diff --git a/backend/src/lib.rs b/backend/src/lib.rs
new file mode 100644
index 0000000..2887c08
--- /dev/null
+++ b/backend/src/lib.rs
@@ -0,0 +1,9 @@
+pub mod api;
+pub mod auth;
+pub mod config;
+pub mod database;
+pub mod errors;
+pub mod middleware;
+pub mod repositories;
+pub mod services;
+pub mod utils;
\ No newline at end of file
diff --git a/backend/src/services/node_manager.rs b/backend/src/services/node_manager.rs
index 2ca781d..c8b8e84 100644
--- a/backend/src/services/node_manager.rs
+++ b/backend/src/services/node_manager.rs
@@ -82,7 +82,7 @@ pub struct LndNode {
 }
 
 /// Parses the node features from the format returned by LND gRPC to LDK NodeFeatures
-fn parse_node_features(features: HashSet<u32>) -> NodeFeatures {
+pub fn parse_node_features(features: HashSet<u32>) -> NodeFeatures {
     let mut flags = vec![0; 256];
 
     for f in features.into_iter() {
diff --git a/backend/src/utils/crypto.rs b/backend/src/utils/crypto.rs
index c2c2d6c..1588a8c 100644
--- a/backend/src/utils/crypto.rs
+++ b/backend/src/utils/crypto.rs
@@ -3,8 +3,10 @@
 //! ## Usage
 //!
 //! ```rust
-//! let encrypted = StringCrypto::encrypt("secret data")?;
-//! let decrypted = StringCrypto::decrypt(&encrypted)?;
+//! use backend::utils::crypto::StringCrypto;
+//! let encrypted = StringCrypto::encrypt("secret data").unwrap();
+//! let decrypted = StringCrypto::decrypt(&encrypted).unwrap();
+//! assert_eq!(decrypted, "secret data");
 //! ```
 
 use crate::config::Config;
diff --git a/backend/src/utils/generate_random_string.rs b/backend/src/utils/generate_random_string.rs
index 6e3b1f8..7e5a21f 100644
--- a/backend/src/utils/generate_random_string.rs
+++ b/backend/src/utils/generate_random_string.rs
@@ -17,6 +17,7 @@ use rand::{Rng, distributions::Alphanumeric};
 /// # Examples
 ///
 /// ```
+/// use backend::utils::generate_random_string::generate_random_string;
 /// let token = generate_random_string(32);
 /// assert_eq!(token.len(), 32);
 ///
diff --git a/backend/src/utils/mod.rs b/backend/src/utils/mod.rs
index b6095f9..38d6ea9 100644
--- a/backend/src/utils/mod.rs
+++ b/backend/src/utils/mod.rs
@@ -306,7 +306,7 @@ pub enum InvoiceStatus {
     Failed,
 }
 
-#[derive(Debug, Serialize, Deserialize, Clone, Default)]
+#[derive(Debug, Serialize, Deserialize, Clone, Default, PartialEq, Eq)]
 pub enum ChannelState {
     Opening, // funding tx not confirmed
     #[default]
diff --git a/backend/src/utils/sats_to_usd.rs b/backend/src/utils/sats_to_usd.rs
index 4a0a680..ad84c99 100644
--- a/backend/src/utils/sats_to_usd.rs
+++ b/backend/src/utils/sats_to_usd.rs
@@ -43,7 +43,7 @@ impl PriceConverter {
         Self::round_to_2_decimals(btc_amount * btc_price)
     }
 
-    fn round_to_2_decimals(value: f64) -> f64 {
+    pub fn round_to_2_decimals(value: f64) -> f64 {
         (value * 100.0).round() / 100.0
     }
 
@@ -71,7 +71,7 @@ impl PriceConverter {
         }
     }
 
-    async fn check_cache(&self) -> Option<f64> {
+    pub async fn check_cache(&self) -> Option<f64> {
         let cache = self.cache.read().await;
         cache.as_ref().and_then(|c| {
             c.last_updated
@@ -99,7 +99,7 @@ impl PriceConverter {
         Ok(price_data.usd)
     }
 
