diff --git a/src/connector/src/lib.rs b/src/connector/src/lib.rs
index 59dbd0969bbfb..c5d8bd79df454 100644
--- a/src/connector/src/lib.rs
+++ b/src/connector/src/lib.rs
@@ -61,6 +61,19 @@ impl ConnectorParams {
     }
 }
 
+pub(crate) fn deserialize_u32_from_string<'de, D>(deserializer: D) -> Result<u32, D::Error>
+where
+    D: de::Deserializer<'de>,
+{
+    let s: String = de::Deserialize::deserialize(deserializer)?;
+    s.parse().map_err(|_| {
+        de::Error::invalid_value(
+            de::Unexpected::Str(&s),
+            &"integer greater than or equal to 0",
+        )
+    })
+}
+
 pub(crate) fn deserialize_bool_from_string<'de, D>(deserializer: D) -> Result<bool, D::Error>
 where
     D: de::Deserializer<'de>,
diff --git a/src/connector/src/sink/kafka.rs b/src/connector/src/sink/kafka.rs
index 5e44e8c0bea8c..968821c6b4dcd 100644
--- a/src/connector/src/sink/kafka.rs
+++ b/src/connector/src/sink/kafka.rs
@@ -35,7 +35,9 @@ use super::{
 };
 use crate::common::KafkaCommon;
 use crate::sink::{datum_to_json_object, record_to_json, Result};
-use crate::{deserialize_bool_from_string, deserialize_duration_from_string};
+use crate::{
+    deserialize_bool_from_string, deserialize_duration_from_string, deserialize_u32_from_string,
+};
 
 pub const KAFKA_SINK: &str = "kafka";
 
@@ -55,6 +57,10 @@ const fn _default_use_transaction() -> bool {
     true
 }
 
+const fn _default_force_append_only() -> bool {
+    false
+}
+
 #[derive(Debug, Clone, Deserialize)]
 #[serde(deny_unknown_fields)]
 pub struct KafkaConfig {
@@ -66,8 +72,11 @@ pub struct KafkaConfig {
 
     pub r#type: String, // accept "append-only", "debezium", or "upsert"
 
-    #[serde(default)]
-    pub force_append_only: Option<bool>,
+    #[serde(
+        default = "_default_force_append_only",
+        deserialize_with = "deserialize_bool_from_string"
+    )]
+    pub force_append_only: bool,
 
     pub identifier: String,
 
@@ -78,7 +87,11 @@ pub struct KafkaConfig {
     )]
     pub timeout: Duration,
 
-    #[serde(rename = "properties.retry.max", default = "_default_max_retries")]
+    #[serde(
+        rename = "properties.retry.max",
+        default = "_default_max_retries",
+        deserialize_with = "deserialize_u32_from_string"
+    )]
     pub max_retry_num: u32,
 
     #[serde(
@@ -89,8 +102,8 @@ pub struct KafkaConfig {
     pub retry_interval: Duration,
 
     #[serde(
-        deserialize_with = "deserialize_bool_from_string",
-        default = "_default_use_transaction"
+        default = "_default_use_transaction",
+        deserialize_with = "deserialize_bool_from_string"
     )]
     pub use_transaction: bool,
 }
@@ -565,17 +578,74 @@ mod test {
             "properties.bootstrap.server".to_string() => "localhost:9092".to_string(),
             "topic".to_string() => "test".to_string(),
             "type".to_string() => "append-only".to_string(),
+            "force_append_only".to_string() => "true".to_string(),
             "use_transaction".to_string() => "False".to_string(),
             "properties.security.protocol".to_string() => "SASL".to_string(),
             "properties.sasl.mechanism".to_string() => "SASL".to_string(),
             "properties.sasl.username".to_string() => "test".to_string(),
             "properties.sasl.password".to_string() => "test".to_string(),
             "identifier".to_string() => "test_sink_1".to_string(),
-            "properties.timeout".to_string() => "5s".to_string(),
+            "properties.timeout".to_string() => "10s".to_string(),
+            "properties.retry.max".to_string() => "20".to_string(),
+            "properties.retry.interval".to_string() => "500ms".to_string(),
         };
-
         let config = KafkaConfig::from_hashmap(properties).unwrap();
-        println!("{:?}", config);
+        assert_eq!(config.common.brokers, "localhost:9092");
+        assert_eq!(config.common.topic, "test");
+        assert_eq!(config.r#type, "append-only");
+        assert!(config.force_append_only);
+        assert!(!config.use_transaction);
+        assert_eq!(config.timeout, Duration::from_secs(10));
+        assert_eq!(config.max_retry_num, 20);
+        assert_eq!(config.retry_interval, Duration::from_millis(500));
+
+        // Optional fields eliminated.
+        let properties: HashMap<String, String> = hashmap! {
+            "connector".to_string() => "kafka".to_string(),
+            "properties.bootstrap.server".to_string() => "localhost:9092".to_string(),
+            "topic".to_string() => "test".to_string(),
+            "type".to_string() => "upsert".to_string(),
+            "identifier".to_string() => "test_sink_2".to_string(),
+        };
+        let config = KafkaConfig::from_hashmap(properties).unwrap();
+        assert!(!config.force_append_only);
+        assert!(config.use_transaction);
+        assert_eq!(config.timeout, Duration::from_secs(5));
+        assert_eq!(config.max_retry_num, 3);
+        assert_eq!(config.retry_interval, Duration::from_millis(100));
+
+        // Invalid u32 input.
+        let properties: HashMap<String, String> = hashmap! {
+            "connector".to_string() => "kafka".to_string(),
+            "properties.bootstrap.server".to_string() => "localhost:9092".to_string(),
+            "topic".to_string() => "test".to_string(),
+            "type".to_string() => "upsert".to_string(),
+            "identifier".to_string() => "test_sink_3".to_string(),
+            "properties.retry.max".to_string() => "-20".to_string(),  // error!
+        };
+        assert!(KafkaConfig::from_hashmap(properties).is_err());
+
+        // Invalid bool input.
+        let properties: HashMap<String, String> = hashmap! {
+            "connector".to_string() => "kafka".to_string(),
+            "properties.bootstrap.server".to_string() => "localhost:9092".to_string(),
+            "topic".to_string() => "test".to_string(),
+            "type".to_string() => "upsert".to_string(),
+            "identifier".to_string() => "test_sink_4".to_string(),
+            "force_append_only".to_string() => "yes".to_string(),  // error!
+        };
+        assert!(KafkaConfig::from_hashmap(properties).is_err());
+
+        // Invalid duration input.
+        let properties: HashMap<String, String> = hashmap! {
+            "connector".to_string() => "kafka".to_string(),
+            "properties.bootstrap.server".to_string() => "localhost:9092".to_string(),
+            "topic".to_string() => "test".to_string(),
+            "type".to_string() => "upsert".to_string(),
+            "identifier".to_string() => "test_sink_5".to_string(),
+            "properties.retry.interval".to_string() => "500minutes".to_string(),  // error!
+        };
+        assert!(KafkaConfig::from_hashmap(properties).is_err());
     }
 
     #[ignore]