diff --git a/prepare.py b/prepare.py
index 06bea9165..f915672b5 100644
--- a/prepare.py
+++ b/prepare.py
@@ -38,7 +38,8 @@
 CACHE_DIR = os.path.join(os.path.expanduser("~"), ".cache", "autoresearch")
 DATA_DIR = os.path.join(CACHE_DIR, "data")
 TOKENIZER_DIR = os.path.join(CACHE_DIR, "tokenizer")
-BASE_URL = "https://huggingface.co/datasets/karpathy/climbmix-400b-shuffle/resolve/main"
+_HF_ENDPOINT = os.environ.get("HF_ENDPOINT", "https://huggingface.co")
+BASE_URL = f"{_HF_ENDPOINT}/datasets/karpathy/climbmix-400b-shuffle/resolve/main"
 MAX_SHARD = 6542 # the last datashard is shard_06542.parquet
 VAL_SHARD = MAX_SHARD  # pinned validation shard (shard_06542)
 VAL_FILENAME = f"shard_{VAL_SHARD:05d}.parquet"