diff --git a/src/stratum-api-s3/src/endpoint/definitions.rs b/src/stratum-api-s3/src/endpoint/definitions.rs
index e69de29..73d2c2b 100644
--- a/src/stratum-api-s3/src/endpoint/definitions.rs
+++ b/src/stratum-api-s3/src/endpoint/definitions.rs
@@ -0,0 +1,53 @@
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Endpoint {
+    // Service level
+    ListBuckets,
+
+    // Bucket level
+    CreateBucket,
+    DeleteBucket,
+    HeadBucket,
+    ListObjectsV2 {
+        delimiter: Option<String>,
+        prefix: Option<String>,
+        max_keys: Option<usize>,
+        continuation_token: Option<String>,
+    },
+
+    // Object level
+    GetObject {
+        key: String,
+        version_id: Option<String>,
+        part_number: Option<u64>,
+    },
+    PutObject {
+        key: String,
+    },
+    DeleteObject {
+        key: String,
+        version_id: Option<String>,
+    },
+    HeadObject {
+        key: String,
+        version_id: Option<String>,
+        part_number: Option<u64>,
+    },
+
+    // Multipart
+    CreateMultipartUpload {
+        key: String,
+    },
+    UploadPart {
+        key: String,
+        part_number: u64,
+        upload_id: String,
+    },
+    CompleteMultipartUpload {
+        key: String,
+        upload_id: String,
+    },
+    AbortMultipartUpload {
+        key: String,
+        upload_id: String,
+    },
+}
\ No newline at end of file
diff --git a/src/stratum-api-s3/src/endpoint/mod.rs b/src/stratum-api-s3/src/endpoint/mod.rs
index 1eb199d..d142ee9 100644
--- a/src/stratum-api-s3/src/endpoint/mod.rs
+++ b/src/stratum-api-s3/src/endpoint/mod.rs
@@ -1,3 +1,5 @@
 mod definitions;
 mod parser;
 
+pub use definitions::Endpoint;
+
diff --git a/src/stratum-api-s3/src/endpoint/parser.rs b/src/stratum-api-s3/src/endpoint/parser.rs
index 7bf4cd7..c469934 100644
--- a/src/stratum-api-s3/src/endpoint/parser.rs
+++ b/src/stratum-api-s3/src/endpoint/parser.rs
@@ -1,3 +1,271 @@
 use std::collections::HashMap;
 use hyper::Method;
-use super::definitions::
\ No newline at end of file
+use super::definitions::Endpoint;
+use crate::errors::ApiError;
+
+
+pub fn parse_endpoint(
+    method: &Method,
+    path: &str,
+    query: &HashMap<String, String>,
+) -> Result<Endpoint, ApiError> {
+    let segments: Vec<&str> = path
+        .trim_start_matches('/')
+        .splitn(2, '/')
+        .collect();
+
+    let bucket = segments.get(0).copied().unwrap_or("");
+    let key = segments.get(1).copied().unwrap_or("");
+
+    match (method, bucket, key) {
+        // Service level
+        (&Method::GET, "", "") => Ok(Endpoint::ListBuckets),
+
+        // Bucket level
+        (&Method::PUT, b, "") if !b.is_empty() => Ok(Endpoint::CreateBucket),
+        (&Method::DELETE, b, "") if !b.is_empty() => Ok(Endpoint::DeleteBucket),
+        (&Method::HEAD, b, "") if !b.is_empty() => Ok(Endpoint::HeadBucket),
+        (&Method::GET, b, "") if !b.is_empty() => Ok(Endpoint::ListObjectsV2 {
+            delimiter: query.get("delimiter").cloned(),
+            prefix: query.get("prefix").cloned(),
+            max_keys: query.get("max-keys")
+                .and_then(|v| v.parse().ok()),
+            continuation_token: query.get("continuation-token").cloned(),
+        }),
+
+        // Object level
+        (&Method::GET, _, k) if !k.is_empty() => Ok(Endpoint::GetObject {
+            key: k.to_string(),
+            version_id: query.get("versionId").cloned(),
+            part_number: query.get("partNumber")
+                .and_then(|v| v.parse().ok()),
+        }),
+        (&Method::PUT, _, k) if !k.is_empty() => {
+            // distinguish UploadPart from PutObject
+            if let Some(upload_id) = query.get("uploadId") {
+                Ok(Endpoint::UploadPart {
+                    key: k.to_string(),
+                    upload_id: upload_id.clone(),
+                    part_number: query.get("partNumber")
+                        .and_then(|v| v.parse().ok())
