feat(sendgrid): support an optional SENDGRID_REPLY_TO_EMAIL on outbound emails

enterprise/litellm_enterprise/enterprise_callbacks/send_emails/sendgrid_email.py

@@ -5,7 +5,7 @@ Docs: https://docs.sendgrid.com/api-reference/mail-send/mail-send
 """
 
 import os
-from typing import List
+from typing import Final, List
 
 from litellm._logging import verbose_logger
 from litellm.llms.custom_httpx.http_handler import (
@@ -25,6 +25,12 @@ class SendGridEmailLogger(BaseEmailLogger):
 
     Required env vars:
     - SENDGRID_API_KEY
+
+    Optional env vars:
+    - SENDGRID_SENDER_EMAIL: Override the sender address. When unset, falls back to
+      the `from_email` argument passed by the caller.
+    - SENDGRID_REPLY_TO_EMAIL: Address recipients reply to. When unset, SendGrid
+      defaults Reply-To to the sender address.
     """
 
     def __init__(self, internal_usage_cache=None, **kwargs):
@@ -34,6 +40,7 @@ class SendGridEmailLogger(BaseEmailLogger):
         )
         self.sendgrid_api_key = os.getenv("SENDGRID_API_KEY")
         self.sendgrid_sender_email = os.getenv("SENDGRID_SENDER_EMAIL")
+        self.sendgrid_reply_to_email = os.getenv("SENDGRID_REPLY_TO_EMAIL")
         verbose_logger.debug("SendGrid Email Logger initialized.")
 
     async def send_email(
@@ -54,8 +61,15 @@ class SendGridEmailLogger(BaseEmailLogger):
             f"Sending email via SendGrid from {sender_email} to {to_email} with subject {subject}"
         )
 
+        reply_to: Final = (
+            {"reply_to": {"email": self.sendgrid_reply_to_email}}
+            if self.sendgrid_reply_to_email
+            else {}
+        )
+
         payload = {
             "from": {"email": sender_email},
+            **reply_to,
             "personalizations": [
                 {
                     "to": [{"email": email} for email in to_email],

tests/test_litellm/enterprise/enterprise_callbacks/send_emails/test_sendgrid_email.py

@@ -133,3 +133,46 @@ async def test_send_email_multiple_recipients(mock_env_vars, mock_async_client):
         {"email": "recipient1@example.com"},
         {"email": "recipient2@example.com"},
     ]
+
+
+@pytest.mark.asyncio
+async def test_send_email_sets_reply_to_when_configured(monkeypatch, mock_async_client):
+    """SENDGRID_REPLY_TO_EMAIL is sent as the payload's reply_to and leaves from alone."""
+    monkeypatch.setenv("SENDGRID_API_KEY", "test_api_key")
+    monkeypatch.delenv("SENDGRID_SENDER_EMAIL", raising=False)
+    monkeypatch.setenv("SENDGRID_REPLY_TO_EMAIL", "litellm-alerts@example.com")
+
+    logger = SendGridEmailLogger()
+    logger.async_httpx_client = mock_async_client
+
+    await logger.send_email(
+        from_email="no-reply@example.com",
+        to_email=["recipient@example.com"],
+        subject="Test Subject",
+        html_body="<p>Test email body</p>",
+    )
+
+    payload = mock_async_client.post.call_args[1]["json"]
+    assert payload["reply_to"] == {"email": "litellm-alerts@example.com"}
+    assert payload["from"] == {"email": "no-reply@example.com"}
+
+
+@pytest.mark.asyncio
+async def test_send_email_omits_reply_to_when_not_configured(monkeypatch, mock_async_client):
+    """With SENDGRID_REPLY_TO_EMAIL unset the key is absent, not null, so SendGrid
+    keeps defaulting Reply-To to the sender."""
+    monkeypatch.setenv("SENDGRID_API_KEY", "test_api_key")
+    monkeypatch.delenv("SENDGRID_REPLY_TO_EMAIL", raising=False)
+
+    logger = SendGridEmailLogger()
+    logger.async_httpx_client = mock_async_client
+
+    await logger.send_email(
+        from_email="no-reply@example.com",
+        to_email=["recipient@example.com"],
+        subject="Test Subject",
+        html_body="<p>Test email body</p>",
+    )
+
+    payload = mock_async_client.post.call_args[1]["json"]
+    assert "reply_to" not in payload