diff --git a/src/pylorax/api/errors.py b/src/pylorax/api/errors.py
new file mode 100644
index 00000000..77d7f5e2
--- /dev/null
+++ b/src/pylorax/api/errors.py
@@ -0,0 +1,21 @@
+#
+# lorax-composer API server
+#
+# Copyright (C) 2018  Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Returned from the API when ?limit= or ?offset= is given something that does
+# not convert into an integer.
+BAD_LIMIT_OR_OFFSET = "BadLimitOrOffset"
diff --git a/src/pylorax/api/v0.py b/src/pylorax/api/v0.py
index ca7b983e..4664f7ba 100644
--- a/src/pylorax/api/v0.py
+++ b/src/pylorax/api/v0.py
@@ -983,6 +983,7 @@ from pylorax.sysutils import joinpaths
 from pylorax.api.checkparams import checkparams
 from pylorax.api.compose import start_build, compose_types
 from pylorax.api.crossdomain import crossdomain
+from pylorax.api.errors import *                               # pylint: disable=wildcard-import
 from pylorax.api.projects import projects_list, projects_info, projects_depsolve
 from pylorax.api.projects import modules_list, modules_info, ProjectsError, repo_to_source
 from pylorax.api.projects import get_repo_sources, delete_repo_source, source_to_repo, dnf_repo_to_file_repo
@@ -1024,7 +1025,7 @@ def v0_api(api):
             limit = int(request.args.get("limit", "20"))
             offset = int(request.args.get("offset", "0"))
         except ValueError as e:
-            return jsonify(status=False, errors=[str(e)]), 400
+            return jsonify(status=False, errors=[{"id": BAD_LIMIT_OR_OFFSET, "msg": str(e)}]), 400
 
         with api.config["GITLOCK"].lock:
             blueprints = take_limits([f[:-5] for f in list_branch_files(api.config["GITLOCK"].repo, branch)], offset, limit)
@@ -1113,7 +1114,7 @@ def v0_api(api):
             limit = int(request.args.get("limit", "20"))
             offset = int(request.args.get("offset", "0"))
         except ValueError as e:
-            return jsonify(status=False, errors=[str(e)]), 400
+            return jsonify(status=False, errors=[{"id": BAD_LIMIT_OR_OFFSET, "msg": str(e)}]), 400
 
         blueprints = []
         errors = []
@@ -1465,7 +1466,7 @@ def v0_api(api):
             limit = int(request.args.get("limit", "20"))
             offset = int(request.args.get("offset", "0"))
         except ValueError as e:
-            return jsonify(status=False, errors=[str(e)]), 400
+            return jsonify(status=False, errors=[{"id": BAD_LIMIT_OR_OFFSET, "msg": str(e)}]), 400
 
         try:
             with api.config["DNFLOCK"].lock:
@@ -1663,7 +1664,7 @@ def v0_api(api):
             limit = int(request.args.get("limit", "20"))
             offset = int(request.args.get("offset", "0"))
         except ValueError as e:
-            return jsonify(status=False, errors=[str(e)]), 400
+            return jsonify(status=False, errors=[{"id": BAD_LIMIT_OR_OFFSET, "msg": str(e)}]), 400
 
         if module_names:
             module_names = module_names.split(",")