+                        .ok_or(ApiError::InvalidArgument("missing partNumber".into()))?,
+                })
+            } else {
+                Ok(Endpoint::PutObject {
+                    key: k.to_string(),
+                })
+            }
+        },
+        (&Method::DELETE, _, k) if !k.is_empty() => {
+            if let Some(upload_id) = query.get("uploadId") {
+                Ok(Endpoint::AbortMultipartUpload {
+                    key: k.to_string(),
+                    upload_id: upload_id.clone(),
+                })
+            } else {
+                Ok(Endpoint::DeleteObject {
+                    key: k.to_string(),
+                    version_id: query.get("versionId").cloned(),
+                })
+            }
+        },
+        (&Method::HEAD, _, k) if !k.is_empty() => Ok(Endpoint::HeadObject {
+            key: k.to_string(),
+            version_id: query.get("versionId").cloned(),
+            part_number: query.get("partNumber")
+                .and_then(|v| v.parse().ok()),
+        }),
+        (&Method::POST, _, k) if !k.is_empty() => {
+            if query.contains_key("uploads") {
+                Ok(Endpoint::CreateMultipartUpload {
+                    key: k.to_string(),
+                })
+            } else if let Some(upload_id) = query.get("uploadId") {
+                Ok(Endpoint::CompleteMultipartUpload {
+                    key: k.to_string(),
+                    upload_id: upload_id.clone(),
+                })
+            } else {
+                Err(ApiError::InvalidArgument("unknown POST operation".into()))
+            }
+        },
+
+        _ => Err(ApiError::InvalidArgument(
+            format!("unknown endpoint: {} {}", method, path)
+        )),
+    }
+}
+
+// src/stratum-api-s3/src/endpoint/parser.rs
+
+// ... your existing parse_endpoint function ...
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use hyper::Method;
+    use std::collections::HashMap;
+
+    fn empty_query() -> HashMap<String, String> {
+        HashMap::new()
+    }
+
+    fn query(pairs: &[(&str, &str)]) -> HashMap<String, String> {
+        pairs.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect()
+    }
+
+    // Service level
+    #[test]
+    fn test_list_buckets() {
+        let result = parse_endpoint(&Method::GET, "/", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::ListBuckets);
+    }
+
+    // Bucket level
+    #[test]
+    fn test_create_bucket() {
+        let result = parse_endpoint(&Method::PUT, "/my-bucket", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::CreateBucket);
+    }
+
+    #[test]
+    fn test_delete_bucket() {
+        let result = parse_endpoint(&Method::DELETE, "/my-bucket", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::DeleteBucket);
+    }
+
+    #[test]
+    fn test_head_bucket() {
+        let result = parse_endpoint(&Method::HEAD, "/my-bucket", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::HeadBucket);
+    }
+
+    #[test]
+    fn test_list_objects_v2_empty() {
+        let result = parse_endpoint(&Method::GET, "/my-bucket", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::ListObjectsV2 {
+            delimiter: None,
+            prefix: None,
+            max_keys: None,
+            continuation_token: None,
+        });
+    }
+
+    #[test]
+    fn test_list_objects_v2_with_prefix() {
+        let q = query(&[("prefix", "photos/"), ("max-keys", "100")]);
+        let result = parse_endpoint(&Method::GET, "/my-bucket", &q);
+        assert_eq!(result.unwrap(), Endpoint::ListObjectsV2 {
+            delimiter: None,
+            prefix: Some("photos/".to_string()),
+            max_keys: Some(100),
+            continuation_token: None,
+        });
+    }
+
+    // Object level
+    #[test]
+    fn test_get_object() {
+        let result = parse_endpoint(&Method::GET, "/my-bucket/photo.jpg", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::GetObject {
+            key: "photo.jpg".to_string(),
