diff --git a/services/backup/blob_client/src/lib.rs b/services/backup/blob_client/src/lib.rs
--- a/services/backup/blob_client/src/lib.rs
+++ b/services/backup/blob_client/src/lib.rs
@@ -15,13 +15,20 @@
 #[cxx::bridge]
 mod ffi {
   extern "Rust" {
-    fn put_client_initialize_cxx() -> Result<()>;
+    unsafe fn put_client_initialize_cxx(
+      holder_char: *const c_char,
+    ) -> Result<()>;
     unsafe fn put_client_write_cxx(
+      holder_char: *const c_char,
       field_index: usize,
       data: *const c_char,
     ) -> Result<()>;
-    fn put_client_blocking_read_cxx() -> Result<String>;
-    fn put_client_terminate_cxx() -> Result<()>;
+    unsafe fn put_client_blocking_read_cxx(
+      holder_char: *const c_char,
+    ) -> Result<String>;
+    unsafe fn put_client_terminate_cxx(
+      holder_char: *const c_char,
+    ) -> Result<()>;
     unsafe fn get_client_initialize_cxx(
       holder_char: *const c_char,
     ) -> Result<()>;
diff --git a/services/backup/blob_client/src/put_client.rs b/services/backup/blob_client/src/put_client.rs
--- a/services/backup/blob_client/src/put_client.rs
+++ b/services/backup/blob_client/src/put_client.rs
@@ -8,10 +8,13 @@
 use proto::PutRequest;
 
 use crate::constants::{BLOB_ADDRESS, MPSC_CHANNEL_BUFFER_CAPACITY};
-use crate::tools::{report_error, check_error};
+use crate::tools::{
+  c_char_pointer_to_string, check_error, report_error, string_to_c_char_pointer,
+};
 use lazy_static::lazy_static;
 use libc;
 use libc::c_char;
+use std::collections::HashMap;
 use std::ffi::CStr;
 use std::sync::{Arc, Mutex};
 use tokio::runtime::Runtime;
@@ -32,17 +35,18 @@
 }
 
 lazy_static! {
-  static ref CLIENT: Arc<Mutex<Option<BidiClient>>> =
-    Arc::new(Mutex::new(None));
-  // todo we should probably create separate clients for different IDs
+  // todo: we should consider limiting the clients size,
+  // if every client is able to allocate up to 4MB data at a time
+  static ref CLIENTS: Arc<Mutex<HashMap<String, BidiClient>>> =
+    Arc::new(Mutex::new(HashMap::new()));
   static ref RUNTIME: Runtime = Runtime::new().unwrap();
   static ref ERROR_MESSAGES: Arc<Mutex<Vec<String>>> =
     Arc::new(Mutex::new(Vec::new()));
 }
 
-fn is_initialized() -> bool {
-  match CLIENT.lock() {
-    Ok(client) => client.is_some(),
+fn is_initialized(holder: &str) -> bool {
+  match CLIENTS.lock() {
+    Ok(clients) => clients.contains_key(holder),
     _ => {
       report_error(&ERROR_MESSAGES, "couldn't access client", Some("put"));
       false
@@ -50,11 +54,17 @@
   }
 }
 
-pub fn put_client_initialize_cxx() -> Result<(), String> {
-  if is_initialized() {
-    put_client_terminate_cxx()?;
+pub fn put_client_initialize_cxx(
+  holder_char: *const c_char,
+) -> Result<(), String> {
+  let holder = c_char_pointer_to_string(holder_char)?;
+  if is_initialized(&holder) {
+    put_client_terminate_cxx(string_to_c_char_pointer(&holder)?)?;
   }
-  assert!(!is_initialized(), "client cannot be initialized twice");
+  assert!(
+    !is_initialized(&holder),
+    "client cannot be initialized twice"
+  );
   // grpc
   if let Ok(mut grpc_client) =
     RUNTIME.block_on(async { BlobServiceClient::connect(BLOB_ADDRESS).await })
@@ -123,10 +133,10 @@
               Ok(maybe_response_message) => {
                 let mut result = false;
                 if let Some(response_message) = maybe_response_message {
-                  // warning: this will produce an error if there's more unread responses than
-                  // MPSC_CHANNEL_BUFFER_CAPACITY
-                  // you should then use put_client_blocking_read_cxx in order to dequeue
-                  // the responses in c++ and make room for more
+                  // warning: this will produce an error if there's more unread 
+                  // responses than MPSC_CHANNEL_BUFFER_CAPACITY
+                  // you should then use put_client_blocking_read_cxx in order
+                  // to dequeue the responses in c++ and make room for more
                   if let Ok(_) = response_thread_tx
                     .try_send((response_message.data_exists as i32).to_string())
                   {
@@ -156,24 +166,35 @@
       };
     });
 
