diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 268f0417e..0d1adc9d7 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -3204,7 +3204,8 @@ matrix_bot_draupnir_container_labels_traefik_docker_network: "{{ matrix_playbook
 matrix_bot_draupnir_container_labels_web_abuseReporting_traefik_entrypoints: "{{ traefik_entrypoint_primary }}"
 matrix_bot_draupnir_container_labels_web_abuseReporting_traefik_tls_certResolver: "{{ traefik_certResolver_primary }}"
 
-matrix_bot_draupnir_config_web_synapseHTTPAntispam_authorization: "{{ '%s' | format(matrix_homeserver_generic_secret_key) | password_hash('sha512', 'draupnir.synapseHTTPAntispam', rounds=655555) | to_uuid }}" # noqa var-naming
+#The salt is size restricted here as a maximum salt size of 16 characters exists due to the functions used.
+matrix_bot_draupnir_config_web_synapseHTTPAntispam_authorization: "{{ '%s' | format(matrix_homeserver_generic_secret_key) | password_hash('sha512', 'draupnir.httpmod', rounds=655555) | to_uuid }}" # noqa var-naming
 
 ######################################################################
 #
@@ -3256,6 +3257,24 @@ matrix_appservice_draupnir_for_all_database_password: "{{ '%s' | format(matrix_h
 #
 ######################################################################
 
+######################################################################
+#
+# matrix-synapse-ext-synapse-http-antispam
+#
+######################################################################
+
+matrix_synapse_ext_synapse_http_antispam_enabled: "{{ matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled }}"
+matrix_synapse_ext_synapse_http_antispam_config_base_url: "{{ matrix_bot_draupnir_synapse_http_antispam_config_base_url if matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled else '' }}"
+matrix_synapse_ext_synapse_http_antispam_config_authorization: "{{ matrix_bot_draupnir_config_web_synapseHTTPAntispam_authorization if matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled else '' }}"
+matrix_synapse_ext_synapse_http_antispam_config_enabled_callbacks_yaml: "{{ matrix_bot_draunpir_synapse_http_antispam_config_enabled_callbacks_yaml if matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled else '' }}"
+matrix_synapse_ext_synapse_http_antispam_config_fail_open_yaml: "{{ matrix_bot_draupnir_synapse_http_antispam_config_fail_open_yaml if matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled else '' }}"
+matrix_synapse_ext_synapse_http_antispam_config_async_yaml: "{{ matrix_bot_draupnir_synapse_http_antispam_config_async_yaml if matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled else '' }}"
+
+######################################################################
+#
+# /matrix-synapse-ext-synapse-http-antispam
+#
+######################################################################
 
 ######################################################################
 #
diff --git a/roles/custom/matrix-bot-draupnir/defaults/main.yml b/roles/custom/matrix-bot-draupnir/defaults/main.yml
index ea61ed4f8..fa5a5fef2 100644
--- a/roles/custom/matrix-bot-draupnir/defaults/main.yml
+++ b/roles/custom/matrix-bot-draupnir/defaults/main.yml
@@ -138,6 +138,25 @@ matrix_bot_draupnir_web_url: 'http://matrix-bot-draupnir'
 matrix_bot_draupnir_config_web_synapseHTTPAntispam_enabled: false  # noqa var-naming
 matrix_bot_draupnir_config_web_synapseHTTPAntispam_authorization: ''  # noqa var-naming
 
