diff --git a/lightrag/llm/ollama.py b/lightrag/llm/ollama.py
index b013496e..670351bc 100644
--- a/lightrag/llm/ollama.py
+++ b/lightrag/llm/ollama.py
@@ -1,4 +1,6 @@
 from collections.abc import AsyncIterator
+import os
+import re
 
 import pipmaster as pm
 
@@ -22,10 +24,30 @@ from lightrag.exceptions import (
 from lightrag.api import __api_version__
 
 import numpy as np
-from typing import Union
+from typing import Optional, Union
 from lightrag.utils import logger
 
 
+_OLLAMA_CLOUD_HOST = "https://ollama.com"
+_CLOUD_MODEL_SUFFIX_PATTERN = re.compile(r"(?:-cloud|:cloud)$")
+
+
+def _coerce_host_for_cloud_model(host: Optional[str], model: object) -> Optional[str]:
+    if host:
+        return host
+    try:
+        model_name_str = str(model) if model is not None else ""
+    except (TypeError, ValueError, AttributeError) as e:
+        logger.warning(f"Failed to convert model to string: {e}, using empty string")
+        model_name_str = ""
+    if _CLOUD_MODEL_SUFFIX_PATTERN.search(model_name_str):
+        logger.debug(
+            f"Detected cloud model '{model_name_str}', using Ollama Cloud host"
+        )
+        return _OLLAMA_CLOUD_HOST
+    return host
+
+
 @retry(
     stop=stop_after_attempt(3),
     wait=wait_exponential(multiplier=1, min=4, max=10),
@@ -53,6 +75,9 @@ async def _ollama_model_if_cache(
         timeout = None
     kwargs.pop("hashing_kv", None)
     api_key = kwargs.pop("api_key", None)
+    # fallback to environment variable when not provided explicitly
+    if not api_key:
+        api_key = os.getenv("OLLAMA_API_KEY")
     headers = {
         "Content-Type": "application/json",
         "User-Agent": f"LightRAG/{__api_version__}",
@@ -60,6 +85,8 @@ async def _ollama_model_if_cache(
     if api_key:
         headers["Authorization"] = f"Bearer {api_key}"
 
+    host = _coerce_host_for_cloud_model(host, model)
+
     ollama_client = ollama.AsyncClient(host=host, timeout=timeout, headers=headers)
 
     try:
@@ -144,6 +171,8 @@ async def ollama_model_complete(
 
 async def ollama_embed(texts: list[str], embed_model, **kwargs) -> np.ndarray:
     api_key = kwargs.pop("api_key", None)
+    if not api_key:
+        api_key = os.getenv("OLLAMA_API_KEY")
     headers = {
         "Content-Type": "application/json",
         "User-Agent": f"LightRAG/{__api_version__}",
@@ -154,6 +183,8 @@ async def ollama_embed(texts: list[str], embed_model, **kwargs) -> np.ndarray:
     host = kwargs.pop("host", None)
     timeout = kwargs.pop("timeout", None)
 
+    host = _coerce_host_for_cloud_model(host, embed_model)
+
     ollama_client = ollama.AsyncClient(host=host, timeout=timeout, headers=headers)
     try:
         options = kwargs.pop("options", {})