36,7 +36,7 @@ lazy_static! {
 pub trait Store: Blockstore + Sized + 'static {}
 
 pub type IntegrationExecutor<B, E> =
-    DefaultExecutor<DefaultFilecoinKernel<DefaultCallManager<DefaultMachine<B, E>>>>;
+    DefaultExecutor<DefaultCustomKernel<DefaultCallManager<DefaultMachine<B, E>>>>;
 
 pub type Account = (ActorID, Address);
 
@@ -298,7 +298,7 @@ where
         let machine = DefaultMachine::new(&mc, blockstore, externs)?;
 
         let executor = DefaultExecutor::<
-            DefaultFilecoinKernel<DefaultCallManager<DefaultMachine<B, E>>>,
+            DefaultCustomKernel<DefaultCallManager<DefaultMachine<B, E>>>,
         >::new(engine, machine)?;
 
         self.executor = Some(executor);
diff --git a/testing/integration/tests/main.rs b/testing/integration/tests/main.rs
index d2345f5ec..0b83f0a5d 100644
--- a/testing/integration/tests/main.rs
+++ b/testing/integration/tests/main.rs
@@ -20,9 +20,9 @@ use fvm_shared::message::Message;
 use fvm_shared::state::StateTreeVersion;
 use fvm_shared::version::NetworkVersion;
 use fvm_test_actors::wasm_bin::{
-    ADDRESS_ACTOR_BINARY, CREATE_ACTOR_BINARY, EXIT_DATA_ACTOR_BINARY, HELLO_WORLD_ACTOR_BINARY,
-    IPLD_ACTOR_BINARY, OOM_ACTOR_BINARY, READONLY_ACTOR_BINARY, SSELF_ACTOR_BINARY,
-    STACK_OVERFLOW_ACTOR_BINARY, SYSCALL_ACTOR_BINARY, UPGRADE_ACTOR_BINARY,
+    ADDRESS_ACTOR_BINARY, CREATE_ACTOR_BINARY, CUSTOM_SYSCALL_ACTOR_BINARY, EXIT_DATA_ACTOR_BINARY,
+    HELLO_WORLD_ACTOR_BINARY, IPLD_ACTOR_BINARY, OOM_ACTOR_BINARY, READONLY_ACTOR_BINARY,
+    SSELF_ACTOR_BINARY, STACK_OVERFLOW_ACTOR_BINARY, SYSCALL_ACTOR_BINARY, UPGRADE_ACTOR_BINARY,
     UPGRADE_RECEIVE_ACTOR_BINARY,
 };
 use num_traits::Zero;
@@ -1108,6 +1108,57 @@ fn readonly_actor_tests() {
     assert!(res.msg_receipt.events_root.is_none());
 }
 
+#[test]
+fn custom_syscall() {
+    // Instantiate tester
+    let mut tester = new_tester(
+        NetworkVersion::V21,
+        StateTreeVersion::V5,
+        MemoryBlockstore::default(),
+    )
+    .unwrap();
+
+    let [(_sender_id, sender_address)] = tester.create_accounts().unwrap();
+
+    let wasm_bin = CUSTOM_SYSCALL_ACTOR_BINARY;
+
+    // Set actor state
+    let actor_state = [(); 0];
+    let state_cid = tester.set_state(&actor_state).unwrap();
+
+    // Set actor
+    let actor_address = Address::new_id(10000);
+
+    tester
+        .set_actor_from_bin(wasm_bin, state_cid, actor_address, TokenAmount::zero())
+        .unwrap();
+
+    // Instantiate machine
+    tester.instantiate_machine(DummyExterns).unwrap();
+
+    let executor = tester.executor.as_mut().unwrap();
+
+    let message = Message {
+        from: sender_address,
+        to: actor_address,
+        gas_limit: 1000000000,
+        method_num: 1,
+        sequence: 0,
+        value: TokenAmount::from_atto(100),
+        ..Message::default()
+    };
+
+    let res = executor
+        .execute_message(message, ApplyKind::Explicit, 100)
+        .unwrap();
+
+    assert!(
+        res.msg_receipt.exit_code.is_success(),
+        "{:?}",
+        res.failure_info
+    );
+}
+
 #[test]
 fn upgrade_actor_test() {
     // inline function to calculate cid from address
diff --git a/testing/test_actors/actors/fil-custom-syscall/Cargo.toml b/testing/test_actors/actors/fil-custom-syscall/Cargo.toml
new file mode 100644
index 000000000..ffd683dfd
--- /dev/null
+++ b/testing/test_actors/actors/fil-custom-syscall/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+name = "fil_custom_syscall_actor"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+fvm_sdk = { workspace = true }
+fvm_shared = { workspace = true }
+fvm_ipld_encoding = { workspace = true }
+cid = { workspace = true }
+serde = { workspace = true }
+serde_tuple = { workspace = true }
+num-traits = { workspace = true }
+
+[lib]
+crate-type = ["cdylib"] ## cdylib is necessary for Wasm build
diff --git a/testing/test_actors/actors/fil-custom-syscall/src/actor.rs b/testing/test_actors/actors/fil-custom-syscall/src/actor.rs
new file mode 100644
index 000000000..be08a02b1
--- /dev/null
+++ b/testing/test_actors/actors/fil-custom-syscall/src/actor.rs
@@ -0,0 +1,18 @@
+// Copyright 2021-2023 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+fvm_sdk::sys::fvm_syscalls! {
+    module = "my_custom_kernel";
+    pub fn my_custom_syscall(doubleme: i32) -> Result<i32>;
+}
+
+#[no_mangle]
+pub fn invoke(_: u32) -> u32 {
+    fvm_sdk::initialize();
+
+    unsafe {
+        let value = my_custom_syscall(11).unwrap();
+        assert_eq!(value, 22, "expected 22, got {}", value);
+    }
+
+    0
+}
diff --git a/testing/test_actors/actors/fil-custom-syscall/src/lib.rs b/testing/test_actors/actors/fil-custom-syscall/src/lib.rs
new file mode 100644
index 000000000..1d4daedef
--- /dev/null
+++ b/testing/test_actors/actors/fil-custom-syscall/src/lib.rs
@@ -0,0 +1,4 @@
+// Copyright 2021-2023 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+#[cfg(target_arch = "wasm32")]
+mod actor;
diff --git a/testing/test_actors/build.rs b/testing/test_actors/build.rs
index a3f118cb7..d5fdfa71f 100644
--- a/testing/test_actors/build.rs
+++ b/testing/test_actors/build.rs
@@ -33,6 +33,7 @@ const ACTORS: &[(&str, &str)] = &[
     ("SSELF_ACTOR_BINARY", "fil_sself_actor"),
     ("UPGRADE_ACTOR_BINARY", "fil_upgrade_actor"),
     ("UPGRADE_RECEIVE_ACTOR_BINARY", "fil_upgrade_receive_actor"),
+    ("CUSTOM_SYSCALL_ACTOR_BINARY", "fil_custom_syscall_actor"),
 ];
 
 const WASM_TARGET: &str = "wasm32-unknown-unknown";