diff --git a/.env.demo b/.env.demo
index 7aaa0e90..6f22583a 100644
--- a/.env.demo
+++ b/.env.demo
@@ -6,6 +6,11 @@ EXTERNAL_HOSTNAME=docuelevate.example.com
 GOTENBERG_URL=http://gotenberg:3000
 ALLOW_FILE_DELETE=true  # Allow deletion of file records
 
+# **Batch Processing Settings**
+# Control throttling behavior for the /processall endpoint to prevent overwhelming downstream APIs
+PROCESSALL_THROTTLE_THRESHOLD=20  # Number of files above which throttling is applied (default: 20)
+PROCESSALL_THROTTLE_DELAY=3  # Delay in seconds between each task submission when throttling (default: 3)
+
 # **Authentication**
 AUTH_ENABLED=true
 # Generate a secure random string, for example:
diff --git a/app/api/process.py b/app/api/process.py
index 8163a7fe..e99f7d82 100644
--- a/app/api/process.py
+++ b/app/api/process.py
@@ -1,26 +1,29 @@
 """
 Document processing API endpoints
 """
-from fastapi import APIRouter, HTTPException
+
 import logging
 import os
 
+from fastapi import APIRouter, HTTPException
+
+from app.api.common import resolve_file_path
 from app.auth import require_login
 from app.config import settings
-from app.api.common import resolve_file_path
 from app.tasks.process_document import process_document
-from app.tasks.upload_to_dropbox import upload_to_dropbox
-from app.tasks.upload_to_paperless import upload_to_paperless
-from app.tasks.upload_to_nextcloud import upload_to_nextcloud
-from app.tasks.upload_to_google_drive import upload_to_google_drive
-from app.tasks.upload_to_onedrive import upload_to_onedrive
 from app.tasks.send_to_all import send_to_all_destinations
+from app.tasks.upload_to_dropbox import upload_to_dropbox
+from app.tasks.upload_to_google_drive import upload_to_google_drive
+from app.tasks.upload_to_nextcloud import upload_to_nextcloud
+from app.tasks.upload_to_onedrive import upload_to_onedrive
+from app.tasks.upload_to_paperless import upload_to_paperless
 
 # Set up logging
 logger = logging.getLogger(__name__)
 
 router = APIRouter()
 
+
 @router.post("/process/")
 @require_login
 def process(file_path: str):
@@ -28,96 +31,92 @@ def process(file_path: str):
     file_path = resolve_file_path(file_path)
 
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
 
     task = process_document.delay(file_path)
     return {"task_id": task.id, "status": "queued"}
 
+
 @router.post("/send_to_dropbox/")
 @require_login
 def send_to_dropbox_endpoint(file_path: str):
     """Send a document to Dropbox."""
-    file_path = resolve_file_path(file_path, 'processed')
+    file_path = resolve_file_path(file_path, "processed")
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
     task = upload_to_dropbox.delay(file_path)
     return {"task_id": task.id, "status": "queued"}
 
+
 @router.post("/send_to_paperless/")
 @require_login
 def send_to_paperless_endpoint(file_path: str):
     """Send a document to Paperless-ngx."""
-    file_path = resolve_file_path(file_path, 'processed')
+    file_path = resolve_file_path(file_path, "processed")
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
     task = upload_to_paperless.delay(file_path)
     return {"task_id": task.id, "status": "queued"}
 
+
 @router.post("/send_to_nextcloud/")
 @require_login
 def send_to_nextcloud_endpoint(file_path: str):
     """Send a document to NextCloud."""
-    file_path = resolve_file_path(file_path, 'processed')
+    file_path = resolve_file_path(file_path, "processed")
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
     task = upload_to_nextcloud.delay(file_path)
     return {"task_id": task.id, "status": "queued"}
 
+
 @router.post("/send_to_google_drive/")
 @require_login
 def send_to_google_drive_endpoint(file_path: str):
     """Send a document to Google Drive."""
-    file_path = resolve_file_path(file_path, 'processed')
+    file_path = resolve_file_path(file_path, "processed")
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
     task = upload_to_google_drive.delay(file_path)
     return {"task_id": task.id, "status": "queued"}
 
