diff --git a/docs/api.rst b/docs/api.rst
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -83,6 +83,8 @@
         default to 0 (not restricted)
     :query string return_types: only return the nodes matching this type;
         default to ``"*"``
+    :query integer max_matching_nodes: how many results to return before stopping;
+        default to 0 (not restricted)
 
     :statuscode 200: success
     :statuscode 400: invalid query string provided
@@ -207,6 +209,8 @@
         default to 0 (not restricted)
     :query string return_types: only return the nodes matching this type;
         default to ``"*"``
+    :query integer max_matching_nodes: how many nodes to return/visit before stopping;
+        default to 0 (not restricted)
 
     :statuscode 200: success
     :statuscode 400: invalid query string provided
diff --git a/swh/graph/cli.py b/swh/graph/cli.py
--- a/swh/graph/cli.py
+++ b/swh/graph/cli.py
@@ -1,9 +1,11 @@
-# Copyright (C) 2019-2020  The Software Heritage developers
+# Copyright (C) 2019-2022  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
+import logging
 from pathlib import Path
+import shlex
 from typing import TYPE_CHECKING, Any, Dict, Set, Tuple
 
 # WARNING: do not import unnecessary things here to keep cli startup time under
@@ -16,6 +18,8 @@
 if TYPE_CHECKING:
     from swh.graph.webgraph import CompressionStep  # noqa
 
+logger = logging.getLogger(__name__)
+
 
 class StepOption(click.ParamType):
     """click type for specifying a compression step on the CLI
@@ -171,13 +175,17 @@
     config = ctx.obj["config"]
     config.setdefault("graph", {})
     config["graph"]["path"] = graph
+
+    logger.debug("Building gPRC server command line")
     cmd, port = build_grpc_server_cmdline(**config["graph"])
 
     java_bin = cmd[0]
     if java_home is not None:
         java_bin = str(Path(java_home) / "bin" / java_bin)
 
-    print(f"Starting the GRPC server on 0.0.0.0:{port}")
+    # XXX: shlex.join() is in 3.8
+    # logger.info("Starting gRPC server: %s", shlex.join(cmd))
+    logger.info("Starting gRPC server: %s", " ".join(shlex.quote(x) for x in cmd))
     os.execvp(java_bin, cmd)
 
 
diff --git a/swh/graph/config.py b/swh/graph/config.py
--- a/swh/graph/config.py
+++ b/swh/graph/config.py
@@ -1,4 +1,4 @@
-# Copyright (C) 2019  The Software Heritage developers
+# Copyright (C) 2019-2022  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
@@ -9,6 +9,8 @@
 
 import psutil
 
+logger = logging.getLogger(__name__)
+
 
 def find_graph_jar():
     """find swh-graph.jar, containing the Java part of swh-graph
@@ -17,6 +19,7 @@
     deployments who fecthed the JAR from pypi)
 
     """
+    logger.debug("Looking for swh-graph JAR")
     swh_graph_root = Path(__file__).parents[2]
     try_paths = [
         swh_graph_root / "java/target/",
@@ -24,13 +27,14 @@
         Path(sys.prefix) / "local/share/swh-graph/",
     ]
     for path in try_paths:
+        logger.debug("Looking for swh-graph JAR in %s", path)
         glob = list(path.glob("swh-graph-*.jar"))
         if glob:
             if len(glob) > 1:
-                logging.warning(
+                logger.warning(
                     "found multiple swh-graph JARs, " "arbitrarily picking one"
                 )
-            logging.info("using swh-graph JAR: {0}".format(glob[0]))
+            logger.info("using swh-graph JAR: {0}".format(glob[0]))
             return str(glob[0])
     raise RuntimeError("swh-graph JAR not found. Have you run `make java`?")
 
@@ -42,10 +46,13 @@
         # Use 0.1% of the RAM as a batch size:
         # ~1 billion for big servers, ~10 million for small desktop machines
         conf["batch_size"] = min(int(psutil.virtual_memory().total / 1000), 2**30 - 1)
+        logger.debug("batch_size not configured, defaulting to %s", conf["batch_size"])
     if "llp_gammas" not in conf:
         conf["llp_gammas"] = "-0,-1,-2,-3,-4"
+        logger.debug("llp_gammas not configured, defaulting to %s", conf["llp_gammas"])
     if "max_ram" not in conf:
         conf["max_ram"] = str(int(psutil.virtual_memory().total * 0.9))
+        logger.debug("max_ram not configured, defaulting to %s", conf["max_ram"])
     if "java_tool_options" not in conf:
         conf["java_tool_options"] = " ".join(
             [
@@ -59,6 +66,10 @@
                 "-XX:+ResizeTLAB",
             ]
         )
+        logger.debug(
+            "java_tool_options not providing, defaulting to %s",
+            conf["java_tool_options"],
+        )
     conf["java_tool_options"] = conf["java_tool_options"].format(
         max_ram=conf["max_ram"]
     )
diff --git a/swh/graph/grpc_server.py b/swh/graph/grpc_server.py
--- a/swh/graph/grpc_server.py
+++ b/swh/graph/grpc_server.py
@@ -16,12 +16,17 @@
 