+            version_id: None,
+            part_number: None,
+        });
+    }
+
+    #[test]
+    fn test_get_object_nested_key() {
+        let result = parse_endpoint(&Method::GET, "/my-bucket/photos/2024/beach.jpg", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::GetObject {
+            key: "photos/2024/beach.jpg".to_string(), // full path preserved
+            version_id: None,
+            part_number: None,
+        });
+    }
+
+    #[test]
+    fn test_put_object() {
+        let result = parse_endpoint(&Method::PUT, "/my-bucket/photo.jpg", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::PutObject {
+            key: "photo.jpg".to_string(),
+        });
+    }
+
+    #[test]
+    fn test_delete_object() {
+        let result = parse_endpoint(&Method::DELETE, "/my-bucket/photo.jpg", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::DeleteObject {
+            key: "photo.jpg".to_string(),
+            version_id: None,
+        });
+    }
+
+    #[test]
+    fn test_delete_object_with_version() {
+        let q = query(&[("versionId", "abc123")]);
+        let result = parse_endpoint(&Method::DELETE, "/my-bucket/photo.jpg", &q);
+        assert_eq!(result.unwrap(), Endpoint::DeleteObject {
+            key: "photo.jpg".to_string(),
+            version_id: Some("abc123".to_string()),
+        });
+    }
+
+    #[test]
+    fn test_head_object() {
+        let result = parse_endpoint(&Method::HEAD, "/my-bucket/photo.jpg", &empty_query());
+        assert_eq!(result.unwrap(), Endpoint::HeadObject {
+            key: "photo.jpg".to_string(),
+            version_id: None,
+            part_number: None,
+        });
+    }
+
+    // Multipart
+    #[test]
+    fn test_create_multipart_upload() {
+        let q = query(&[("uploads", "")]);
+        let result = parse_endpoint(&Method::POST, "/my-bucket/video.mp4", &q);
+        assert_eq!(result.unwrap(), Endpoint::CreateMultipartUpload {
+            key: "video.mp4".to_string(),
+        });
+    }
+
+    #[test]
+    fn test_upload_part() {
+        let q = query(&[("partNumber", "1"), ("uploadId", "abc123")]);
+        let result = parse_endpoint(&Method::PUT, "/my-bucket/video.mp4", &q);
+        assert_eq!(result.unwrap(), Endpoint::UploadPart {
+            key: "video.mp4".to_string(),
+            part_number: 1,
+            upload_id: "abc123".to_string(),
+        });
+    }
+
+    #[test]
+    fn test_complete_multipart_upload() {
+        let q = query(&[("uploadId", "abc123")]);
+        let result = parse_endpoint(&Method::POST, "/my-bucket/video.mp4", &q);
+        assert_eq!(result.unwrap(), Endpoint::CompleteMultipartUpload {
+            key: "video.mp4".to_string(),
+            upload_id: "abc123".to_string(),
+        });
+    }
+
+    #[test]
+    fn test_abort_multipart_upload() {
+        let q = query(&[("uploadId", "abc123")]);
+        let result = parse_endpoint(&Method::DELETE, "/my-bucket/video.mp4", &q);
+        assert_eq!(result.unwrap(), Endpoint::AbortMultipartUpload {
+            key: "video.mp4".to_string(),
+            upload_id: "abc123".to_string(),
+        });
+    }
+
+    // Error cases
+    #[test]
+    fn test_unknown_endpoint_returns_error() {
+        let result = parse_endpoint(&Method::PATCH, "/my-bucket/photo.jpg", &empty_query());
+        assert!(result.is_err());
+    }
+}
\ No newline at end of file
diff --git a/src/stratum-api-s3/src/errors/mod.rs b/src/stratum-api-s3/src/errors/mod.rs
index d4a42f7..3853b4f 100644
--- a/src/stratum-api-s3/src/errors/mod.rs
+++ b/src/stratum-api-s3/src/errors/mod.rs
@@ -1 +1,3 @@
 mod error;
+
+pub use error::ApiError;
diff --git a/src/stratum-api-s3/src/lib.rs b/src/stratum-api-s3/src/lib.rs
index 152f7ef..6e498b7 100644
--- a/src/stratum-api-s3/src/lib.rs
+++ b/src/stratum-api-s3/src/lib.rs
@@ -1,3 +1,4 @@
 pub mod endpoint;
-pub mod common;
-pub mod errors;
\ No newline at end of file
+pub mod errors;
+
+pub use endpoint::Endpoint;
\ No newline at end of file