-    async fn update_cache(&self, price: f64) {
+    pub async fn update_cache(&self, price: f64) {
         let mut cache = self.cache.write().await;
         *cache = Some(PriceCache {
             price,
diff --git a/backend/tests/handlers_common_test.rs b/backend/tests/handlers_common_test.rs
new file mode 100644
index 0000000..5074c6e
--- /dev/null
+++ b/backend/tests/handlers_common_test.rs
@@ -0,0 +1,29 @@
+use backend::utils::handlers_common::{parse_payment_hash, parse_public_key};
+use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+
+fn valid_public_key() -> String {
+    let secp = Secp256k1::new();
+    let secret_key = SecretKey::from_slice(&[0xcd; 32]).expect("valid secret key");
+    PublicKey::from_secret_key(&secp, &secret_key).to_string()
+}
+
+const VALID_HASH: &str = "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2";
+
+#[test]
+fn parse_payment_hash_validates_length_and_format() {
+    let (_, body) = parse_payment_hash("a1b2").unwrap_err();
+    assert!(body.contains("invalid_payment_hash_length"));
+
+    let (_, body) = parse_payment_hash("xyz!").unwrap_err();
+    assert!(body.contains("invalid_payment_hash"));
+
+    assert!(parse_payment_hash(VALID_HASH).is_ok());
+}
+
+#[test]
+fn parse_public_key_rejects_invalid_and_accepts_valid() {
+    let (_, body) = parse_public_key("not-a-key").unwrap_err();
+    assert!(body.contains("invalid_public_key"));
+
+    assert!(parse_public_key(&valid_public_key()).is_ok());
+}
\ No newline at end of file
diff --git a/backend/tests/lightning_types_test.rs b/backend/tests/lightning_types_test.rs
new file mode 100644
index 0000000..d931ad2
--- /dev/null
+++ b/backend/tests/lightning_types_test.rs
@@ -0,0 +1,94 @@
+use bitcoin::secp256k1::{PublicKey, Secp256k1, SecretKey};
+use std::str::FromStr;
+
+use backend::utils::*;
+
+fn create_test_pubkey() -> PublicKey {
+    let secp = Secp256k1::new();
+    let secret_key = SecretKey::from_slice(&[0xcd; 32]).unwrap();
+    PublicKey::from_secret_key(&secp, &secret_key)
+}
+
+fn create_alt_test_pubkey() -> PublicKey {
+    let secp = Secp256k1::new();
+    let secret_key = SecretKey::from_slice(&[0xab; 32]).unwrap();
+    PublicKey::from_secret_key(&secp, &secret_key)
+}
+
+#[test]
+fn test_node_id_validation() {
+    let pk = create_test_pubkey();
+    let pk2 = create_alt_test_pubkey();
+    let mut alias = String::from("test_alias");
+
+    // Valid pubkey validation
+    let node_id = NodeId::PublicKey(pk);
+    assert!(node_id.validate(&pk, &mut alias).is_ok());
+
+    // Mismatched pubkey should fail
+    assert!(node_id.validate(&pk2, &mut alias).is_err());
+
+    // Valid alias validation
+    let node_id = NodeId::Alias("test_alias".to_string());
+    assert!(node_id.validate(&pk, &mut alias).is_ok());
+
+    // Mismatched alias should fail
+    alias = String::from("wrong_alias");
+    assert!(node_id.validate(&pk, &mut alias).is_err());
+}
+
+#[test]
+fn test_payment_state_parsing() {
+    // Case-insensitive parsing
+    assert_eq!(
+        PaymentState::from_str("inflight").unwrap(),
+        PaymentState::Inflight
+    );
+    assert_eq!(
+        PaymentState::from_str("FAILED").unwrap(),
+        PaymentState::Failed
+    );
+    assert_eq!(
+        PaymentState::from_str("Settled").unwrap(),
+        PaymentState::Settled
+    );
+
+    // Invalid input should fail
+    assert!(PaymentState::from_str("invalid").is_err());
+}
+
+#[test]
+fn test_payment_type_parsing() {
+    // Case-insensitive parsing
