diff --git a/src/scitacean/testing/backend/_backend.py b/src/scitacean/testing/backend/_backend.py
index 866666fa..ecf3309e 100644
--- a/src/scitacean/testing/backend/_backend.py
+++ b/src/scitacean/testing/backend/_backend.py
@@ -4,6 +4,7 @@
 import os
 import time
 from copy import deepcopy
+from pathlib import Path
 from typing import Any, Dict, Union
 from urllib.parse import urljoin
 
@@ -35,7 +36,9 @@ def _docker_compose_template() -> Dict[str, Any]:
     return template  # type: ignore[no-any-return]
 
 
-def _apply_config(template: Dict[str, Any]) -> Dict[str, Any]:
+def _apply_config(
+    template: Dict[str, Any], account_config_path: Path
+) -> Dict[str, Any]:
     res = deepcopy(template)
     scicat = res["services"]["scicat"]
     ports = scicat["ports"][0].split(":")
@@ -46,6 +49,10 @@ def _apply_config(template: Dict[str, Any]) -> Dict[str, Any]:
     env["PID_PREFIX"] = config.PID_PREFIX
     env["SITE"] = config.SITE
 
+    scicat["volumes"] = [
+        f"/home/node/app/functionalAccounts.json:{account_config_path}",
+    ]
+
     return res
 
 
@@ -57,7 +64,9 @@ def configure(target_path: _PathLike) -> None:
     target_path:
         Generate a docker-compose file at this path.
     """
-    c = yaml.dump(_apply_config(_docker_compose_template()))
+    account_config_path = Path(target_path).parent / "functionalAccounts.json"
+    config.dump_account_config(account_config_path)
+    c = yaml.dump(_apply_config(_docker_compose_template(), account_config_path))
     if "PLACEHOLDER" in c:
         raise RuntimeError("Incorrect config")
 
diff --git a/src/scitacean/testing/backend/config.py b/src/scitacean/testing/backend/config.py
index 387269c3..e800f8ba 100644
--- a/src/scitacean/testing/backend/config.py
+++ b/src/scitacean/testing/backend/config.py
@@ -2,8 +2,9 @@
 # Copyright (c) 2024 SciCat Project (https://github.com/SciCatProject/scitacean)
 """Backend configuration."""
 
+import json
 from dataclasses import dataclass
-from typing import Dict
+from pathlib import Path
 
 
 @dataclass
@@ -23,7 +24,7 @@ class SciCatUser:
     group: str
 
     @property
-    def credentials(self) -> Dict[str, str]:
+    def credentials(self) -> dict[str, str]:
         """Return login credentials for this user.
 
         User as
@@ -37,6 +38,16 @@ def credentials(self) -> Dict[str, str]:
             "password": self.password,
         }
 
+    def dump(self) -> dict[str, str]:
+        """Return a dict that can be serialized to functionalAccounts.json."""
+        return {
+            "username": self.username,
+            "password": self.password,
+            "email": self.email,
+            "role": self.group,
+            "global": False,
+        }
+
 
 # see https://github.com/SciCatProject/scicat-backend-next/blob/master/src/config/configuration.ts
 USERS = {
@@ -116,3 +127,9 @@ def local_access(user: str) -> SciCatAccess:
         Parameters for the local SciCat backend.
     """
     return SciCatAccess(url=f"http://localhost:{SCICAT_PORT}/api/v3/", user=USERS[user])
+
+
+def dump_account_config(path: Path) -> None:
+    """Write a functional account config for the backend."""
+    with path.open("w") as f:
+        json.dump([user.dump() for user in USERS.values()], f)