diff --git a/Cargo.lock b/Cargo.lock
index fe57c084db..9e9b41c19e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5111,6 +5111,7 @@ checksum = "2932dc07acd2066ff2e3921a4419606b220ba6cd03a9935123856cc534877056"
 dependencies = [
  "rand 0.6.5",
  "secp256k1-sys 0.1.2",
+ "serde",
 ]
 
 [[package]]
@@ -5120,7 +5121,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6179428c22c73ac0fbb7b5579a56353ce78ba29759b3b8575183336ea74cdfb"
 dependencies = [
  "secp256k1-sys 0.3.0",
- "serde",
 ]
 
 [[package]]
@@ -5279,7 +5279,7 @@ dependencies = [
 [[package]]
 name = "serial_test"
 version = "0.5.1"
-source = "git+https://github.com/tworec/serial_test.git?branch=actix_rt_test#0d3db75eb5dde6aae32ba3672c80af652e0b58ba"
+source = "git+https://github.com/tworec/serial_test.git?branch=actix_rt_test#6c848541e89262f90ca693d9e1a84c6f3df0953b"
 dependencies = [
  "lazy_static",
  "parking_lot 0.10.2",
@@ -5300,7 +5300,7 @@ dependencies = [
 [[package]]
 name = "serial_test_derive"
 version = "0.5.1"
-source = "git+https://github.com/tworec/serial_test.git?branch=actix_rt_test#0d3db75eb5dde6aae32ba3672c80af652e0b58ba"
+source = "git+https://github.com/tworec/serial_test.git?branch=actix_rt_test#6c848541e89262f90ca693d9e1a84c6f3df0953b"
 dependencies = [
  "proc-macro2 1.0.24",
  "quote 1.0.7",
@@ -6855,7 +6855,7 @@ dependencies = [
 [[package]]
 name = "ya-client"
 version = "0.4.0"
-source = "git+https://github.com/golemfactory/ya-client.git?branch=event-api/master#ff0a2d48f0b8b2e6b751cc536db0edc378af8ed7"
+source = "git+https://github.com/golemfactory/ya-client.git?branch=event-api/master#721259d017a3306af3724eb393aa2f9383d74b9c"
 dependencies = [
  "awc 1.0.1",
  "bytes 0.5.6",
@@ -6892,7 +6892,7 @@ dependencies = [
 [[package]]
 name = "ya-client-model"
 version = "0.2.0"
-source = "git+https://github.com/golemfactory/ya-client.git?branch=event-api/master#ff0a2d48f0b8b2e6b751cc536db0edc378af8ed7"
+source = "git+https://github.com/golemfactory/ya-client.git?branch=event-api/master#721259d017a3306af3724eb393aa2f9383d74b9c"
 dependencies = [
  "bigdecimal 0.1.2",
  "chrono",
@@ -6901,9 +6901,11 @@ dependencies = [
  "hex",
  "openssl",
  "rand 0.7.3",
- "secp256k1 0.19.0",
+ "secp256k1 0.17.2",
  "serde",
  "serde_json",
+ "strum",
+ "strum_macros",
  "thiserror",
 ]
 
diff --git a/core/payment/src/dao/debit_note_event.rs b/core/payment/src/dao/debit_note_event.rs
index 783823e74b..a535cdbf4c 100644
--- a/core/payment/src/dao/debit_note_event.rs
+++ b/core/payment/src/dao/debit_note_event.rs
@@ -37,19 +37,15 @@ impl<'c> AsDao<'c> for DebitNoteEventDao<'c> {
 }
 
