diff --git a/aitbc/__init__.py b/aitbc/__init__.py
index 26194c9d..95762d33 100644
--- a/aitbc/__init__.py
+++ b/aitbc/__init__.py
@@ -38,8 +38,31 @@ from .env import (
     get_float_env_var,
     get_list_env_var,
 )
+from .paths import (
+    get_data_path,
+    get_config_path,
+    get_log_path,
+    get_repo_path,
+    ensure_dir,
+    ensure_file_dir,
+    resolve_path,
+    get_keystore_path,
+    get_blockchain_data_path,
+    get_marketplace_data_path,
+)
+from .json_utils import (
+    load_json,
+    save_json,
+    merge_json,
+    json_to_string,
+    string_to_json,
+    get_nested_value,
+    set_nested_value,
+    flatten_json,
+)
+from .http_client import AITBCHTTPClient
 
-__version__ = "0.3.0"
+__version__ = "0.4.0"
 __all__ = [
     # Logging
     "get_logger",
@@ -75,4 +98,26 @@ __all__ = [
     "get_int_env_var",
     "get_float_env_var",
     "get_list_env_var",
+    # Path utilities
+    "get_data_path",
+    "get_config_path",
+    "get_log_path",
+    "get_repo_path",
+    "ensure_dir",
+    "ensure_file_dir",
+    "resolve_path",
+    "get_keystore_path",
+    "get_blockchain_data_path",
+    "get_marketplace_data_path",
+    # JSON utilities
+    "load_json",
+    "save_json",
+    "merge_json",
+    "json_to_string",
+    "string_to_json",
+    "get_nested_value",
+    "set_nested_value",
+    "flatten_json",
+    # HTTP client
+    "AITBCHTTPClient",
 ]
diff --git a/aitbc/http_client.py b/aitbc/http_client.py
new file mode 100644
index 00000000..0e9b521c
--- /dev/null
+++ b/aitbc/http_client.py
@@ -0,0 +1,207 @@
+"""
+AITBC HTTP Client
+Base HTTP client with common utilities for AITBC applications
+"""
+
+import requests
+from typing import Dict, Any, Optional, Union
+from .exceptions import NetworkError
+
+
+class AITBCHTTPClient:
+    """
+    Base HTTP client for AITBC applications.
+    Provides common HTTP methods with error handling.
+    """
+    
+    def __init__(
+        self,
+        base_url: str = "",
+        timeout: int = 30,
+        headers: Optional[Dict[str, str]] = None
+    ):
+        """
+        Initialize HTTP client.
+        
+        Args:
+            base_url: Base URL for all requests
+            timeout: Request timeout in seconds
+            headers: Default headers for all requests
+        """
+        self.base_url = base_url.rstrip("/")
+        self.timeout = timeout
+        self.headers = headers or {}
+        self.session = requests.Session()
+        self.session.headers.update(self.headers)
+    
+    def _build_url(self, endpoint: str) -> str:
+        """
+        Build full URL from base URL and endpoint.
+        
+        Args:
+            endpoint: API endpoint
+            
+        Returns:
+            Full URL
+        """
+        if endpoint.startswith("http://") or endpoint.startswith("https://"):
+            return endpoint
+        return f"{self.base_url}/{endpoint.lstrip('/')}"
+    
+    def get(
+        self,
+        endpoint: str,
+        params: Optional[Dict[str, Any]] = None,
+        headers: Optional[Dict[str, str]] = None
+    ) -> Dict[str, Any]:
+        """
+        Perform GET request.
+        
+        Args:
+            endpoint: API endpoint
+            params: Query parameters
+            headers: Additional headers
+            
+        Returns:
+            Response data as dictionary
+            
+        Raises:
+            NetworkError: If request fails
+        """
+        url = self._build_url(endpoint)
+        req_headers = {**self.headers, **(headers or {})}
+        
+        try:
+            response = self.session.get(
+                url,
+                params=params,
+                headers=req_headers,
+                timeout=self.timeout
+            )
+            response.raise_for_status()
+            return response.json()
+        except requests.RequestException as e:
+            raise NetworkError(f"GET request failed: {e}")
+    
+    def post(
+        self,
+        endpoint: str,
+        data: Optional[Dict[str, Any]] = None,
+        json: Optional[Dict[str, Any]] = None,
+        headers: Optional[Dict[str, str]] = None
+    ) -> Dict[str, Any]:
+        """
+        Perform POST request.
