diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index 9aeac0596..79deada86 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -9,6 +9,8 @@ build:
   os: ubuntu-22.04
   tools:
     python: "3.11"
+  apt_packages:
+    - doxygen
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
diff --git a/docs/conf.py b/docs/conf.py
index 71a51307d..ef5713b0b 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -64,7 +64,14 @@
     "treeViewIsBootstrap": True,
     "createTreeView" : True,
     "exhaleExecutesDoxygen": True,
-    "exhaleDoxygenStdin": "INPUT = ../include"
+    "exhaleDoxygenStdin": (
+        "INPUT = ../include\n"
+        "ENABLE_PREPROCESSING = YES\n"
+        "MACRO_EXPANSION = YES\n"
+        "EXPAND_ONLY_PREDEF = YES\n"
+        "PREDEFINED += LIBZIM_API=\n"
+        "PREDEFINED += LIBZIM_WITH_XAPIAN=1\n"
+    )
 }
 
 primary_domain = 'cpp'