+# This controls the URL that the module targets in Draupnir.
+matrix_bot_draupnir_synapse_http_antispam_config_base_url: "{{ matrix_bot_draupnir_web_url }}:{{ matrix_bot_draupnir_config_web_port }}/api/1/spam_check"
+
+# These variables control the configuration of the Synapse module as the configuration is highly consumer dependent.
+# Therefore the module is configured from Draupnir because the consumer of the module determines what settings are relevant.
+
+matrix_bot_draunpir_synapse_http_antispam_config_enabled_callbacks_yaml: |
+  - check_event_for_spam
+  - user_may_invite
+  - user_may_join_room
+
+matrix_bot_draupnir_synapse_http_antispam_config_fail_open_yaml: |
+  check_event_for_spam: true
+  user_may_invite: true
+  user_may_join_room: true
+
+matrix_bot_draupnir_synapse_http_antispam_config_async_yaml: |
+  check_event_for_spam: true
+
 # Default configuration template which covers the generic use case.
 # You can customize it by controlling the various variables inside it.
 #
diff --git a/roles/custom/matrix-synapse/defaults/main.yml b/roles/custom/matrix-synapse/defaults/main.yml
index 8250c0c64..a611e862d 100644
--- a/roles/custom/matrix-synapse/defaults/main.yml
+++ b/roles/custom/matrix-synapse/defaults/main.yml
@@ -1409,6 +1409,38 @@ matrix_synapse_ext_spam_checker_mjolnir_antispam_config:
   ban_lists: "{{ matrix_synapse_ext_spam_checker_mjolnir_antispam_config_ban_lists }}"
   message_max_length: "{{ matrix_synapse_ext_spam_checker_mjolnir_antispam_config_message_max_length }}"
 
+# Enable this to activate the synapse-http-antispam module.
+# See: github.com/maunium/synapse-http-antispam
+matrix_synapse_ext_synapse_http_antispam_enabled: false
+matrix_synapse_ext_synapse_http_antispam_git_repository_url: "https://github.com/maunium/synapse-http-antispam"
+# renovate: datasource=github-releases depName=maunium/synapse-http-antispam
+matrix_synapse_ext_synapse_http_antispam_git_version: "v0.3.0"
+# Where Synapse can locate the consumer of the antispam API. Currently
+# Draupnir is the only consumer of this API that is playbook supported.
+# But https://github.com/maunium/meowlnir also supports the API.
+matrix_synapse_ext_synapse_http_antispam_config_base_url: ''
+# This is a shared secret that is established between the consumer and the
+# homeserver a lot like how AS authentication is done. This is fully managed
+# the same way AS authentication is by the playbook.
+matrix_synapse_ext_synapse_http_antispam_config_authorization: ''
+# This controls what callbacks are activated. This list is fully dependent on what consumer is in play.
+# And what capabilities said consumer should or shouldn't have. There are also performance implications
+# to these choices.
+matrix_synapse_ext_synapse_http_antispam_config_enabled_callbacks: ''
+# Controls if a loss of connectivity to the consumer results in fail open or closed.
+# As in if failure results in events getting flagged automatically as spam or not.
+matrix_synapse_ext_synapse_http_antispam_config_fail_open: ''
+# Controls if the checking is blocking or not. This allows the homeserver to skip waiting for a consumer response.
+matrix_synapse_ext_synapse_http_antispam_config_async: ''
+# Actual configuration passed to the synapse-http-antispam module
+matrix_synapse_ext_synapse_http_antispam_config: "{{ matrix_synapse_ext_synapse_http_antispam_config_yaml | from_yaml }}"
+matrix_synapse_ext_synapse_http_antispam_config_yaml: |
+  base_url: {{ matrix_synapse_ext_synapse_http_antispam_config_base_url | to_json }}
+  authorization: {{ matrix_synapse_ext_synapse_http_antispam_config_authorization | to_json }}
+  enabled_callbacks: {{ matrix_synapse_ext_synapse_http_antispam_config_enabled_callbacks_yaml | from_yaml }}
+  fail_open: {{ matrix_synapse_ext_synapse_http_antispam_config_fail_open_yaml | from_yaml }}
+  async: {{ matrix_synapse_ext_synapse_http_antispam_config_async_yaml | from_yaml }}
+
 # Enable this to activate the E2EE disabling Synapse module.
 # See: https://github.com/digitalentity/matrix_encryption_disabler
 matrix_synapse_ext_encryption_disabler_enabled: false
diff --git a/roles/custom/matrix-synapse/tasks/ext/setup_install.yml b/roles/custom/matrix-synapse/tasks/ext/setup_install.yml
index 17bd5670b..b5f9c6227 100644
--- a/roles/custom/matrix-synapse/tasks/ext/setup_install.yml
+++ b/roles/custom/matrix-synapse/tasks/ext/setup_install.yml
@@ -66,6 +66,19 @@
     - when: matrix_synapse_ext_spam_checker_mjolnir_antispam_enabled | bool
       ansible.builtin.include_tasks: "{{ role_path }}/tasks/ext/mjolnir-antispam/setup_install.yml"
 
