diff --git a/app/routes/backup.py b/app/routes/backup.py
index d1b171a..d697f40 100644
--- a/app/routes/backup.py
+++ b/app/routes/backup.py
@@ -9,10 +9,12 @@ Created by: Jess Rogerson (yelling commands at Claude.AI)
 """
 
 import os
+from datetime import datetime
 
 from flask import (Blueprint, render_template, redirect, url_for, flash,
                    request, jsonify, send_file, current_app, abort)
 from flask_login import login_required, current_user
+from werkzeug.utils import secure_filename
 
 from app.routes.admin import admin_required
 from app.services import backup_service as bsvc
@@ -50,6 +52,7 @@ def index():
         dialect=bsvc.database_dialect(),
         sqlite_path=bsvc.sqlite_db_path(),
         keep=current_app.config.get('BACKUP_KEEP'),
+        max_upload=current_app.config.get('BACKUP_MAX_UPLOAD'),
     )
 
 
@@ -110,6 +113,92 @@ def verify(filename):
     })
 
 
+@backup_bp.route('/upload', methods=['POST'])
+@login_required
+@admin_required
+def upload():
+    """
+    Receive a backup archive as the raw request body and stream it to disk.
+
+    Deliberately NOT a multipart form. Flask enforces MAX_CONTENT_LENGTH (50MB)
+    whenever the form parser runs, and its value cannot be overridden per
+    request — the property reads app config every time. Reading the WSGI input
+    stream directly sidesteps the parser, so a multi-gigabyte archive uploads
+    without raising the global limit for every other upload in the app. It also
+    avoids Werkzeug spooling the whole file into a temp copy first.
+
+    The browser sends: POST /admin/backup/upload?filename=<name>.zip
+    with the file itself as the body.
+    """
+    raw_name = request.args.get('filename', '')
+    safe = secure_filename(os.path.basename(raw_name))
+    if not safe.lower().endswith('.zip'):
+        return jsonify({'error': 'Filename must end in .zip'}), 400
+
+    folder = bsvc.backup_folder()
+
+    # Don't clobber an existing archive.
+    target = os.path.join(folder, safe)
+    if os.path.exists(target):
+        stem, ext = os.path.splitext(safe)
+        safe = f"{stem}-uploaded-{datetime.now().strftime('%Y%m%d-%H%M%S')}{ext}"
+        target = os.path.join(folder, safe)
+
+    limit = current_app.config.get('BACKUP_MAX_UPLOAD') or 0
+    declared = request.content_length or 0
+    if limit and declared > limit:
+        return jsonify({'error': f'Archive exceeds the {limit} byte upload limit'}), 413
+
+    stream = request.environ.get('wsgi.input')
+    if stream is None:
+        return jsonify({'error': 'No request body'}), 400
+
+    partial = target + '.part'
+    written = 0
+    try:
+        with open(partial, 'wb') as handle:
+            while True:
+                if declared and written >= declared:
+                    break
+                chunk = stream.read(1024 * 1024)
+                if not chunk:
+                    break
+                written += len(chunk)
+                if limit and written > limit:
+                    raise ValueError(f'Archive exceeds the {limit} byte upload limit')
+                handle.write(chunk)
+
+        if written == 0:
+            raise ValueError('Uploaded file was empty')
+
+        # Only keep it if it actually is one of ours.
+        manifest = bsvc.read_manifest(partial)
+        if manifest.get('format') != bsvc.BACKUP_FORMAT:
+            raise ValueError('Not a LIM backup archive')
+
+        os.replace(partial, target)
+
+    except Exception as exc:  # noqa: BLE001 - reported to the admin
+        if os.path.exists(partial):
+            try:
+                os.remove(partial)
+            except OSError:
+                pass
+        current_app.logger.warning('Backup upload rejected: %s', exc)
+        return jsonify({'error': str(exc)}), 400
+
+    current_app.logger.info('Backup uploaded: %s (%d bytes)', safe, written)
+    return jsonify({
+        'filename': safe,
+        'size_bytes': written,
+        'size_human': bsvc.human_size(written),
+        'counts': manifest.get('counts', {}),
+        'uploads': manifest.get('uploads', {}),
+        'created_at': manifest.get('created_at'),
+        'source': manifest.get('source', {}).get('hostname'),
+    })
+
+
 @backup_bp.route('/delete/<path:filename>', methods=['POST'])
 @login_required
 @admin_required