diff --git a/.gitignore b/.gitignore
index db7e7fcf9..b1caaf8a8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -36,7 +36,7 @@ model_output/
 /*.Rcheck/
 
 # RStudio files
-.Rproj.user/
+.Rproj.user
 flepiMoP.Rproj
 *.Rproj
 
@@ -64,7 +64,8 @@ packrat/lib*/
 dist/
 SEIR.egg-info/
 Outcomes.egg-info/
-.Rproj.user
+venv/
+.venv/
 
 # R package manuals
 man/
@@ -74,3 +75,6 @@ flepimop/gempyor_pkg/get_value.prof
 flepimop/gempyor_pkg/tests/seir/.coverage
 flepimop/gempyor_pkg/tests/seir/.coverage.kojis-mbp-8.sph.ad.jhsph.edu.90615.974746
 flepimop/gempyor_pkg/.coverage
+
+# Environment variables
+.env
diff --git a/flepimop/gempyor_pkg/setup.cfg b/flepimop/gempyor_pkg/setup.cfg
index f63f130da..e5fb0902a 100644
--- a/flepimop/gempyor_pkg/setup.cfg
+++ b/flepimop/gempyor_pkg/setup.cfg
@@ -42,7 +42,9 @@ install_requires =
 test =
     pytest
     mock
-
+aws =
+    boto3
+    botocore
 
 [options.entry_points]
 console_scripts =
diff --git a/flepimop/gempyor_pkg/src/gempyor/utils.py b/flepimop/gempyor_pkg/src/gempyor/utils.py
index 85820d5b2..990acdf30 100644
--- a/flepimop/gempyor_pkg/src/gempyor/utils.py
+++ b/flepimop/gempyor_pkg/src/gempyor/utils.py
@@ -9,8 +9,6 @@
 import time
 from typing import List, Dict, Literal
 
-import boto3
-from botocore.exceptions import ClientError
 import confuse
 import numpy as np
 import numpy.typing as npt
@@ -347,7 +345,7 @@ def as_random_distribution(self):
 
 
 def list_filenames(
-    folder: str | bytes | os.PathLike = ".", 
+    folder: str | bytes | os.PathLike = ".",
     filters: str | list[str] = [],
 ) -> list[str]:
     """Return the list of all filenames and paths in the provided folder.
@@ -636,12 +634,19 @@ def download_file_from_s3(name_map: Dict[str, str]) -> None:
         >>> download_file_from_s3(name_map)
         # This will raise a ValueError indicating the invalid S3 URI format.
     """
+    try:
+        import boto3
+        from botocore.exceptions import ClientError
+    except ModuleNotFoundError:
+        raise ModuleNotFoundError((
+            "No module named 'boto3', which is required for "
+            "gempyor.utils.download_file_from_s3. Please install the aws target."
+        ))
     s3 = boto3.client("s3")
     first_output_filename = next(iter(name_map.values()))
     output_dir = os.path.dirname(first_output_filename)
     if not os.path.exists(output_dir):
         os.makedirs(output_dir)
-
     for s3_uri in name_map:
         try:
             if s3_uri.startswith("s3://"):