+
 @router.post("/send_to_onedrive/")
 @require_login
 def send_to_onedrive_endpoint(file_path: str):
     """Send a document to OneDrive."""
-    file_path = resolve_file_path(file_path, 'processed')
+    file_path = resolve_file_path(file_path, "processed")
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
     task = upload_to_onedrive.delay(file_path)
     return {"task_id": task.id, "status": "queued"}
 
+
 @router.post("/send_to_all_destinations/")
 @require_login
 def send_to_all_destinations_endpoint(file_path: str):
     """Call the aggregator task that sends this file to all configured destinations."""
-    file_path = resolve_file_path(file_path, 'processed')
+    file_path = resolve_file_path(file_path, "processed")
 
     if not os.path.exists(file_path):
-        raise HTTPException(
-            status_code=400, detail=f"File {file_path} not found."
-        )
+        raise HTTPException(status_code=400, detail=f"File {file_path} not found.")
 
     task = send_to_all_destinations.delay(file_path)
     return {"task_id": task.id, "status": "queued", "file_path": file_path}
 
+
 @router.post("/processall")
 @require_login
 def process_all_pdfs_in_workdir():
-    """Finds all .pdf files in <workdir> and enqueues them for processing."""
+    """
+    Finds all .pdf files in <workdir> and enqueues them for processing.
+
+    For large batches (>processall_throttle_threshold files), tasks are staggered
+    to avoid overwhelming downstream APIs.
+    """
     target_dir = settings.workdir
     if not os.path.exists(target_dir):
-        raise HTTPException(
-            status_code=400, detail=f"Directory {target_dir} does not exist."
-        )
+        raise HTTPException(status_code=400, detail=f"Directory {target_dir} does not exist.")
 
     pdf_files = []
     for filename in os.listdir(target_dir):
@@ -128,13 +127,37 @@ def process_all_pdfs_in_workdir():
         return {"message": "No PDF files found in that directory."}
 
     task_ids = []
-    for pdf in pdf_files:
+    num_files = len(pdf_files)
+
+    # Apply throttling if we have more files than the threshold
+    apply_throttle = num_files > settings.processall_throttle_threshold
+
+    if apply_throttle:
+        logger.info(
+            f"Processing {num_files} files with throttling "
+            f"(threshold: {settings.processall_throttle_threshold}, "
+            f"delay: {settings.processall_throttle_delay}s per file)"
+        )
+
+    for index, pdf in enumerate(pdf_files):
         file_path = os.path.join(target_dir, pdf)
-        task = process_document.delay(file_path)
+
+        if apply_throttle:
+            # Stagger task submission with countdown
+            # First file starts immediately (countdown=0)
+            # Each subsequent file has an increasing delay
+            countdown = index * settings.processall_throttle_delay
+            task = process_document.apply_async(args=[file_path], countdown=countdown)
+            logger.debug(f"Scheduled {pdf} with {countdown}s delay")
+        else:
+            # No throttling - enqueue immediately
+            task = process_document.delay(file_path)
+
         task_ids.append(task.id)
 
-    return {
-        "message": f"Enqueued {len(pdf_files)} PDFs to upload_to_s3",
-        "pdf_files": pdf_files,
-        "task_ids": task_ids
-    }
+    message = f"Enqueued {num_files} PDFs for processing"
+    if apply_throttle:
+        total_time = (num_files - 1) * settings.processall_throttle_delay
+        message += f" (throttled over {total_time} seconds)"
+
+    return {"message": message, "pdf_files": pdf_files, "task_ids": task_ids, "throttled": apply_throttle}
diff --git a/app/config.py b/app/config.py
index b723b74e..b9e7fc96 100644
--- a/app/config.py
+++ b/app/config.py
@@ -1,10 +1,12 @@
 #!/usr/bin/env python3
 