 impl<'c> DebitNoteEventDao<'c> {
-    pub async fn create<T: Serialize>(
+    pub async fn create<T: Serialize + Send + 'static>(
         &self,
         debit_note_id: String,
         owner_id: NodeId,
         event_type: DebitNoteEventType,
         details: Option<T>,
     ) -> DbResult<()> {
-        let event = WriteObj::new(debit_note_id, owner_id, event_type, details)?;
         do_with_transaction(self.pool, move |conn| {
-            diesel::insert_into(write_dsl::pay_debit_note_event)
-                .values(event)
-                .execute(conn)?;
-            Ok(())
+            create(debit_note_id, owner_id, event_type, details, conn)
         })
         .await
     }
diff --git a/core/payment/src/dao/invoice_event.rs b/core/payment/src/dao/invoice_event.rs
index 7fc04d1490..366dc4beca 100644
--- a/core/payment/src/dao/invoice_event.rs
+++ b/core/payment/src/dao/invoice_event.rs
@@ -37,19 +37,15 @@ impl<'c> AsDao<'c> for InvoiceEventDao<'c> {
 }
 
 impl<'c> InvoiceEventDao<'c> {
-    pub async fn create<T: Serialize>(
+    pub async fn create<T: Serialize + Send + 'static>(
         &self,
         invoice_id: String,
         owner_id: NodeId,
         event_type: InvoiceEventType,
         details: Option<T>,
     ) -> DbResult<()> {
-        let event = WriteObj::new(invoice_id, owner_id, event_type, details)?;
         do_with_transaction(self.pool, move |conn| {
-            diesel::insert_into(write_dsl::pay_invoice_event)
-                .values(event)
-                .execute(conn)?;
-            Ok(())
+            create(invoice_id, owner_id, event_type, details, conn)
         })
         .await
     }
diff --git a/core/payment/src/models/debit_note_event.rs b/core/payment/src/models/debit_note_event.rs
index 9244f4ca87..8db7783969 100644
--- a/core/payment/src/models/debit_note_event.rs
+++ b/core/payment/src/models/debit_note_event.rs
@@ -31,7 +31,7 @@ impl WriteObj {
         Ok(Self {
             debit_note_id,
             owner_id,
-            event_type: serde_json::to_string(&event_type)?,
+            event_type: event_type.to_string(),
             details,
         })
     }
@@ -53,6 +53,12 @@ impl TryFrom<ReadObj> for DebitNoteEvent {
     type Error = DbError;
 
     fn try_from(event: ReadObj) -> DbResult<Self> {
+        let event_type = event.event_type.parse().map_err(|e| {
+            DbError::Integrity(format!(
+                "DebitNoteEvent type `{}` parsing failed: {}",
+                &event.event_type, e
+            ))
+        })?;
         // TODO Attach details when event_type=REJECTED
         let _details = match event.details {
             Some(s) => Some(json_from_str(&s)?),
@@ -61,7 +67,7 @@ impl TryFrom<ReadObj> for DebitNoteEvent {
         Ok(Self {
             debit_note_id: event.debit_note_id,
             event_date: Utc.from_utc_datetime(&event.timestamp),
-            event_type: serde_json::from_str(&event.event_type)?,
+            event_type,
         })
     }
 }
diff --git a/core/payment/src/models/invoice_event.rs b/core/payment/src/models/invoice_event.rs
index e7870ce1bb..6060cad717 100644
--- a/core/payment/src/models/invoice_event.rs
+++ b/core/payment/src/models/invoice_event.rs
@@ -31,7 +31,7 @@ impl WriteObj {
         Ok(Self {
             invoice_id,
             owner_id,
-            event_type: serde_json::to_string(&event_type)?,
+            event_type: event_type.to_string(),
             details,
         })
     }
@@ -53,12 +53,19 @@ impl TryFrom<ReadObj> for InvoiceEvent {
     type Error = DbError;
 
     fn try_from(event: ReadObj) -> DbResult<Self> {
+        let event_type = event.event_type.parse().map_err(|e| {
+            DbError::Integrity(format!(
+                "InvoiceEvent type `{}` parsing failed: {}",
+                event.event_type, e
+            ))
+        })?;
+
         // TODO Attach details when event_type=REJECTED
         let _details = match event.details {
             Some(s) => Some(json_from_str(&s)?),
             None => None,
         };
-        let event_type = serde_json::from_str(&event.event_type)?;
+
         Ok(Self {
             invoice_id: event.invoice_id,
             event_date: Utc.from_utc_datetime(&event.timestamp),