+        
+        Args:
+            endpoint: API endpoint
+            data: Form data
+            json: JSON data
+            headers: Additional headers
+            
+        Returns:
+            Response data as dictionary
+            
+        Raises:
+            NetworkError: If request fails
+        """
+        url = self._build_url(endpoint)
+        req_headers = {**self.headers, **(headers or {})}
+        
+        try:
+            response = self.session.post(
+                url,
+                data=data,
+                json=json,
+                headers=req_headers,
+                timeout=self.timeout
+            )
+            response.raise_for_status()
+            return response.json()
+        except requests.RequestException as e:
+            raise NetworkError(f"POST request failed: {e}")
+    
+    def put(
+        self,
+        endpoint: str,
+        data: Optional[Dict[str, Any]] = None,
+        json: Optional[Dict[str, Any]] = None,
+        headers: Optional[Dict[str, str]] = None
+    ) -> Dict[str, Any]:
+        """
+        Perform PUT request.
+        
+        Args:
+            endpoint: API endpoint
+            data: Form data
+            json: JSON data
+            headers: Additional headers
+            
+        Returns:
+            Response data as dictionary
+            
+        Raises:
+            NetworkError: If request fails
+        """
+        url = self._build_url(endpoint)
+        req_headers = {**self.headers, **(headers or {})}
+        
+        try:
+            response = self.session.put(
+                url,
+                data=data,
+                json=json,
+                headers=req_headers,
+                timeout=self.timeout
+            )
+            response.raise_for_status()
+            return response.json()
+        except requests.RequestException as e:
+            raise NetworkError(f"PUT request failed: {e}")
+    
+    def delete(
+        self,
+        endpoint: str,
+        params: Optional[Dict[str, Any]] = None,
+        headers: Optional[Dict[str, str]] = None
+    ) -> Dict[str, Any]:
+        """
+        Perform DELETE request.
+        
+        Args:
+            endpoint: API endpoint
+            params: Query parameters
+            headers: Additional headers
+            
+        Returns:
+            Response data as dictionary
+            
+        Raises:
+            NetworkError: If request fails
+        """
+        url = self._build_url(endpoint)
+        req_headers = {**self.headers, **(headers or {})}
+        
+        try:
+            response = self.session.delete(
+                url,
+                params=params,
+                headers=req_headers,
+                timeout=self.timeout
+            )
+            response.raise_for_status()
+            return response.json() if response.content else {}
+        except requests.RequestException as e:
+            raise NetworkError(f"DELETE request failed: {e}")
+    
+    def close(self) -> None:
+        """Close the HTTP session."""
+        self.session.close()
+    
+    def __enter__(self):
+        """Context manager entry."""
+        return self
+    
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        """Context manager exit."""
+        self.close()
diff --git a/aitbc/json_utils.py b/aitbc/json_utils.py
new file mode 100644
index 00000000..14ea5963
--- /dev/null
+++ b/aitbc/json_utils.py
@@ -0,0 +1,157 @@
+"""
+AITBC JSON Utilities
+Centralized JSON loading, saving, and manipulation
+"""
+
+import json
+from pathlib import Path
+from typing import Dict, Any, List, Optional
+from .exceptions import ConfigurationError
+
+
+def load_json(path: Path) -> Dict[str, Any]:
+    """
+    Load JSON data from a file.
+    
+    Args:
+        path: Path to JSON file
+        
+    Returns:
+        Parsed JSON data as dictionary
+        
+    Raises:
+        ConfigurationError: If file cannot be read or parsed
+    """
+    try:
+        with open(path, 'r') as f:
+            return json.load(f)
+    except FileNotFoundError:
+        raise ConfigurationError(f"JSON file not found: {path}")
+    except json.JSONDecodeError as e:
+        raise ConfigurationError(f"Invalid JSON in {path}: {e}")
+
+
+def save_json(data: Dict[str, Any], path: Path, indent: int = 2) -> None:
+    """
+    Save JSON data to a file.