-from pydantic_settings import BaseSettings
-from typing import Optional, List, Dict, Any, Union
-from pydantic import Field, validator
 import os
 from datetime import datetime
+from typing import Any, Dict, List, Optional, Union
+
+from pydantic import Field, validator
+from pydantic_settings import BaseSettings
+
 
 class Settings(BaseSettings):
     database_url: str
@@ -14,23 +16,23 @@ class Settings(BaseSettings):
     openai_model: str = "gpt-4o-mini"  # Default model
     workdir: str
     debug: bool = False  # Default to False
-    
+
     # Making Dropbox optional
     dropbox_app_key: Optional[str] = None
     dropbox_app_secret: Optional[str] = None
     dropbox_folder: Optional[str] = None
     dropbox_refresh_token: Optional[str] = None
-    
+
     # Making Nextcloud optional
     nextcloud_upload_url: Optional[str] = None
     nextcloud_username: Optional[str] = None
     nextcloud_password: Optional[str] = None
     nextcloud_folder: Optional[str] = None
-    
+
     # Making Paperless optional
     paperless_ngx_api_token: Optional[str] = None
     paperless_host: Optional[str] = None
-    
+
     azure_ai_key: str
     azure_region: str
     azure_endpoint: str
@@ -71,7 +73,7 @@ class Settings(BaseSettings):
     google_drive_credentials_json: Optional[str] = ""
     google_drive_folder_id: Optional[str] = ""
     google_drive_delegate_to: Optional[str] = ""  # Optional delegated user email
-    
+
     # Google Drive OAuth settings
     google_drive_use_oauth: bool = False  # Default to service account method
     google_drive_client_id: Optional[str] = ""
@@ -135,49 +137,45 @@ class Settings(BaseSettings):
     # Feature flags
     allow_file_delete: bool = True  # Default to allowing file deletion from database
 
+    # Batch processing settings
+    processall_throttle_threshold: int = Field(
+        default=20, description="Number of files above which throttling is applied in /processall endpoint"
+    )
+    processall_throttle_delay: int = Field(
+        default=3, description="Delay in seconds between each task submission when throttling in /processall"
+    )
+
     # Notification settings
     notification_urls: Union[List[str], str] = Field(
-        default_factory=list,
-        description="List of Apprise notification URLs (e.g., discord://, telegram://, etc.)"
-    )
-    notify_on_task_failure: bool = Field(
-        default=True, 
-        description="Send notifications when Celery tasks fail"
+        default_factory=list, description="List of Apprise notification URLs (e.g., discord://, telegram://, etc.)"
     )
+    notify_on_task_failure: bool = Field(default=True, description="Send notifications when Celery tasks fail")
     notify_on_credential_failure: bool = Field(
-        default=True,
-        description="Send notifications when credential checks fail"
-    )
-    notify_on_startup: bool = Field(
-        default=True,
-        description="Send notifications when application starts"
-    )
-    notify_on_shutdown: bool = Field(
-        default=False,
-        description="Send notifications when application shuts down"
+        default=True, description="Send notifications when credential checks fail"
     )
+    notify_on_startup: bool = Field(default=True, description="Send notifications when application starts")
+    notify_on_shutdown: bool = Field(default=False, description="Send notifications when application shuts down")
     notify_on_file_processed: bool = Field(
-        default=True,
-        description="Send notifications when files are successfully processed"
+        default=True, description="Send notifications when files are successfully processed"
     )
-    
-    @validator('notification_urls', pre=True)
+
+    @validator("notification_urls", pre=True)
     def parse_notification_urls(cls, v):
         """Parse notification URLs from string or list"""
         if isinstance(v, str):
-            if ',' in v:
-                return [url.strip() for url in v.split(',') if url.strip()]
+            if "," in v:
+                return [url.strip() for url in v.split(",") if url.strip()]
             elif v.strip():
                 return [v.strip()]
             return []
         return v
 
-    @validator('session_secret')
+    @validator("session_secret")
     def validate_session_secret(cls, v, values):
         """Validate that session_secret is set and has sufficient length when auth is enabled"""
-        if values.get('auth_enabled') and not v:
+        if values.get("auth_enabled") and not v:
             raise ValueError("SESSION_SECRET must be set when AUTH_ENABLED=True")
-        if values.get('auth_enabled') and v and len(v) < 32:
+        if values.get("auth_enabled") and v and len(v) < 32:
             raise ValueError("SESSION_SECRET must be at least 32 characters long")
         return v
 
@@ -188,13 +186,13 @@ class Settings(BaseSettings):
         env_build_date = os.environ.get("BUILD_DATE")
         if env_build_date:
             return env_build_date
-        
+
         # Then try to get build date from BUILD_DATE file
         build_date_file = os.path.join(os.path.dirname(os.path.dirname(__file__)), "BUILD_DATE")
         if os.path.exists(build_date_file):
             with open(build_date_file, "r") as f:
                 return f.read().strip()
-        
+
         # Default to unknown if not found
         return "Unknown build date"
 
