diff --git a/bindings/rust/evmc-client/Cargo.toml b/bindings/rust/evmc-client/Cargo.toml
index 7e252a227..63e7abae3 100644
--- a/bindings/rust/evmc-client/Cargo.toml
+++ b/bindings/rust/evmc-client/Cargo.toml
@@ -15,3 +15,4 @@ edition = "2018"
 evmc-sys = { path = "../evmc-sys", version = "7.4.0" }
 evmc-vm = { path = "../evmc-vm", version = "7.4.0" }
 libloading = "0.5"
+lazy_static = "1.4.0"
diff --git a/bindings/rust/evmc-client/src/host.rs b/bindings/rust/evmc-client/src/host.rs
index 728525348..464445fca 100644
--- a/bindings/rust/evmc-client/src/host.rs
+++ b/bindings/rust/evmc-client/src/host.rs
@@ -5,9 +5,37 @@
 
 use crate::types::*;
 use evmc_sys as ffi;
+use lazy_static::lazy_static;
+use std::collections::HashMap;
 use std::mem;
+use std::sync::Mutex;
 
-pub trait HostInterface {
+#[repr(C)]
+pub(crate) struct ExtendedContext {
+    pub index: i64,
+}
+
+static mut HOST_CONTEXT_COUNTER: i64 = 0;
+
+lazy_static! {
+    static ref HOST_CONTEXT_MAP: Mutex<HashMap<i64, Box<dyn HostContext + Send + Sync>>> =
+        Mutex::new(HashMap::new());
+}
+
+pub(crate) unsafe fn add_host_context(ctx: Box<dyn HostContext + Send + Sync>) -> i64 {
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let id = HOST_CONTEXT_COUNTER;
+    HOST_CONTEXT_COUNTER += 1;
+    map.insert(id, ctx);
+    return id;
+}
+
+pub(crate) fn remove_host_context(id: i64) {
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    map.remove(&id);
+}
+
+pub trait HostContext {
     fn account_exists(&mut self, addr: &Address) -> bool;
     fn get_storage(&mut self, addr: &Address, key: &Bytes32) -> Bytes32;
     fn set_storage(&mut self, addr: &Address, key: &Bytes32, value: &Bytes32) -> StorageStatus;
@@ -38,27 +66,7 @@ pub trait HostInterface {
     ) -> (Vec<u8>, i64, Address, StatusCode);
 }
 
-struct Callback {
-    host_interface: ::std::option::Option<Box<dyn HostInterface>>,
-}
-
-static mut CALLBACK: Callback = Callback {
-    host_interface: None,
-};
-
-pub fn set_host_interface(interface: Option<Box<dyn HostInterface>>) {
-    unsafe {
-        CALLBACK.host_interface = interface;
-    }
-}
-
-pub fn get_evmc_host_context() -> ffi::evmc_host_context {
-    ffi::evmc_host_context {
-        _bindgen_opaque_blob: [0u8; 0],
-    }
-}
-
-pub fn get_evmc_host_interface() -> ffi::evmc_host_interface {
+pub(crate) fn get_evmc_host_interface() -> ffi::evmc_host_interface {
     ffi::evmc_host_interface {
         account_exists: Some(account_exists),
         get_storage: Some(get_storage),
@@ -76,197 +84,159 @@ pub fn get_evmc_host_interface() -> ffi::evmc_host_interface {
 }
 
 unsafe extern "C" fn account_exists(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
 ) -> bool {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return host_interface.account_exists(&(*address).bytes);
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return host_interface.account_exists(&(*address).bytes);
 }
 
 unsafe extern "C" fn get_storage(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
     key: *const ffi::evmc_bytes32,
 ) -> ffi::evmc_bytes32 {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return ffi::evmc_bytes32 {
-                bytes: host_interface.get_storage(&(*address).bytes, &(*key).bytes),
-            };
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return ffi::evmc_bytes32 {
+        bytes: host_interface.get_storage(&(*address).bytes, &(*key).bytes),
+    };
 }
 
 unsafe extern "C" fn set_storage(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
     key: *const ffi::evmc_bytes32,
     value: *const ffi::evmc_bytes32,
 ) -> ffi::evmc_storage_status {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return host_interface.set_storage(&(*address).bytes, &(*key).bytes, &(*value).bytes);
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return host_interface.set_storage(&(*address).bytes, &(*key).bytes, &(*value).bytes);
 }
 
 unsafe extern "C" fn get_balance(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
 ) -> ffi::evmc_uint256be {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return ffi::evmc_uint256be {
-                bytes: host_interface.get_balance(&(*address).bytes),
-            };
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return ffi::evmc_uint256be {
+        bytes: host_interface.get_balance(&(*address).bytes),
+    };
 }
 
 unsafe extern "C" fn get_code_size(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
 ) -> usize {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return host_interface.get_code_size(&(*address).bytes);
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return host_interface.get_code_size(&(*address).bytes);
 }
 
 unsafe extern "C" fn get_code_hash(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
 ) -> ffi::evmc_bytes32 {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return ffi::evmc_bytes32 {
-                bytes: host_interface.get_code_hash(&(*address).bytes),
-            };
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return ffi::evmc_bytes32 {
+        bytes: host_interface.get_code_hash(&(*address).bytes),
+    };
 }
 
