diff --git a/scaleway/scaleway/instance/v1/tests/cassettes/server.cassette.yaml b/scaleway/scaleway/instance/v1/tests/cassettes/server.cassette.yaml
new file mode 100644
index 000000000..20eeefb7b
--- /dev/null
+++ b/scaleway/scaleway/instance/v1/tests/cassettes/server.cassette.yaml
@@ -0,0 +1,124 @@
+interactions:
+- request:
+    body: '{"project": "11111111-1111-1111-1111-111111111111", "commercial_type":
+      "DEV1-S", "name": "test-sdk-python-fixture", "dynamic_ip_required": false, "image":
+      "c00ae53c-1e29-4087-a384-47f3c5c1cd84", "protected": false, "boot_type": "local"}'
+    headers:
+      Content-Length:
+      - '236'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: POST
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers
+  response:
+    body:
+      string: '{"server": {"id": "66a3b25b-4518-43c3-9e61-33b82873d617", "name": "test-sdk-python-fixture",
+        "arch": "x86_64", "commercial_type": "DEV1-S", "boot_type": "local", "organization":
+        "11111111-1111-1111-1111-111111111111", "project": "11111111-1111-1111-1111-111111111111",
+        "hostname": "test-sdk-python-fixture", "image": {"id": "c00ae53c-1e29-4087-a384-47f3c5c1cd84",
+        "name": "Ubuntu 20.04 Focal Fossa", "organization": "11111111-1111-1111-1111-111111111111",
+        "project": "11111111-1111-1111-1111-111111111111", "root_volume": {"id": "6644dfd6-0731-45cc-a581-62f561eff7bf",
+        "name": "Ubuntu 20.04 Focal Fossa", "volume_type": "l_ssd", "size": 10000000000},
+        "extra_volumes": {}, "public": true, "arch": "x86_64", "creation_date": "2025-02-03T13:36:50.774356+00:00",
+        "modification_date": "2025-02-03T13:36:50.774356+00:00", "default_bootscript":
+        null, "from_server": "", "state": "available", "tags": [], "zone": "fr-par-1"},
+        "volumes": {"0": {"boot": false, "id": "bda6aff6-7ca2-41de-a3fb-47be986c5c0a",
+        "name": "Ubuntu 20.04 Focal Fossa", "volume_type": "l_ssd", "export_uri":
+        null, "organization": "11111111-1111-1111-1111-111111111111", "project": "11111111-1111-1111-1111-111111111111",
+        "server": {"id": "66a3b25b-4518-43c3-9e61-33b82873d617", "name": "test-sdk-python-fixture"},
+        "size": 20000000000, "state": "available", "creation_date": "2025-09-16T17:38:27.303680+00:00",
+        "modification_date": "2025-09-16T17:38:27.303680+00:00", "tags": [], "zone":
+        "fr-par-1"}}, "tags": [], "state": "stopped", "protected": false, "state_detail":
+        "", "public_ip": null, "public_ips": [], "mac_address": "de:00:00:c8:be:d7",
+        "routed_ip_enabled": true, "ipv6": null, "extra_networks": [], "dynamic_ip_required":
+        false, "enable_ipv6": false, "private_ip": null, "creation_date": "2025-09-16T17:38:27.303680+00:00",
+        "modification_date": "2025-09-16T17:38:27.303680+00:00", "bootscript": null,
+        "security_group": {"id": "1c1fc99f-b2de-408d-9eb0-da801a3e2744", "name": "Default
+        security group"}, "location": null, "maintenances": [], "allowed_actions":
+        ["poweron", "backup"], "placement_group": null, "private_nics": [], "zone":
+        "fr-par-1", "filesystems": [], "end_of_service": false}}'
+    headers:
+      content-length:
+      - '2163'
+      date:
+      - Tue, 16 Sep 2025 17:38:27 GMT
+      location:
+      - https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - cf1425a5-4c54-464b-bfa3-b175537ec160
+    status:
+      code: 201
+      message: Created
+- request:
+    body: '{}'
+    headers:
+      Content-Length:
+      - '2'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617
+  response:
+    body:
+      string: '{"server": {"id": "66a3b25b-4518-43c3-9e61-33b82873d617", "name": "test-sdk-python-fixture",
+        "arch": "x86_64", "commercial_type": "DEV1-S", "boot_type": "local", "organization":