-    if let Ok(mut client) = CLIENT.lock() {
-      *client = Some(BidiClient {
+    if is_initialized(&holder) {
+      return Err(format!(
+        "client initialization overlapped for holder {}",
+        holder
+      ));
+    }
+    if let Ok(mut clients) = CLIENTS.lock() {
+      let client = BidiClient {
         tx: request_thread_tx,
         rx: response_thread_rx,
         rx_handle,
-      });
+      };
+      (*clients).insert(holder, client);
       return Ok(());
     }
-    return Err("could not access client".to_string());
+    return Err(format!("could not access client for holder {}", holder));
   }
   Err("could not successfully connect to the blob server".to_string())
 }
 
-pub fn put_client_blocking_read_cxx() -> Result<String, String> {
+pub fn put_client_blocking_read_cxx(
+  holder_char: *const c_char,
+) -> Result<String, String> {
+  let holder = c_char_pointer_to_string(holder_char)?;
   check_error(&ERROR_MESSAGES)?;
   let response: Option<String> = RUNTIME.block_on(async {
-    if let Ok(mut maybe_client) = CLIENT.lock() {
-      if let Some(mut client) = (*maybe_client).take() {
+    if let Ok(mut clients) = CLIENTS.lock() {
+      let maybe_client = clients.get_mut(&holder);
+      if let Some(client) = maybe_client {
         if let Some(data) = client.rx.recv().await {
           return Some(data);
         } else {
@@ -183,9 +204,8 @@
             Some("put"),
           );
         }
-        *maybe_client = Some(client);
       } else {
-        report_error(&ERROR_MESSAGES, "no client detected", Some("put"));
+        report_error(&ERROR_MESSAGES, "no client detected in blocking read", Some("put"));
       }
     } else {
       report_error(&ERROR_MESSAGES, "couldn't access client", Some("put"));
@@ -203,16 +223,19 @@
  * 3 - data chunk (bytes)
  */
 pub fn put_client_write_cxx(
+  holder_char: *const c_char,
   field_index: usize,
   data: *const c_char,
 ) -> Result<(), String> {
+  let holder = c_char_pointer_to_string(holder_char)?;
   check_error(&ERROR_MESSAGES)?;
   let data_c_str: &CStr = unsafe { CStr::from_ptr(data) };
   let data_bytes: Vec<u8> = data_c_str.to_bytes().to_vec();
 
   RUNTIME.block_on(async {
-    if let Ok(mut maybe_client) = CLIENT.lock() {
-      if let Some(client) = (*maybe_client).take() {
+    if let Ok(clients) = CLIENTS.lock() {
+      let maybe_client = clients.get(&holder);
+      if let Some(client) = maybe_client {
         match client
           .tx
           .send(PutRequestData {
@@ -228,9 +251,8 @@
             Some("put"),
           ),
         }
-        *maybe_client = Some(client);
       } else {
-        report_error(&ERROR_MESSAGES, "no client detected", Some("put"));
+        report_error(&ERROR_MESSAGES, "no client detected in write", Some("put"));
       }
     } else {
       report_error(&ERROR_MESSAGES, "couldn't access client", Some("put"));
@@ -240,15 +262,19 @@
   Ok(())
 }
 
-pub fn put_client_terminate_cxx() -> Result<(), String> {
+pub fn put_client_terminate_cxx(
+  holder_char: *const c_char,
+) -> Result<(), String> {
+  let holder = c_char_pointer_to_string(holder_char)?;
   check_error(&ERROR_MESSAGES)?;
-  if !is_initialized() {
+  if !is_initialized(&holder) {
     check_error(&ERROR_MESSAGES)?;
     return Ok(());
   }
 
-  if let Ok(mut maybe_client) = CLIENT.lock() {
-    if let Some(client) = (*maybe_client).take() {
+  if let Ok(mut clients) = CLIENTS.lock() {
+    let maybe_client = clients.remove(&holder);
+    if let Some(client) = maybe_client {
       drop(client.tx);
       RUNTIME.block_on(async {
         if client.rx_handle.await.is_err() {
@@ -260,14 +286,14 @@
         }
       });
     } else {
-      return Err("no client detected".to_string());
+      return Err("no client detected in terminate".to_string());
     }
   } else {
     return Err("couldn't access client".to_string());
   }
 
   assert!(
-    !is_initialized(),
+    !is_initialized(&holder),
     "client transmitter handler released properly"
   );
   check_error(&ERROR_MESSAGES)?;