 unsafe extern "C" fn copy_code(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
     code_offset: usize,
     buffer_data: *mut u8,
     buffer_size: usize,
 ) -> usize {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return host_interface.copy_code(
-                &(*address).bytes,
-                &code_offset,
-                &buffer_data,
-                &buffer_size,
-            );
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return host_interface.copy_code(&(*address).bytes, &code_offset, &buffer_data, &buffer_size);
 }
 
 unsafe extern "C" fn selfdestruct(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
     beneficiary: *const ffi::evmc_address,
 ) {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            host_interface.selfdestruct(&(*address).bytes, &(*beneficiary).bytes)
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    host_interface.selfdestruct(&(*address).bytes, &(*beneficiary).bytes)
 }
 
-unsafe extern "C" fn get_tx_context(_context: *mut ffi::evmc_host_context) -> ffi::evmc_tx_context {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            let (gas_price, origin, coinbase, number, timestamp, gas_limit, difficulty, chain_id) =
-                host_interface.get_tx_context();
-            return ffi::evmc_tx_context {
-                tx_gas_price: evmc_sys::evmc_bytes32 { bytes: gas_price },
-                tx_origin: evmc_sys::evmc_address { bytes: origin },
-                block_coinbase: evmc_sys::evmc_address { bytes: coinbase },
-                block_number: number,
-                block_timestamp: timestamp,
-                block_gas_limit: gas_limit,
-                block_difficulty: evmc_sys::evmc_bytes32 { bytes: difficulty },
-                chain_id: evmc_sys::evmc_bytes32 { bytes: chain_id },
-            };
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+unsafe extern "C" fn get_tx_context(context: *mut ffi::evmc_host_context) -> ffi::evmc_tx_context {
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    let (gas_price, origin, coinbase, number, timestamp, gas_limit, difficulty, chain_id) =
+        host_interface.get_tx_context();
+    return ffi::evmc_tx_context {
+        tx_gas_price: evmc_sys::evmc_bytes32 { bytes: gas_price },
+        tx_origin: evmc_sys::evmc_address { bytes: origin },
+        block_coinbase: evmc_sys::evmc_address { bytes: coinbase },
+        block_number: number,
+        block_timestamp: timestamp,
+        block_gas_limit: gas_limit,
+        block_difficulty: evmc_sys::evmc_bytes32 { bytes: difficulty },
+        chain_id: evmc_sys::evmc_bytes32 { bytes: chain_id },
+    };
 }
 
 unsafe extern "C" fn get_block_hash(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     number: i64,
 ) -> ffi::evmc_bytes32 {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            return ffi::evmc_bytes32 {
-                bytes: host_interface.get_block_hash(number),
-            };
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    return ffi::evmc_bytes32 {
+        bytes: host_interface.get_block_hash(number),
+    };
 }
 
 unsafe extern "C" fn emit_log(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     address: *const ffi::evmc_address,
     data: *const u8,
     data_size: usize,
     topics: *const ffi::evmc_bytes32,
     topics_count: usize,
 ) {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            let ts = &std::slice::from_raw_parts(topics, topics_count)
-                .iter()
-                .map(|topic| topic.bytes)
-                .collect::<Vec<_>>();
-            host_interface.emit_log(
-                &(*address).bytes,
-                &ts,
-                &std::slice::from_raw_parts(data, data_size),
-            );
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    let ts = &std::slice::from_raw_parts(topics, topics_count)
+        .iter()
+        .map(|topic| topic.bytes)
+        .collect::<Vec<_>>();
+    host_interface.emit_log(
+        &(*address).bytes,
+        &ts,
+        &std::slice::from_raw_parts(data, data_size),
+    );
 }
 
 unsafe extern "C" fn release(result: *const ffi::evmc_result) {
@@ -277,39 +247,36 @@ unsafe extern "C" fn release(result: *const ffi::evmc_result) {
 }
 