 from swh.graph.config import check_config
 
+logger = logging.getLogger(__name__)
+
 
 def build_grpc_server_cmdline(**config):
     port = config.pop("port", None)
     if port is None:
         port = aiohttp.test_utils.unused_port()
+        logger.debug("Port not configured, using random port %s", port)
+    logger.debug("Checking configuration and populating default values")
     config = check_config(config)
+    logger.debug("Configuration: %r", config)
     cmd = [
         "java",
         "--class-path",
@@ -39,8 +44,8 @@
     cmd, port = build_grpc_server_cmdline(**config)
     print(cmd)
     # XXX: shlex.join() is in 3.8
-    # logging.info("Starting RPC server: %s", shlex.join(cmd))
-    logging.info("Starting GRPC server: %s", " ".join(shlex.quote(x) for x in cmd))
+    # logger.info("Starting gRPC server: %s", shlex.join(cmd))
+    logger.info("Starting gRPC server: %s", " ".join(shlex.quote(x) for x in cmd))
     server = subprocess.Popen(cmd)
     return server, port
 
@@ -50,5 +55,5 @@
     try:
         server.wait(timeout=timeout)
     except subprocess.TimeoutExpired:
-        logging.warning("Server did not terminate, sending kill signal...")
+        logger.warning("Server did not terminate, sending kill signal...")
         server.kill()
diff --git a/swh/graph/http_client.py b/swh/graph/http_client.py
--- a/swh/graph/http_client.py
+++ b/swh/graph/http_client.py
@@ -85,7 +85,13 @@
         )
 
     def visit_nodes(
-        self, src, edges="*", direction="forward", max_edges=0, return_types="*"
+        self,
+        src,
+        edges="*",
+        direction="forward",
+        max_edges=0,
+        return_types="*",
+        max_matching_nodes=0,
     ):
         return self.get_lines(
             "visit/nodes/{}".format(src),
@@ -94,6 +100,7 @@
                 "direction": direction,
                 "max_edges": max_edges,
                 "return_types": return_types,
+                "max_matching_nodes": max_matching_nodes,
             },
         )
 
@@ -160,8 +167,14 @@
             params={"edges": edges, "direction": direction},
         )
 
-    def count_visit_nodes(self, src, edges="*", direction="forward"):
+    def count_visit_nodes(
+        self, src, edges="*", direction="forward", max_matching_nodes=0
+    ):
         return self.get(
             "visit/nodes/count/{}".format(src),
-            params={"edges": edges, "direction": direction},
+            params={
+                "edges": edges,
+                "direction": direction,
+                "max_matching_nodes": max_matching_nodes,
+            },
         )
diff --git a/swh/graph/http_naive_client.py b/swh/graph/http_naive_client.py
--- a/swh/graph/http_naive_client.py
+++ b/swh/graph/http_naive_client.py
@@ -190,11 +190,15 @@
         direction: str = "forward",
         max_edges: int = 0,
         return_types: str = "*",
+        max_matching_nodes: int = 0,
     ) -> Iterator[str]:
         # TODO: max_edges
-        yield from filter_node_types(
+        res = filter_node_types(
             return_types, self.graph.get_subgraph(src, edges, direction)
         )
+        if max_matching_nodes > 0:
+            res = itertools.islice(res, max_matching_nodes)
+        return res
 
     @check_arguments
     def visit_edges(
@@ -279,9 +283,16 @@
 
     @check_arguments
     def count_visit_nodes(
-        self, src: str, edges: str = "*", direction: str = "forward"
+        self,
+        src: str,
+        edges: str = "*",
+        direction: str = "forward",
+        max_matching_nodes: int = 0,
     ) -> int:
-        return len(self.graph.get_subgraph(src, edges, direction))
+        res = len(self.graph.get_subgraph(src, edges, direction))
+        if max_matching_nodes > 0:
+            res = min(max_matching_nodes, res)
+        return res
 
 
 class Graph:
diff --git a/swh/graph/tests/test_http_client.py b/swh/graph/tests/test_http_client.py
--- a/swh/graph/tests/test_http_client.py
+++ b/swh/graph/tests/test_http_client.py
@@ -91,6 +91,27 @@
     assert set(actual) == set(expected)
 
 
+@pytest.mark.parametrize("max_matching_nodes", [0, 1, 2, 3, 4, 5, 10, 1 << 31])
+def test_visit_nodes_limit(graph_client, max_matching_nodes):
+    actual = list(
+        graph_client.visit_nodes(
+            "swh:1:rel:0000000000000000000000000000000000000010",
+            edges="rel:rev,rev:rev",
+            max_matching_nodes=max_matching_nodes,
+        )
+    )
+    expected = [
+        "swh:1:rel:0000000000000000000000000000000000000010",
+        "swh:1:rev:0000000000000000000000000000000000000009",
+        "swh:1:rev:0000000000000000000000000000000000000003",
+    ]
+    if max_matching_nodes == 0:
+        assert set(actual) == set(expected)
+    else:
+        assert set(actual) <= set(expected)
+        assert len(actual) == min(3, max_matching_nodes)
+
+
 def test_visit_nodes_filtered(graph_client):
     actual = list(
         graph_client.visit_nodes(