+        "11111111-1111-1111-1111-111111111111", "project": "11111111-1111-1111-1111-111111111111",
+        "hostname": "test-sdk-python-fixture", "image": {"id": "c00ae53c-1e29-4087-a384-47f3c5c1cd84",
+        "name": "Ubuntu 20.04 Focal Fossa", "organization": "11111111-1111-1111-1111-111111111111",
+        "project": "11111111-1111-1111-1111-111111111111", "root_volume": {"id": "6644dfd6-0731-45cc-a581-62f561eff7bf",
+        "name": "Ubuntu 20.04 Focal Fossa", "volume_type": "l_ssd", "size": 10000000000},
+        "extra_volumes": {}, "public": true, "arch": "x86_64", "creation_date": "2025-02-03T13:36:50.774356+00:00",
+        "modification_date": "2025-02-03T13:36:50.774356+00:00", "default_bootscript":
+        null, "from_server": "", "state": "available", "tags": [], "zone": "fr-par-1"},
+        "volumes": {"0": {"boot": false, "id": "bda6aff6-7ca2-41de-a3fb-47be986c5c0a",
+        "name": "Ubuntu 20.04 Focal Fossa", "volume_type": "l_ssd", "export_uri":
+        null, "organization": "11111111-1111-1111-1111-111111111111", "project": "11111111-1111-1111-1111-111111111111",
+        "server": {"id": "66a3b25b-4518-43c3-9e61-33b82873d617", "name": "test-sdk-python-fixture"},
+        "size": 20000000000, "state": "available", "creation_date": "2025-09-16T17:38:27.303680+00:00",
+        "modification_date": "2025-09-16T17:38:27.303680+00:00", "tags": [], "zone":
+        "fr-par-1"}}, "tags": [], "state": "stopped", "protected": false, "state_detail":
+        "", "public_ip": null, "public_ips": [], "mac_address": "de:00:00:c8:be:d7",
+        "routed_ip_enabled": true, "ipv6": null, "extra_networks": [], "dynamic_ip_required":
+        false, "enable_ipv6": false, "private_ip": null, "creation_date": "2025-09-16T17:38:27.303680+00:00",
+        "modification_date": "2025-09-16T17:38:27.303680+00:00", "bootscript": null,
+        "security_group": {"id": "1c1fc99f-b2de-408d-9eb0-da801a3e2744", "name": "Default
+        security group"}, "location": null, "maintenances": [], "allowed_actions":
+        ["poweron", "backup"], "placement_group": null, "private_nics": [], "zone":
+        "fr-par-1", "filesystems": [], "end_of_service": false}}'
+    headers:
+      content-length:
+      - '2163'
+      date:
+      - Tue, 16 Sep 2025 17:38:30 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge03)
+      x-request-id:
+      - b5cdd266-e8db-4235-9191-80b4fe13dc4b
+    status:
+      code: 200
+      message: OK
+- request:
+    body: '{}'
+    headers:
+      Content-Length:
+      - '2'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: DELETE
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617
+  response:
+    body:
+      string: ''
+    headers:
+      date:
+      - Tue, 16 Sep 2025 17:38:47 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge01)
+      x-request-id:
+      - c35b3c38-2ac3-448a-96ce-df5674242d5f
+    status:
+      code: 204
+      message: No Content
+version: 1
diff --git a/scaleway/scaleway/instance/v1/tests/cassettes/test_set_and_get_all_user_data.cassette.yaml b/scaleway/scaleway/instance/v1/tests/cassettes/test_set_and_get_all_user_data.cassette.yaml
new file mode 100644
index 000000000..98fd3ab47
--- /dev/null
+++ b/scaleway/scaleway/instance/v1/tests/cassettes/test_set_and_get_all_user_data.cassette.yaml
@@ -0,0 +1,188 @@
+interactions:
+- request:
+    body: '{}'
+    headers:
+      Content-Length:
+      - '2'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data
+  response:
+    body:
+      string: '{"user_data": ["first key"]}'
+    headers:
+      content-length:
+      - '28'
+      date:
+      - Tue, 16 Sep 2025 17:38:36 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge01)
+      x-request-id:
+      - da763635-45c0-4081-9b22-61db87a4f0a5
+    status:
+      code: 200
+      message: OK
+- request:
+    body: test content