+    
+    Args:
+        data: Dictionary to save as JSON
+        path: Path to output file
+        indent: JSON indentation level
+    """
+    path.parent.mkdir(parents=True, exist_ok=True)
+    with open(path, 'w') as f:
+        json.dump(data, f, indent=indent)
+
+
+def merge_json(*paths: Path) -> Dict[str, Any]:
+    """
+    Merge multiple JSON files, later files override earlier ones.
+    
+    Args:
+        *paths: Variable number of JSON file paths
+        
+    Returns:
+        Merged dictionary
+    """
+    merged = {}
+    for path in paths:
+        data = load_json(path)
+        merged.update(data)
+    return merged
+
+
+def json_to_string(data: Dict[str, Any], indent: int = 2) -> str:
+    """
+    Convert dictionary to JSON string.
+    
+    Args:
+        data: Dictionary to convert
+        indent: JSON indentation level
+        
+    Returns:
+        JSON string
+    """
+    return json.dumps(data, indent=indent)
+
+
+def string_to_json(json_str: str) -> Dict[str, Any]:
+    """
+    Parse JSON string to dictionary.
+    
+    Args:
+        json_str: JSON string
+        
+    Returns:
+        Parsed dictionary
+        
+    Raises:
+        ConfigurationError: If string cannot be parsed
+    """
+    try:
+        return json.loads(json_str)
+    except json.JSONDecodeError as e:
+        raise ConfigurationError(f"Invalid JSON string: {e}")
+
+
+def get_nested_value(data: Dict[str, Any], *keys: str, default: Any = None) -> Any:
+    """
+    Get a nested value from a dictionary using dot notation or key chain.
+    
+    Args:
+        data: Dictionary to search
+        *keys: Keys to traverse (e.g., "a", "b", "c" for data["a"]["b"]["c"])
+        default: Default value if key not found
+        
+    Returns:
+        Nested value or default
+    """
+    current = data
+    for key in keys:
+        if isinstance(current, dict) and key in current:
+            current = current[key]
+        else:
+            return default
+    return current
+
+
+def set_nested_value(data: Dict[str, Any], *keys: str, value: Any) -> None:
+    """
+    Set a nested value in a dictionary using key chain.
+    
+    Args:
+        data: Dictionary to modify
+        *keys: Keys to traverse (e.g., "a", "b", "c" for data["a"]["b"]["c"])
+        value: Value to set
+    """
+    current = data
+    for key in keys[:-1]:
+        if key not in current:
+            current[key] = {}
+        current = current[key]
+    current[keys[-1]] = value
+
+
+def flatten_json(data: Dict[str, Any], separator: str = ".") -> Dict[str, Any]:
+    """
+    Flatten a nested dictionary using dot notation.
+    
+    Args:
+        data: Nested dictionary
+        separator: Separator for flattened keys
+        
+    Returns:
+        Flattened dictionary
+    """
+    def _flatten(obj: Any, parent_key: str = "") -> Dict[str, Any]:
+        items = {}
+        if isinstance(obj, dict):
+            for key, value in obj.items():
+                new_key = f"{parent_key}{separator}{key}" if parent_key else key
+                items.update(_flatten(value, new_key))
+        else:
+            items[parent_key] = obj
+        return items
+    
+    return _flatten(data)
diff --git a/aitbc/paths.py b/aitbc/paths.py
new file mode 100644
index 00000000..e5996b05
--- /dev/null
+++ b/aitbc/paths.py
@@ -0,0 +1,153 @@
+"""
+AITBC Path Utilities
+Centralized path resolution and directory management
+"""
+
+from pathlib import Path
+from .constants import DATA_DIR, CONFIG_DIR, LOG_DIR, REPO_DIR
+from .exceptions import ConfigurationError
+
+
+def get_data_path(subpath: str = "") -> Path:
+    """
+    Get a path within the AITBC data directory.
+    
+    Args:
+        subpath: Optional subpath relative to data directory
+        
+    Returns:
+        Full path to data directory or subpath
+    """
+    if subpath:
+        return DATA_DIR / subpath
+    return DATA_DIR
+
+
+def get_config_path(filename: str) -> Path:
+    """
+    Get a path within the AITBC configuration directory.