@@ -205,35 +203,38 @@ class Settings(BaseSettings):
         env_version = os.environ.get("APP_VERSION")
         if env_version:
             return env_version
-        
+
         # Then try to get version from VERSION file
         version_file = os.path.join(os.path.dirname(os.path.dirname(__file__)), "VERSION")
         if os.path.exists(version_file):
             with open(version_file, "r") as f:
                 return f.read().strip()
-                
+
         # Default version if not found
         return "0.3.2-dev"
 
     class Config:
         env_file = ".env"
+
         # Convert string representations of booleans to actual booleans
         # and strip quotes from string values
         @classmethod
         def parse_env_var(cls, field_name: str, raw_val: str) -> Any:
             # First, strip quotes from the value if it's a string
             if isinstance(raw_val, str):
-                if (raw_val.startswith('"') and raw_val.endswith('"')) or \
-                   (raw_val.startswith("'") and raw_val.endswith("'")):
+                if (raw_val.startswith('"') and raw_val.endswith('"')) or (
+                    raw_val.startswith("'") and raw_val.endswith("'")
+                ):
                     raw_val = raw_val[1:-1]
                 raw_val = raw_val.strip()
-                
+
             # Convert string representations of booleans to actual booleans
-            if field_name.endswith('_enabled') or field_name == 'debug':
-                if raw_val.lower() in ('false', '0', 'no', 'n', 'f'):
+            if field_name.endswith("_enabled") or field_name == "debug":
+                if raw_val.lower() in ("false", "0", "no", "n", "f"):
                     return False
-                if raw_val.lower() in ('true', '1', 'yes', 'y', 't'):
+                if raw_val.lower() in ("true", "1", "yes", "y", "t"):
                     return True
             return raw_val
 