+    headers:
+      Content-Length:
+      - '12'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: PATCH
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/second%20key
+  response:
+    body:
+      string: ''
+    headers:
+      date:
+      - Tue, 16 Sep 2025 17:38:37 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - db1aacee-4d93-4447-aaa2-562df54e2440
+    status:
+      code: 204
+      message: No Content
+- request:
+    body: another content to test
+    headers:
+      Content-Length:
+      - '23'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: PATCH
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/third%20key
+  response:
+    body:
+      string: ''
+    headers:
+      date:
+      - Tue, 16 Sep 2025 17:38:37 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - 374243f1-1d2d-4847-894a-40bfdfdc58d9
+    status:
+      code: 204
+      message: No Content
+- request:
+    body: content first key
+    headers:
+      Content-Length:
+      - '17'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: PATCH
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/first%20key
+  response:
+    body:
+      string: ''
+    headers:
+      date:
+      - Tue, 16 Sep 2025 17:38:39 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - b4a6bb3a-6c01-4f30-8cf1-4d3d2a3e25d4
+    status:
+      code: 204
+      message: No Content
+- request:
+    body: '{}'
+    headers:
+      Content-Length:
+      - '2'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data
+  response:
+    body:
+      string: '{"user_data": ["first key", "second key", "third key"]}'
+    headers:
+      content-length:
+      - '55'
+      date:
+      - Tue, 16 Sep 2025 17:38:40 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - 6bac81f0-cce6-40a6-a55e-5a920ca5aec3
+    status:
+      code: 200
+      message: OK
+- request:
+    body: '{"server_id": "66a3b25b-4518-43c3-9e61-33b82873d617", "key": "first key"}'
+    headers:
+      Content-Length:
+      - '73'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/first%20key
+  response:
+    body:
+      string: content first key
+    headers:
+      content-length:
+      - '17'
+      date:
+      - Tue, 16 Sep 2025 17:38:41 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - 3b2ad45d-108a-4867-8ea3-5c81546f7696
+    status:
+      code: 200
+      message: OK
+- request:
+    body: '{"server_id": "66a3b25b-4518-43c3-9e61-33b82873d617", "key": "second key"}'
+    headers:
+      Content-Length:
+      - '74'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/second%20key
+  response:
+    body:
+      string: test content
+    headers:
+      content-length:
+      - '12'
+      date:
+      - Tue, 16 Sep 2025 17:38:42 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - 71c301ad-28df-47d2-9c93-b76e064202f9
+    status:
+      code: 200
+      message: OK
+- request:
+    body: '{"server_id": "66a3b25b-4518-43c3-9e61-33b82873d617", "key": "third key"}'
+    headers:
+      Content-Length:
+      - '73'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/third%20key
+  response:
+    body:
+      string: another content to test
+    headers:
+      content-length:
+      - '23'
+      date:
+      - Tue, 16 Sep 2025 17:38:44 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - 557a41e4-4b5c-4f8d-95ca-fef7ba6c200c
+    status:
+      code: 200
+      message: OK
+version: 1
diff --git a/scaleway/scaleway/instance/v1/tests/cassettes/test_set_and_get_server_user_data.cassette.yaml b/scaleway/scaleway/instance/v1/tests/cassettes/test_set_and_get_server_user_data.cassette.yaml
new file mode 100644
index 000000000..af837c32e
--- /dev/null
+++ b/scaleway/scaleway/instance/v1/tests/cassettes/test_set_and_get_server_user_data.cassette.yaml
@@ -0,0 +1,48 @@
+interactions:
+- request:
+    body: this-is-a-test