+    
+    Args:
+        filename: Configuration filename
+        
+    Returns:
+        Full path to configuration file
+    """
+    return CONFIG_DIR / filename
+
+
+def get_log_path(filename: str) -> Path:
+    """
+    Get a path within the AITBC log directory.
+    
+    Args:
+        filename: Log filename
+        
+    Returns:
+        Full path to log file
+    """
+    return LOG_DIR / filename
+
+
+def get_repo_path(subpath: str = "") -> Path:
+    """
+    Get a path within the AITBC repository.
+    
+    Args:
+        subpath: Optional subpath relative to repository
+        
+    Returns:
+        Full path to repository or subpath
+    """
+    if subpath:
+        return REPO_DIR / subpath
+    return REPO_DIR
+
+
+def ensure_dir(path: Path) -> Path:
+    """
+    Ensure a directory exists, creating it if necessary.
+    
+    Args:
+        path: Directory path
+        
+    Returns:
+        The path (guaranteed to exist)
+    """
+    path.mkdir(parents=True, exist_ok=True)
+    return path
+
+
+def ensure_file_dir(filepath: Path) -> Path:
+    """
+    Ensure the parent directory of a file exists.
+    
+    Args:
+        filepath: File path
+        
+    Returns:
+        The parent directory path (guaranteed to exist)
+    """
+    return ensure_dir(filepath.parent)
+
+
+def resolve_path(path: str, base: Path = REPO_DIR) -> Path:
+    """
+    Resolve a path relative to a base directory.
+    
+    Args:
+        path: Path to resolve (can be absolute or relative)
+        base: Base directory for relative paths
+        
+    Returns:
+        Resolved absolute path
+    """
+    p = Path(path)
+    if p.is_absolute():
+        return p
+    return base / p
+
+
+def get_keystore_path(wallet_name: str = "") -> Path:
+    """
+    Get a path within the AITBC keystore directory.
+    
+    Args:
+        wallet_name: Optional wallet name for specific keystore file
+        
+    Returns:
+        Full path to keystore directory or specific wallet file
+    """
+    keystore_dir = DATA_DIR / "keystore"
+    if wallet_name:
+        return keystore_dir / f"{wallet_name}.json"
+    return keystore_dir
+
+
+def get_blockchain_data_path(chain_id: str = "ait-mainnet") -> Path:
+    """
+    Get a path within the blockchain data directory.
+    
+    Args:
+        chain_id: Chain identifier
+        
+    Returns:
+        Full path to blockchain data directory
+    """
+    return DATA_DIR / "data" / chain_id
+
+
+def get_marketplace_data_path(subpath: str = "") -> Path:
+    """
+    Get a path within the marketplace data directory.
+    
+    Args:
+        subpath: Optional subpath relative to marketplace directory
+        
+    Returns:
+        Full path to marketplace data directory or subpath
+    """
+    marketplace_dir = DATA_DIR / "marketplace"
+    if subpath:
+        return marketplace_dir / subpath
+    return marketplace_dir
diff --git a/apps/blockchain-node/src/aitbc_chain/sync.py b/apps/blockchain-node/src/aitbc_chain/sync.py
index ae3fbe60..8764fb1d 100755
--- a/apps/blockchain-node/src/aitbc_chain/sync.py
+++ b/apps/blockchain-node/src/aitbc_chain/sync.py
@@ -355,6 +355,13 @@ class ChainSync:
                     logger.warning(f"[SYNC] Failed to apply transaction {tx_hash}: {error_msg}")
                     # For now, log warning but continue (to be enforced in production)
 
+                # Extract type from transaction data
+                tx_type = tx_data.get("type", "TRANSFER")
+                if tx_type:
+                    tx_type = tx_type.upper()
+                else:
+                    tx_type = "TRANSFER"
+                
                 tx = ChainTransaction(
                     chain_id=self._chain_id,
                     tx_hash=tx_hash,
@@ -362,6 +369,7 @@ class ChainSync:
                     sender=sender_addr,
                     recipient=recipient_addr,
                     payload=tx_data,
+                    type=tx_type,
                 )
                 session.add(tx)