+
 settings = Settings()
diff --git a/docs/API.md b/docs/API.md
index f113731b..45636a13 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -101,6 +101,29 @@ Reprocess a specific file.
 }
 ```
 
+### Batch Processing
+
+**POST** `/api/processall`
+
+Process all PDF files in the configured workdir directory.
+
+**Throttling**: For large batches (>20 files by default), tasks are automatically staggered to prevent overwhelming downstream APIs. The throttling behavior can be configured via environment variables:
+
+- `PROCESSALL_THROTTLE_THRESHOLD`: Number of files above which throttling is applied (default: 20)
+- `PROCESSALL_THROTTLE_DELAY`: Delay in seconds between each task submission when throttling (default: 3)
+
+**Example**: When processing 25 files with default settings, the first file is queued immediately, the second after 3 seconds, the third after 6 seconds, etc., spreading the load over 72 seconds total.
+
+**Response**:
+```json
+{
+  "message": "Enqueued 25 PDFs for processing (throttled over 72 seconds)",
+  "pdf_files": ["file1.pdf", "file2.pdf", ...],
+  "task_ids": ["a1b2c3...", "d4e5f6...", ...],
+  "throttled": true
+}
+```
+
 **POST** `/send_to_google_drive/`
 
 Send a processed file to Google Drive.
diff --git a/docs/ConfigurationGuide.md b/docs/ConfigurationGuide.md
index 04fc0edb..0aef4ee6 100644
--- a/docs/ConfigurationGuide.md
+++ b/docs/ConfigurationGuide.md
@@ -17,6 +17,20 @@ Configuration is primarily done through environment variables specified in a `.e
 | `EXTERNAL_HOSTNAME`    | The external hostname for the application.             | `docuelevate.example.com`      |
 | `ALLOW_FILE_DELETE`    | Enable file deletion in the web interface (`true`/`false`). | `true`                      |
 
+### Batch Processing Settings
+
+Control how the `/processall` endpoint handles large batches of files to prevent overwhelming downstream APIs.
+
+| **Variable**                      | **Description**                                                                                    | **Default** |
+|-----------------------------------|----------------------------------------------------------------------------------------------------|-------------|
+| `PROCESSALL_THROTTLE_THRESHOLD`   | Number of files above which throttling is applied. Files <= threshold are processed immediately.  | `20`        |
+| `PROCESSALL_THROTTLE_DELAY`       | Delay in seconds between each task submission when throttling is active.                          | `3`         |
+
+**Example Usage**: When processing 25 files with default settings:
+- Files are staggered: file 0 at 0s, file 1 at 3s, file 2 at 6s, etc.
+- Total queue time: (25-1) × 3 = 72 seconds
+- Prevents API rate limit issues and ensures smooth processing
+
 ### IMAP Configuration
 
 DocuElevate can monitor multiple IMAP mailboxes for document attachments. Each mailbox uses a numbered prefix (e.g., `IMAP1_`, `IMAP2_`).
diff --git a/tests/conftest.py b/tests/conftest.py
index 4e80504d..2b949b50 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -70,7 +70,8 @@ def client(db_session) -> TestClient:
     
     fastapi_app.dependency_overrides[get_db] = override_get_db
     
-    with TestClient(fastapi_app) as test_client:
+    # Use base_url to satisfy TrustedHostMiddleware
+    with TestClient(fastapi_app, base_url="http://localhost") as test_client:
         yield test_client
     
     # Clean up
diff --git a/tests/test_processall_throttling.py b/tests/test_processall_throttling.py
new file mode 100644
index 00000000..5b2d65b8
--- /dev/null
+++ b/tests/test_processall_throttling.py
@@ -0,0 +1,241 @@
+"""
+Tests for /processall endpoint throttling behavior.
+"""
+
+import os
+from unittest.mock import MagicMock, Mock, patch
+
+import pytest
+from fastapi.testclient import TestClient
+
+
+@pytest.fixture
+def mock_throttle_settings(monkeypatch):
+    """Fixture to configure throttle settings for tests."""
+
+    def _configure(workdir, threshold=20, delay=3):
+        from app.api import process
+
+        monkeypatch.setattr(process.settings, "workdir", str(workdir))
+        monkeypatch.setattr(process.settings, "processall_throttle_threshold", threshold)
+        monkeypatch.setattr(process.settings, "processall_throttle_delay", delay)
+
+    return _configure
+
+
+@pytest.mark.integration
+class TestProcessAllThrottling:
+    """Tests for processall endpoint with throttling."""
+
+    @patch("app.api.process.process_document")
+    def test_processall_no_throttling_for_small_batch(
+        self, mock_task, client: TestClient, tmp_path, mock_throttle_settings
+    ):
+        """Test that small batches (<=20 files) are not throttled."""
+        # Create test directory with 10 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+
+        for i in range(10):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+
+        # Mock the task
+        mock_task.delay = Mock(return_value=Mock(id="task-id"))
+        mock_task.apply_async = Mock(return_value=Mock(id="task-id"))
+
+        # Configure settings
+        mock_throttle_settings(workdir, threshold=20, delay=3)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 200
+        data = response.json()
+
+        # Should use .delay() (not throttled)
+        assert mock_task.delay.call_count == 10
+        assert mock_task.apply_async.call_count == 0
+
+        # Response should indicate no throttling
+        assert data["throttled"] is False
+        assert len(data["pdf_files"]) == 10
+        assert len(data["task_ids"]) == 10
+
+    @patch("app.api.process.process_document")
+    def test_processall_throttling_for_large_batch(
+        self, mock_task, client: TestClient, tmp_path, mock_throttle_settings
+    ):
+        """Test that large batches (>20 files) are throttled."""
+        # Create test directory with 25 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+