+    headers:
+      Content-Length:
+      - '14'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: PATCH
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/first%20key
+  response:
+    body:
+      string: ''
+    headers:
+      date:
+      - Tue, 16 Sep 2025 17:38:32 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge01)
+      x-request-id:
+      - 0ed3c2da-9914-462b-b123-f0bd05e159e2
+    status:
+      code: 204
+      message: No Content
+- request:
+    body: '{"server_id": "66a3b25b-4518-43c3-9e61-33b82873d617", "key": "first key"}'
+    headers:
+      Content-Length:
+      - '73'
+      user-agent:
+      - scaleway-sdk-python/2.0.0
+    method: GET
+    uri: https://api.scaleway.com/instance/v1/zones/fr-par-1/servers/66a3b25b-4518-43c3-9e61-33b82873d617/user_data/first%20key
+  response:
+    body:
+      string: this-is-a-test
+    headers:
+      content-length:
+      - '14'
+      date:
+      - Tue, 16 Sep 2025 17:38:33 GMT
+      server:
+      - Scaleway API Gateway (fr-par-2;edge02)
+      x-request-id:
+      - 553413c2-2def-401d-be92-3c7e7476d070
+    status:
+      code: 200
+      message: OK
+version: 1
diff --git a/scaleway/scaleway/instance/v1/tests/test_custom_api.py b/scaleway/scaleway/instance/v1/tests/test_custom_api.py
new file mode 100644
index 000000000..2bbd86795
--- /dev/null
+++ b/scaleway/scaleway/instance/v1/tests/test_custom_api.py
@@ -0,0 +1,77 @@
+from typing import Any, Generator
+
+import pytest
+
+from scaleway.instance.v1 import Server, BootType
+from scaleway.instance.v1.custom_api import InstanceUtilsV1API
+from tests.utils import initialize_client_test
+from vcr_config import scw_vcr
+
+server_name = "test-sdk-python-fixture"
+server_name_extra = "test-sdk-python-extra"
+max_retry = 10
+interval = 0.01
+commercial_type = "DEV1-S"
+zone = "fr-par-1"
+
+# mypy: ignore-errors
+
+
+@pytest.fixture(scope="module")
+def instance_api() -> InstanceUtilsV1API:
+    client = initialize_client_test()
+    return InstanceUtilsV1API(client, bypass_validation=True)
+
+
+@pytest.fixture(scope="module")
+@scw_vcr.use_cassette
+def server(instance_api: InstanceUtilsV1API) -> Generator[Server, Any, None]:
+    instance = instance_api._create_server(
+        commercial_type=commercial_type,
+        zone=zone,
+        name=server_name,
+        dynamic_ip_required=False,
+        protected=False,
+        boot_type=BootType.LOCAL,
+        image="c00ae53c-1e29-4087-a384-47f3c5c1cd84",
+    )
+    server = instance.server
+    assert server is not None, "Server creation failed"
+    assert server.id is not None, "Server ID is None after creation"
+    instance_api.wait_instance_server(server.id, zone=zone)
+
+    yield server
+
+    instance_api.delete_server(server_id=server.id, zone=zone)
+
+
+@scw_vcr.use_cassette
+def test_set_and_get_server_user_data(
+    instance_api: InstanceUtilsV1API, server: Server
+) -> None:
+    key = "first key"
+    content = b"this-is-a-test"
+    instance_api.set_server_user_data(server.id, zone=zone, key=key, content=content)
+    user_data = instance_api.get_server_user_data(server.id, key=key)
+
+    assert user_data is not None
+
+
+@scw_vcr.use_cassette
+def test_set_and_get_all_user_data(
+    instance_api: InstanceUtilsV1API, server: Server
+) -> None:
+    key = "first key"
+    content = b"content first key"
+    key_bis = "second key"
+    content_bis = b"test content"
+    another_key = "third key"
+    another_content = b"another content to test"
+    user_data: dict[str, bytes] = {
+        key_bis: content_bis,
+        another_key: another_content,
+        key: content,
+    }
+    instance_api.set_all_server_user_data(server_id=server.id, user_data=user_data)
+    response = instance_api.get_all_server_user_data(server_id=server.id)
+    assert response.user_data == user_data