diff --git a/pueblo/io/universal.py b/pueblo/io/universal.py
index c9d3f6d..922003a 100644
--- a/pueblo/io/universal.py
+++ b/pueblo/io/universal.py
@@ -41,9 +41,16 @@ def open_url(url: str) -> PathPlus:
     -----------
     fs = Path("github://path/to/document.md", username="foobar", token="ghp_lalala", org="acme", repo="sweet-camino")
     """
-    uri = URL(url)
+    uri = None
+    try:
+        uri = URL(url)
+    except ValueError as ex:
+        if "host is required for absolute urls" in str(ex):
+            pass
+        else:
+            raise
 
-    if uri.scheme.startswith("github+https"):
+    if uri and uri.scheme.startswith("github+https"):
         path_fragments = uri.path.split("/")[1:]
         path_kwargs = {
             "username": uri.user,
@@ -60,7 +67,10 @@ def open_url(url: str) -> PathPlus:
         path = PathPlus(downstream_url, **path_kwargs)
 
     else:
-        path = PathPlus(url)
+        kwargs = {}
+        if url.startswith("s3://"):
+            kwargs["anon"] = True
+        path = PathPlus(url, **kwargs)
     return path
 
 
diff --git a/pyproject.toml b/pyproject.toml
index f17cd4a..c75d6c9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -92,8 +92,9 @@ develop = [
   "validate-pyproject<0.16",
 ]
 fileio = [
-  "fsspec[adlfs,dask,gcs,git,github,http,s3,smb]<2023.11",
+  "fsspec[abfs,dask,gcs,git,github,http,s3,smb]<2023.11",
   "pathlibfs<0.6",
+  "python-magic<0.5",
   "yarl<1.10",
 ]
 nlp = [
diff --git a/tests/test_io.py b/tests/test_io.py
index 258d92f..7d5747e 100644
--- a/tests/test_io.py
+++ b/tests/test_io.py
@@ -1,4 +1,8 @@
 # ruff: noqa: E402
+import dataclasses
+import typing as t
+
+import magic
 import pytest
 
 pytest.importorskip("pathlibfs")
@@ -60,3 +64,42 @@ def test_path_without_scheme_absolute():
 
 def test_path_without_scheme_relative():
     assert path_without_scheme("/bar/baz") == PathPlus("file:///bar/baz")
+
+
+@dataclasses.dataclass
+class RemoteFile:
+    url: str
+    mimetypes: t.List[str]
+
+
+def remote_files() -> t.List[RemoteFile]:
+    return [
+        RemoteFile(
+            url="https://github.com/daq-tools/skeem/raw/main/tests/testdata/basic.ods",
+            mimetypes=["application/vnd.oasis.opendocument.spreadsheet"],
+        ),
+        RemoteFile(
+            url="github://daq-tools:skeem@/tests/testdata/basic.ods",
+            mimetypes=["application/vnd.oasis.opendocument.spreadsheet"],
+        ),
+        RemoteFile(
+            url="github+https://github.com/daq-tools/skeem/raw/main/tests/testdata/basic.ods",
+            mimetypes=["application/vnd.oasis.opendocument.spreadsheet"],
+        ),
+        RemoteFile(
+            url="gs://gcp-public-data-landsat/LC08/01/001/003/LC08_L1GT_001003_20140812_20170420_01_T2/LC08_L1GT_001003_20140812_20170420_01_T2_B3.TIF",
+            mimetypes=["image/tiff"],
+        ),
+        RemoteFile(
+            url="s3://fmi-gridded-obs-daily-1km/Netcdf/Tday/tday_2023.nc",
+            mimetypes=["application/x-netcdf", "application/octet-stream"],
+        ),
+    ]
+
+
+@pytest.mark.parametrize("remote_file", remote_files(), ids=[rf.url for rf in remote_files()])
+def test_to_io_remote_files(remote_file):
+    with to_io(remote_file.url, mode="rb") as fp:
+        content = fp.read(100)
+        mimetype = magic.from_buffer(content, mime=True)
+        assert mimetype in remote_file.mimetypes