+        for i in range(25):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+
+        # Mock the task
+        mock_task_result = Mock(id="task-id")
+        mock_task.apply_async = Mock(return_value=mock_task_result)
+
+        # Configure settings
+        mock_throttle_settings(workdir, threshold=20, delay=3)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 200
+        data = response.json()
+
+        # Should use .apply_async() with countdown (throttled)
+        assert mock_task.apply_async.call_count == 25
+
+        # Verify countdown values are increasing
+        calls = mock_task.apply_async.call_args_list
+        for i, call_args in enumerate(calls):
+            expected_countdown = i * 3  # 3 seconds delay
+            assert call_args[1]["countdown"] == expected_countdown
+
+        # Response should indicate throttling
+        assert data["throttled"] is True
+        assert len(data["pdf_files"]) == 25
+        assert len(data["task_ids"]) == 25
+        assert "throttled over" in data["message"]
+
+    @patch("app.api.process.process_document")
+    def test_processall_exactly_at_threshold(self, mock_task, client: TestClient, tmp_path, mock_throttle_settings):
+        """Test behavior when file count equals threshold."""
+        # Create test directory with exactly 20 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+
+        for i in range(20):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+
+        # Mock the task
+        mock_task.delay = Mock(return_value=Mock(id="task-id"))
+
+        # Configure settings
+        mock_throttle_settings(workdir, threshold=20, delay=3)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 200
+        data = response.json()
+
+        # At threshold, should NOT throttle (only >threshold)
+        assert mock_task.delay.call_count == 20
+        assert data["throttled"] is False
+
+    @patch("app.api.process.process_document")
+    def test_processall_one_over_threshold(self, mock_task, client: TestClient, tmp_path, mock_throttle_settings):
+        """Test that throttling activates at threshold + 1."""
+        # Create test directory with 21 PDF files (threshold is 20)
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+
+        for i in range(21):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+
+        # Mock the task
+        mock_task.apply_async = Mock(return_value=Mock(id="task-id"))
+
+        # Configure settings
+        mock_throttle_settings(workdir, threshold=20, delay=3)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 200
+        data = response.json()
+
+        # Should be throttled
+        assert mock_task.apply_async.call_count == 21
+        assert data["throttled"] is True
+
+    def test_processall_empty_directory(self, client: TestClient, tmp_path, mock_throttle_settings):
+        """Test processall with no PDF files."""
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+
+        # Configure settings
+        mock_throttle_settings(workdir)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["message"] == "No PDF files found in that directory."
+
+    def test_processall_nonexistent_directory(self, client: TestClient, tmp_path, mock_throttle_settings):
+        """Test processall with non-existent directory."""
+        workdir = tmp_path / "nonexistent"
+
+        # Configure settings
+        mock_throttle_settings(workdir)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 400
+        data = response.json()
+        assert "does not exist" in data["detail"]
+
+    @patch("app.api.process.process_document")
+    def test_processall_custom_threshold(self, mock_task, client: TestClient, tmp_path, mock_throttle_settings):
+        """Test that custom threshold value is respected."""
+        # Create test directory with 15 PDF files
+        workdir = tmp_path / "workdir"
+        workdir.mkdir()
+
+        for i in range(15):
+            (workdir / f"test{i}.pdf").write_text("dummy pdf content")
+
+        # Mock the task
+        mock_task.apply_async = Mock(return_value=Mock(id="task-id"))
+
+        # Configure settings with lower threshold
+        mock_throttle_settings(workdir, threshold=10, delay=2)
+
+        response = client.post("/api/processall")
+
+        assert response.status_code == 200
+        data = response.json()
+
+        # Should be throttled because 15 > 10
+        assert mock_task.apply_async.call_count == 15
+        assert data["throttled"] is True
+
+
+@pytest.mark.unit
+class TestThrottlingConfiguration:
+    """Tests for throttling configuration settings."""
+
+    def test_default_throttle_threshold(self):
+        """Test that default threshold is 20."""
+        from app.config import Settings
+
+        settings = Settings(
+            database_url="sqlite:///test.db",
+            redis_url="redis://localhost",
+            openai_api_key="test-key",
+            workdir="/tmp",
+            azure_ai_key="test-key",
+            azure_region="test-region",
+            azure_endpoint="https://test.endpoint",
+            gotenberg_url="http://gotenberg",
+            session_secret="a" * 32,
+        )
+        assert settings.processall_throttle_threshold == 20
+
+    def test_default_throttle_delay(self):
+        """Test that default delay is 3 seconds."""
+        from app.config import Settings
+
+        settings = Settings(
+            database_url="sqlite:///test.db",
+            redis_url="redis://localhost",
+            openai_api_key="test-key",
+            workdir="/tmp",
+            azure_ai_key="test-key",
+            azure_region="test-region",
+            azure_endpoint="https://test.endpoint",
+            gotenberg_url="http://gotenberg",
+            session_secret="a" * 32,
+        )
+        assert settings.processall_throttle_delay == 3