diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -12,6 +12,7 @@
 import subprocess
 
 from setuptools import find_packages, setup
+from setuptools.command.develop import develop
 from setuptools.command.sdist import sdist
 
 here = os.path.abspath(os.path.dirname(__file__))
@@ -76,7 +77,7 @@
 
         ql_dir = os.path.join(self.build_lib, "swh/search/query_language")
         if not os.path.exists(os.path.join(ql_dir, "src/parser.c")):
-            generate_parser(ql_dir)
+            generate_parser(ql_dir, copy_tree=True)
 
         static_dir = os.path.join(self.build_lib, "swh/search/static")
         os.makedirs(static_dir, exist_ok=True)
@@ -89,14 +90,6 @@
         print("swh_ql.so file generated")
 
 
-class TSBuildWasmCommand(TSCommand):
-    description = "Builds swh_ql.wasm"
-
-    def run(self):
-        subprocess.run([yarn, "build-wasm"], check=True)
-        print("swh_ql.wasm file generated")
-
-
 class TSBuildCommand(TSCommand):
     description = "Builds swh_ql.so and swh_ql.wasm"
 
@@ -121,15 +114,24 @@
         if not self.dry_run:
             self.run_command("ts_install")
 
-            generate_parser(dist_ql_path)
+            generate_parser(dist_ql_path, copy_tree=True)
+
+
+class custom_develop(develop):
+    def run(self):
+        super().run()
+
+        if not self.dry_run:
+            generate_parser("swh/search/query_language", copy_tree=False)
 
 
-def generate_parser(dest_path):
-    # FIXME: setuptools should copy this itself...
-    print("Copying parser files")
-    if os.path.exists(dest_path):
-        shutil.rmtree(dest_path)
-    shutil.copytree("swh/search/query_language", dest_path)
+def generate_parser(dest_path, copy_tree):
+    if copy_tree:
+        # FIXME: setuptools should copy this itself...
+        print("Copying parser files")
+        if os.path.exists(dest_path):
+            shutil.rmtree(dest_path)
+        shutil.copytree("swh/search/query_language", dest_path)
 
     print("Getting path")
     path = subprocess.check_output([yarn, "bin"]).decode().strip()
@@ -174,6 +176,7 @@
     cmdclass={
         "build": custom_build,
         "sdist": custom_sdist,
+        "develop": custom_develop,
         "ts_install": TSInstallCommand,
         "ts_build_so": TSBuildSoCommand,
         "ts_build": TSBuildCommand,
diff --git a/swh/search/translator.py b/swh/search/translator.py
--- a/swh/search/translator.py
+++ b/swh/search/translator.py
@@ -1,10 +1,19 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import logging
 import os
+import tempfile
 
 from pkg_resources import resource_filename
 from tree_sitter import Language, Parser
 
 from swh.search.utils import get_expansion, unescape
 
+logger = logging.getLogger(__name__)
+
 
 class Translator:
 
@@ -16,16 +25,13 @@
     }
 
     def __init__(self):
-        ql_rel_paths = [
-            "static/swh_ql.so",  # installed
-            "../../query_language/swh_ql.so",  # development
-        ]
-        for ql_rel_path in ql_rel_paths:
-            ql_path = resource_filename("swh.search", ql_rel_path)
-            if os.path.exists(ql_path):
-                break
-        else:
-            assert False, "swh_ql.so was not found in any of the expected paths"
+        ql_path = resource_filename("swh.search", "static/swh_ql.so")
+        if not os.path.exists(ql_path):
+            logging.info("%s does not exist, building in temporary directory", ql_path)
+            self._build_dir = tempfile.TemporaryDirectory(prefix="swh.search-build")
+            source_path = resource_filename("swh.search", "query_language")
+            ql_path = os.path.join(self._build_dir.name, "swh_ql.so")
+            Language.build_library(ql_path, [source_path])
 
         search_ql = Language(ql_path, "swh_search_ql")