diff --git a/yente/provider/opensearch.py b/yente/provider/opensearch.py
index e97e1898..8973e498 100644
--- a/yente/provider/opensearch.py
+++ b/yente/provider/opensearch.py
@@ -3,7 +3,7 @@
 import logging
 from typing import Any, Dict, List, Optional, cast
 from typing import AsyncIterator
-from opensearchpy import AsyncOpenSearch
+from opensearchpy import AsyncOpenSearch, AWSV4SignerAuth
 from opensearchpy.helpers import async_bulk, BulkIndexError
 from opensearchpy.exceptions import NotFoundError, TransportError
 
@@ -34,13 +34,25 @@ async def create(cls) -> "OpenSearchProvider":
             kwargs["sniff_on_connection_fail"] = True
         if settings.INDEX_USERNAME and settings.INDEX_PASSWORD:
             auth = (settings.INDEX_USERNAME, settings.INDEX_PASSWORD)
-            kwargs["basic_auth"] = auth
+            kwargs["http_auth"] = auth
+        if settings.OPENSEARCH_REGION and settings.OPENSEARCH_SERVICE:
+            from boto3 import Session
+
+            service = settings.OPENSEARCH_SERVICE.lower().strip()
+            if service not in ["es", "aoss"]:
+                raise RuntimeError(f"Invalid OpenSearch service: {service}")
+            credentials = Session().get_credentials()
+            kwargs["http_auth"] = AWSV4SignerAuth(
+                credentials,
+                settings.OPENSEARCH_REGION,
+                settings.OPENSEARCH_SERVICE,
+            )
         if settings.INDEX_CA_CERT:
             kwargs["ca_certs"] = settings.INDEX_CA_CERT
         for retry in range(2, 9):
             try:
                 es = AsyncOpenSearch(**kwargs)
-                await es.cluster.health(wait_for_status="yellow")
+                await es.cluster.health(wait_for_status="yellow", timeout=5)
                 return OpenSearchProvider(es)
             except (TransportError, ConnectionError) as exc:
                 log.error("Cannot connect to OpenSearch: %r" % exc)
diff --git a/yente/settings.py b/yente/settings.py
index bf5a0a65..284970a0 100644
--- a/yente/settings.py
+++ b/yente/settings.py
@@ -170,9 +170,6 @@ def random_cron() -> str:
 _INDEX_URL = "http://localhost:9200"
 INDEX_URL = env_legacy("YENTE_INDEX_URL", "YENTE_ELASTICSEARCH_URL", _INDEX_URL)
 
-ES_CLOUD_ID = env_get("YENTE_ELASTICSEARCH_CLOUD_ID")
-# TODO: https://docs.aws.amazon.com/opensearch-service/latest/developerguide/serverless-sdk.html
-
 _INDEX_USERNAME = env_legacy("YENTE_INDEX_USERNAME", "YENTE_ELASTICSEARCH_USERNAME", "")
 INDEX_USERNAME = None if _INDEX_USERNAME == "" else _INDEX_USERNAME
 _INDEX_PASSWORD = env_legacy("YENTE_INDEX_PASSWORD", "YENTE_ELASTICSEARCH_PASSWORD", "")
@@ -187,6 +184,13 @@ def random_cron() -> str:
 INDEX_VERSION = env_str("YENTE_INDEX_VERSION", "009")
 assert len(INDEX_VERSION) == 3, "Index version must be 3 characters long."
 
+# ElasticSearch-only options:
+ES_CLOUD_ID = env_get("YENTE_ELASTICSEARCH_CLOUD_ID")
+
+# OpenSearch-only options:
+OPENSEARCH_REGION = env_get("YENTE_OPENSEARCH_REGION")
+OPENSEARCH_SERVICE = env_get("YENTE_OPENSEARCH_SERVICE")
+
 # Log output can be formatted as JSON:
 LOG_JSON = as_bool(env_str("YENTE_LOG_JSON", "false"))
 LOG_LEVEL = logging.DEBUG if DEBUG else logging.INFO