diff --git a/swh/core/config.py b/swh/core/config.py
--- a/swh/core/config.py
+++ b/swh/core/config.py
@@ -9,6 +9,7 @@
 import os
 from typing import Any, Callable, Dict, List, Optional, Tuple
 
+from deprecated import deprecated
 import yaml
 
 logger = logging.getLogger(__name__)
@@ -286,6 +287,29 @@
     return conf
 
 
+def load_from_envvar(default_config: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
+    """Load configuration yaml file from the environment variable SWH_CONFIG_FILENAME,
+    eventually enriched with default configuration key/value from the default_config
+    dict if provided.
+
+    Returns:
+        Configuration dict
+
+    Raises:
+        AssertionError if SWH_CONFIG_FILENAME is undefined
+
+    """
+    assert (
+        "SWH_CONFIG_FILENAME" in os.environ
+    ), "SWH_CONFIG_FILENAME environment variable is undefined."
+
+    cfg_path = os.environ["SWH_CONFIG_FILENAME"]
+    cfg = read_raw_config(config_basepath(cfg_path))
+    cfg = merge_configs(default_config or {}, cfg)
+    return cfg
+
+
+@deprecated(version="0.3.2", reason="Use swh.core.config.load_from_envvar instead")
 class SWHConfig:
     """Mixin to add configuration parsing abilities to classes
 
diff --git a/swh/core/tests/test_config.py b/swh/core/tests/test_config.py
--- a/swh/core/tests/test_config.py
+++ b/swh/core/tests/test_config.py
@@ -326,3 +326,39 @@
             config.merge_configs({"a": v}, {"a": {}})
         with pytest.raises(TypeError):
             config.merge_configs({"a": {}}, {"a": v})
+
+
+def test_load_from_envvar_no_environment_var_swh_config_filename_set():
+    """Without SWH_CONFIG_FILENAME set, load_from_envvar raises"""
+
+    with pytest.raises(AssertionError, match="SWH_CONFIG_FILENAME environment"):
+        config.load_from_envvar()
+
+
+def test_load_from_envvar_no_default_config(swh_config, monkeypatch):
+    config_path = str(swh_config)
+    monkeypatch.setenv("SWH_CONFIG_FILENAME", config_path)
+
+    actual_config = config.load_from_envvar()
+
+    expected_config = config.read(config_path)
+    assert actual_config == expected_config
+
+
+def test_load_from_envvar_with_default_config(swh_config, monkeypatch):
+    default_config = {
+        "number": 666,
+        "something-cool": ["something", "cool"],
+    }
+
+    config_path = str(swh_config)
+    monkeypatch.setenv("SWH_CONFIG_FILENAME", config_path)
+
+    actual_config = config.load_from_envvar(default_config)
+
+    expected_config = config.read(config_path)
+    expected_config.update(
+        {"number": 666, "something-cool": ["something", "cool"],}
+    )
+
+    assert actual_config == expected_config