+    assert_eq!(
+        PaymentType::from_str("OUTGOING").unwrap().as_str(),
+        "outgoing"
+    );
+    assert_eq!(
+        PaymentType::from_str("incoming").unwrap().as_str(),
+        "incoming"
+    );
+    assert_eq!(
+        PaymentType::from_str("Forwarded").unwrap().as_str(),
+        "forwarded"
+    );
+
+    // Invalid input should fail
+    assert!(PaymentType::from_str("invalid").is_err());
+}
+
+#[test]
+fn test_channel_state_parsing() {
+    // Case-insensitive parsing
+    assert_eq!(
+        ChannelState::from_str("ACTIVE").unwrap(),
+        ChannelState::Active
+    );
+    assert_eq!(
+        ChannelState::from_str("disabled").unwrap(),
+        ChannelState::Disabled
+    );
+
+    // Invalid input should fail
+    assert!(ChannelState::from_str("invalid").is_err());
+}
diff --git a/backend/tests/node_manager_test.rs b/backend/tests/node_manager_test.rs
new file mode 100644
index 0000000..3b23cda
--- /dev/null
+++ b/backend/tests/node_manager_test.rs
@@ -0,0 +1,30 @@
+use backend::services::node_manager::{parse_channel_point, parse_node_features};
+use std::collections::HashSet;
+use std::str::FromStr;
+use bitcoin::Txid;
+
+#[test]
+fn test_parse_node_features_empty() {
+    let features = HashSet::new();
+    let parsed = parse_node_features(features);
+    assert!(!parsed.supports_basic_mpp());
+    assert!(!parsed.requires_payment_secret());
+}
+
+#[test]
+fn test_parse_channel_point_valid() {
+    let txid = "a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2";
+    let channel_point = format!("{}:1", txid);
+    let result = parse_channel_point(&channel_point).unwrap();
+
+    assert_eq!(result.vout, 1);
+    assert_eq!(result.txid, Txid::from_str(txid).unwrap());
+}
+
+#[test]
+fn test_parse_channel_point_invalid_formats() {
+    assert!(parse_channel_point(":1").is_err());
+    assert!(parse_channel_point("txid:").is_err());
+    assert!(parse_channel_point("txid").is_err());
+    assert!(parse_channel_point("invalid_txid:1").is_err());
+}
\ No newline at end of file
diff --git a/backend/tests/sats_to_usd_test.rs b/backend/tests/sats_to_usd_test.rs
new file mode 100644
index 0000000..326a52c
--- /dev/null
+++ b/backend/tests/sats_to_usd_test.rs
@@ -0,0 +1,39 @@
+use backend::utils::sats_to_usd::PriceConverter;
+
+#[test]
+fn test_sats_to_usd_with_price() {
+    assert_eq!(
+        PriceConverter::sats_to_usd_with_price(100_000_000, 50_000.0),
+        50_000.0
+    );
+    assert_eq!(
+        PriceConverter::sats_to_usd_with_price(50_000_000, 50_000.0),
+        25_000.0
+    );
+    assert_eq!(PriceConverter::sats_to_usd_with_price(1_000, 50_000.0), 0.5);
+    assert_eq!(PriceConverter::sats_to_usd_with_price(0, 50_000.0), 0.0);
+}
+
+#[test]
+fn test_round_to_2_decimals() {
+    assert_eq!(PriceConverter::round_to_2_decimals(123.456), 123.46);
+    assert_eq!(PriceConverter::round_to_2_decimals(123.454), 123.45);
+    assert_eq!(PriceConverter::round_to_2_decimals(99.999), 100.0);
+}
+
+#[tokio::test]
+async fn test_cache_update_and_retrieval() {
+    let converter = PriceConverter::new();
+    converter.update_cache(50_000.0).await;
+
+    assert_eq!(converter.check_cache().await, Some(50_000.0));
+}
+
+#[tokio::test]
+async fn test_sats_to_usd_with_cached_price() {
+    let converter = PriceConverter::new();
+    converter.update_cache(60_000.0).await;
+
+    let result = converter.sats_to_usd(100_000_000).await.unwrap();
+    assert_eq!(result, 60_000.0);
+}
\ No newline at end of file