diff --git a/runbot_merge/controllers/__init__.py b/runbot_merge/controllers/__init__.py
index a2f6c196..c37b3d3f 100644
--- a/runbot_merge/controllers/__init__.py
+++ b/runbot_merge/controllers/__init__.py
@@ -8,6 +8,7 @@ from datetime import datetime, timedelta
 from typing import Callable
 
 import sentry_sdk
+from werkzeug.exceptions import NotFound, UnprocessableEntity
 
 from odoo.api import Environment
 from odoo.http import Controller, request, route, Response
@@ -18,40 +19,56 @@ from .. import utils, github
 
 _logger = logging.getLogger(__name__)
 
+def staging_dict(staging):
+    return {
+        'id': staging.id,
+        'pull_requests': staging.batch_ids.prs.mapped(lambda p: {
+            'name': p.display_name,
+            'repository': p.repository.name,
+            'number': p.number,
+        }),
+        'merged': staging.commit_ids.mapped('sha'),
+        'staged': staging.head_ids.mapped('sha'),
+    }
+
 class MergebotController(Controller):
-    @route('/runbot_merge/stagings', auth='none', type='json')
-    def stagings_for_commits(self, commits=None, heads=None):
-        Stagings = request.env(user=1)['runbot_merge.stagings'].sudo()
-        if commits:
-            stagings = Stagings.for_commits(*commits)
-        elif heads:
-            stagings = Stagings.for_heads(*heads)
+    @route('/runbot_merge/stagings', auth='none', type='http', methods=['GET'])
+    def stagings_for_commits(self, **kw):
+        commits = request.httprequest.args.getlist('merged')
+        heads = request.httprequest.args.getlist('staged')
+        if bool(commits) ^ bool(heads):
+            Stagings = request.env(user=1)['runbot_merge.stagings'].sudo()
+            if commits:
+                stagings = Stagings.for_commits(*commits)
+            else:
+                stagings = Stagings.for_heads(*heads)
+
+            # can pass `?state=` to get stagings in any state
+            if state := request.httprequest.args.get('state', 'success'):
+                stagings = stagings.filtered(lambda s: s.state == state)
+            return request.make_json_response(stagings.mapped(staging_dict))
         else:
-            raise ValueError('Must receive one of "commits" or "heads" kwarg')
+            raise UnprocessableEntity("Must receive either `merged` or `staged` query parameters (can receive multiple of either)")
 
-        return stagings.ids
-
-    @route('/runbot_merge/stagings/<int:staging>', auth='none', type='json')
+    @route('/runbot_merge/stagings/<int:staging>', auth='none', type='http', methods=['GET'])
     def prs_for_staging(self, staging):
-        staging = request.env(user=1)['runbot_merge.stagings'].browse(staging)
-        return [
-            batch.prs.mapped(lambda p: {
-                'name': p.display_name,
-                'repository': p.repository.name,
-                'number': p.number,
-            })
-            for batch in staging.sudo().batch_ids
-        ]
+        staging = request.env(user=1)['runbot_merge.stagings'].browse(staging).sudo()
+        if not staging.exists:
+            raise NotFound()
 
-    @route('/runbot_merge/stagings/<int:from_staging>/<int:to_staging>', auth='none', type='json')
-    def prs_for_stagings(self, from_staging, to_staging, include_from=True, include_to=True):
+        return request.make_json_response(staging_dict(staging))
+
+    @route('/runbot_merge/stagings/<int:from_staging>/<int:to_staging>', auth='none', type='http', methods=['GET'])
+    def prs_for_stagings(self, from_staging, to_staging, include_from='1', include_to='1'):
         Stagings = request.env(user=1, context={"active_test": False})['runbot_merge.stagings']
         from_staging = Stagings.browse(from_staging)
         to_staging = Stagings.browse(to_staging)
+        if not (from_staging.exists() and to_staging.exists()):
+            raise NotFound()
         if from_staging.target != to_staging.target:
-            raise ValueError(f"Stagings must have the same target branch, found {from_staging.target.name} and {to_staging.target.name}")
+            raise UnprocessableEntity(f"Stagings must have the same target branch, found {from_staging.target.name} and {to_staging.target.name}")
         if from_staging.id >= to_staging.id:
-            raise ValueError("first staging must be older than second staging")
+            raise UnprocessableEntity("first staging must be older than second staging")
 
         stagings = Stagings.search([
             ('target', '=', to_staging.target.id),
@@ -60,20 +77,7 @@ class MergebotController(Controller):
             ('id', '<=' if include_to else '<', to_staging.id),
         ], order="id asc")
 
-        return [
-            {
-                'staging': staging.id,
-                'prs': [
-                    batch.prs.mapped(lambda p: {
-                        'name': p.display_name,
-                        'repository': p.repository.name,
-                        'number': p.number,
-                    })
-                    for batch in staging.batch_ids
-                ]
-            }
-            for staging in stagings
-        ]
+        return request.make_json_response([staging_dict(staging) for staging in stagings])
 
     @route('/runbot_merge/hooks', auth='none', type='http', csrf=False, methods=['POST'])
     def index(self) -> Response: