diff --git a/wasm/src/results.rs b/wasm/src/results.rs
index 9be3faa..ba7389d 100644
--- a/wasm/src/results.rs
+++ b/wasm/src/results.rs
@@ -70,3 +70,24 @@ impl From<Result<Vec<Certificate>, ServiceError>> for AllCertsResult {
         }
     }
 }
+
+#[fce]
+pub struct AddRootResult {
+    pub ret_code: u32,
+    pub error: String,
+}
+
+impl From<Result<(), ServiceError>> for AddRootResult {
+    fn from(result: Result<(), ServiceError>) -> Self {
+        match result {
+            Ok(()) => AddRootResult {
+                ret_code: 0,
+                error: "".to_string(),
+            },
+            Err(e) => AddRootResult {
+                ret_code: 1,
+                error: format!("{}", e),
+            },
+        }
+    }
+}
diff --git a/wasm/src/service_api.rs b/wasm/src/service_api.rs
index c34bce1..db44775 100644
--- a/wasm/src/service_api.rs
+++ b/wasm/src/service_api.rs
@@ -1,9 +1,9 @@
 use crate::dto::Certificate;
-use crate::results::{AllCertsResult, InsertResult, WeightResult};
+use crate::results::{AddRootResult, AllCertsResult, InsertResult, WeightResult};
 use crate::service_impl::{
-    get_all_certs_impl, get_weight_impl, insert_cert_impl, insert_cert_impl_raw,
+    add_root_impl, get_all_certs_impl, get_weight_impl, insert_cert_impl, insert_cert_impl_raw,
 };
-use fluence::fce;
+use fluence::{fce, CallParameters};
 
 #[fce]
 /// add a certificate in string representation to trust graph if it is valid
@@ -30,6 +30,21 @@ fn get_all_certs(issued_for: String) -> AllCertsResult {
     get_all_certs_impl(issued_for).into()
 }
 
+#[fce]
+/// could add only a host of a trust graph service
+fn add_root(pk: String, weight: u32) -> AddRootResult {
+    let call_parameters: CallParameters = fluence::get_call_parameters();
+    let init_peer_id = call_parameters.init_peer_id.clone();
+    if call_parameters.host_id == init_peer_id {
+        add_root_impl(pk, weight).into()
+    } else {
+        return AddRootResult {
+            ret_code: 1,
+            error: "Root could add only a host of trust graph service",
+        };
+    }
+}
+
 // TODO rewrite test after #[fce_test] will be implemented
 // #[fce]
 // fn test() -> String {
diff --git a/wasm/src/service_impl.rs b/wasm/src/service_impl.rs
index 4d2007a..034c857 100644
--- a/wasm/src/service_impl.rs
+++ b/wasm/src/service_impl.rs
@@ -6,7 +6,7 @@ use std::convert::{Into, TryInto};
 use std::str::FromStr;
 use std::time::Duration;
 use thiserror::Error as ThisError;
-use trust_graph::{CertificateError, TrustGraphError};
+use trust_graph::{CertificateError, PublicKeyHashable, TrustGraphError};
 
 #[derive(ThisError, Debug)]
 pub enum ServiceError {
@@ -61,3 +61,10 @@ pub fn insert_cert_impl(certificate: Certificate, duration: u64) -> Result<(), S
     add_cert(certificate, duration)?;
     Ok(())
 }
+
+pub fn add_root_impl(pk: String, weight: u32) -> Result<(), ServiceError> {
+    let mut tg = get_data().lock();
+    let pk = PublicKey::from_base58(&pk)?.into();
+    tg.add_root_weight(pk, weight)?;
+    Ok(())
+}