diff --git a/src/lib.rs b/src/lib.rs
index faa7ce2..486b59a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,7 +2,11 @@ use serde::{Deserialize, Serialize};
 use std::error::Error;
 use std::fmt;
 
-const URL_COMPLETION: &str = "https://api.openai.com/v1/chat/completions";
+const DEFAULT_URL_COMPLETION: &str = "https://api.openai.com/v1/chat/completions";
+
+fn default_url_completion() -> String {
+    DEFAULT_URL_COMPLETION.to_string()
+}
 
 #[derive(Debug, Deserialize, Serialize)]
 struct Config {
@@ -13,6 +17,8 @@ struct Config {
 struct OpenAI {
     model: String,
     access_key: String,
+    #[serde(default = "default_url_completion")]
+    url_completion: String,
 }
 
 #[derive(Debug, Deserialize, Serialize)]
@@ -117,7 +123,7 @@ impl Gptcli {
 
         let client = reqwest::blocking::Client::new();
         let res = client
-            .post(URL_COMPLETION)
+            .post(&self.config.openai.url_completion)
             .header(
                 "Authorization",
                 format!("Bearer {}", self.config.openai.access_key),
@@ -138,3 +144,31 @@ impl Gptcli {
         Ok(res)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::{Config, default_url_completion};
+
+    #[test]
+    fn parse_config_with_custom_url() {
+        let toml_str = r#"
+        [openai]
+        model = "gpt-3.5-turbo"
+        access_key = "key"
+        url_completion = "http://example.com"
+        "#;
+        let config: Config = toml::from_str(toml_str).unwrap();
+        assert_eq!(config.openai.url_completion, "http://example.com");
+    }
+
+    #[test]
+    fn parse_config_without_url_uses_default() {
+        let toml_str = r#"
+        [openai]
+        model = "gpt-3.5-turbo"
+        access_key = "key"
+        "#;
+        let config: Config = toml::from_str(toml_str).unwrap();
+        assert_eq!(config.openai.url_completion, default_url_completion());
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index 05a2cdc..9ab2060 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,7 +5,11 @@ use std::io::Write;
 
 fn get_config_path() -> String {
     let homepath = home_dir().unwrap();
-    format!("{}/.gptcli.toml", homepath.as_path().to_str().unwrap())
+    homepath
+        .join(".gptcli.toml")
+        .to_str()
+        .unwrap()
+        .to_string()
 }
 
 fn main() {
@@ -35,3 +39,26 @@ fn main() {
         println!("\n{}{}", message, choice.message.content);
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::get_config_path;
+    use std::env;
+    use std::path::PathBuf;
+
+    #[test]
+    fn config_path_uses_home_directory() {
+        let original = env::var("HOME").ok();
+        let temp_home = env::temp_dir().join("gptcli_test_home");
+        env::set_var("HOME", &temp_home);
+
+        let path = get_config_path();
+        assert_eq!(PathBuf::from(path), temp_home.join(".gptcli.toml"));
+
+        if let Some(val) = original {
+            env::set_var("HOME", val);
+        } else {
+            env::remove_var("HOME");
+        }
+    }
+}