 pub unsafe extern "C" fn call(
-    _context: *mut ffi::evmc_host_context,
+    context: *mut ffi::evmc_host_context,
     msg: *const ffi::evmc_message,
 ) -> ffi::evmc_result {
-    match &mut CALLBACK.host_interface {
-        Some(host_interface) => {
-            let msg = *msg;
-            let (output, gas_left, create_address, status_code) = host_interface.call(
-                msg.kind,
-                &msg.destination.bytes,
-                &msg.sender.bytes,
-                &msg.value.bytes,
-                &std::slice::from_raw_parts(msg.input_data, msg.input_size),
-                msg.gas,
-                msg.depth,
-                msg.flags != 0,
-            );
-            let ptr = output.as_ptr();
-            let len = output.len();
-            mem::forget(output);
-            return ffi::evmc_result {
-                status_code: status_code,
-                gas_left: gas_left,
-                output_data: ptr,
-                output_size: len,
-                release: Some(release),
-                create_address: ffi::evmc_address {
-                    bytes: create_address,
-                },
-                padding: [0u8; 4],
-            };
-        }
-        None => {
-            panic!("Host context not implemented");
-        }
-    }
+    let mut map = HOST_CONTEXT_MAP.lock().unwrap();
+    let host_interface = map
+        .get_mut(&(*(context as *const ExtendedContext)).index)
+        .unwrap();
+    let msg = *msg;
+    let (output, gas_left, create_address, status_code) = host_interface.call(
+        msg.kind,
+        &msg.destination.bytes,
+        &msg.sender.bytes,
+        &msg.value.bytes,
+        &std::slice::from_raw_parts(msg.input_data, msg.input_size),
+        msg.gas,
+        msg.depth,
+        msg.flags != 0,
+    );
+    let ptr = output.as_ptr();
+    let len = output.len();
+    mem::forget(output);
+    return ffi::evmc_result {
+        status_code: status_code,
+        gas_left: gas_left,
+        output_data: ptr,
+        output_size: len,
+        release: Some(release),
+        create_address: ffi::evmc_address {
+            bytes: create_address,
+        },
+        padding: [0u8; 4],
+    };
 }
diff --git a/bindings/rust/evmc-client/src/lib.rs b/bindings/rust/evmc-client/src/lib.rs
index 666d2d1cd..c1f895805 100644
--- a/bindings/rust/evmc-client/src/lib.rs
+++ b/bindings/rust/evmc-client/src/lib.rs
@@ -7,7 +7,6 @@ pub mod host;
 mod loader;
 pub mod types;
 pub use self::loader::EvmcLoaderErrorCode;
-
 use crate::loader::evmc_load_and_create;
 use crate::types::*;
 use evmc_sys as ffi;
@@ -39,7 +38,6 @@ fn error(err: EvmcLoaderErrorCode) -> Result<EvmcLoaderErrorCode, &'static str>
 
 pub struct EvmcVm {
     handle: *mut ffi::evmc_vm,
-    host_context: *mut ffi::evmc_host_context,
     host_interface: *mut ffi::evmc_host_interface,
 }
 
@@ -71,7 +69,7 @@ impl EvmcVm {
 
     pub fn execute(
         &self,
-        host_interface: Box<dyn host::HostInterface>,
+        ctx: Box<dyn host::HostContext + Send + Sync>,
         rev: Revision,
         kind: MessageKind,
         is_static: bool,
@@ -84,15 +82,12 @@ impl EvmcVm {
         code: &Bytes,
         create2_salt: &Bytes32,
     ) -> (&Bytes, i64, StatusCode) {
-        host::set_host_interface(Some(host_interface));
-        let evmc_destination = ffi::evmc_address {
-            bytes: *destination,
-        };
-        let evmc_sender = ffi::evmc_address { bytes: *sender };
-        let evmc_value = ffi::evmc_uint256be { bytes: *value };
-        let evmc_create2_salt = ffi::evmc_bytes32 {
-            bytes: *create2_salt,
-        };
+        let ext_ctx: *mut host::ExtendedContext;
+        unsafe {
+            ext_ctx = Box::into_raw(Box::new(host::ExtendedContext {
+                index: host::add_host_context(ctx),
+            }));
+        }
         let mut evmc_flags: u32 = 0;
         unsafe {
             if is_static {
@@ -106,26 +101,29 @@ impl EvmcVm {
                 flags: evmc_flags,
                 depth: depth,
                 gas: gas,
-                destination: evmc_destination,
-                sender: evmc_sender,
+                destination: ffi::evmc_address {
+                    bytes: *destination,
+                },
+                sender: ffi::evmc_address { bytes: *sender },
                 input_data: input.as_ptr(),
                 input_size: input.len(),
-                value: evmc_value,
-                create2_salt: evmc_create2_salt,
+                value: ffi::evmc_uint256be { bytes: *value },
+                create2_salt: ffi::evmc_bytes32 {
+                    bytes: *create2_salt,
+                },
             }
         }));
-
         unsafe {
             let result = ((*self.handle).execute.unwrap())(
                 self.handle,
                 self.host_interface,
-                self.host_context,
+                ext_ctx as *mut ffi::evmc_host_context,
                 rev,
                 evmc_message,
                 code.as_ptr(),
                 code.len(),
             );
-            host::set_host_interface(None);
+            host::remove_host_context((*ext_ctx).index);
             return (
                 std::slice::from_raw_parts(result.output_data, result.output_size),
                 result.gas_left,
@@ -147,7 +145,6 @@ pub fn load(fname: &str) -> (EvmcVm, Result<EvmcLoaderErrorCode, &'static str>)
     (
         EvmcVm {
             handle: instance,
-            host_context: Box::into_raw(Box::new(host::get_evmc_host_context())),
             host_interface: Box::into_raw(Box::new(host::get_evmc_host_interface())),
         },
         error(ec),
@@ -158,7 +155,6 @@ pub fn create() -> EvmcVm {
     unsafe {
         EvmcVm {
             handle: evmc_create(),
-            host_context: Box::into_raw(Box::new(host::get_evmc_host_context())),
             host_interface: Box::into_raw(Box::new(host::get_evmc_host_interface())),
         }
     }