+# synapse-http-antispam
+- tags:
+    - setup-all
+    - setup-synapse
+    - install-all
+    - install-synapse
+  block:
+    - when: matrix_synapse_ext_synapse_http_antispam_enabled  | bool
+      ansible.builtin.include_tasks: "{{ role_path }}/tasks/ext/synapse-http-antispam/validate_config.yml"
+
+    - when: matrix_synapse_ext_synapse_http_antispam_enabled | bool
+      ansible.builtin.include_tasks: "{{ role_path }}/tasks/ext/synapse-http-antispam/setup_install.yml"
+
 # s3-storage-provider
 - tags:
     - setup-all
diff --git a/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/setup_install.yml b/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/setup_install.yml
new file mode 100644
index 000000000..aecb68e4e
--- /dev/null
+++ b/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/setup_install.yml
@@ -0,0 +1,37 @@
+# SPDX-FileCopyrightText: 2025 MDAD project contributors
+# SPDX-FileCopyrightText: 2025 Catalan Lover <catalanlover@protonmail.com>
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+---
+
+- name: Ensure git installed
+  ansible.builtin.package:
+    name: git
+    state: present
+
+- name: Clone synapse-http-antispam git repository
+  ansible.builtin.git:
+    repo: "{{ matrix_synapse_ext_synapse_http_antispam_git_repository_url }}"
+    version: "{{ matrix_synapse_ext_synapse_http_antispam_git_version }}"
+    dest: "{{ matrix_synapse_ext_path }}/synapse-http-antispam"
+  become: true
+  become_user: "{{ matrix_synapse_username }}"
+
+- ansible.builtin.set_fact:
+    matrix_synapse_modules: >
+      {{
+        matrix_synapse_modules | default([])
+        +
+        [{
+          "module": "synapse_http_antispam.HTTPAntispam",
+          "config": matrix_synapse_ext_synapse_http_antispam_config,
+        }]
+      }}
+
+    matrix_synapse_container_extra_arguments: >
+      {{
+        matrix_synapse_container_extra_arguments | default([])
+        +
+        ["--mount type=bind,src={{ matrix_synapse_ext_path }}/synapse-http-antispam/synapse_http_antispam.py,dst={{ matrix_synapse_in_container_python_packages_path }}/synapse_http_antispam.py,ro"]
+      }}
diff --git a/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/setup_uninstall.yml b/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/setup_uninstall.yml
new file mode 100644
index 000000000..1b7985f57
--- /dev/null
+++ b/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/setup_uninstall.yml
@@ -0,0 +1,11 @@
+# SPDX-FileCopyrightText: 2025 MDAD project contributors
+# SPDX-FileCopyrightText: 2025 Catalan Lover <catalanlover@protonmail.com>
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+---
+
+- name: Ensure synapse-http-antispam doesn't exist
+  ansible.builtin.file:
+    path: "{{ matrix_synapse_ext_path }}/synapse-http-antispam"
+    state: absent
diff --git a/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/validate_config.yml b/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/validate_config.yml
new file mode 100644
index 000000000..037842f14
--- /dev/null
+++ b/roles/custom/matrix-synapse/tasks/ext/synapse-http-antispam/validate_config.yml
@@ -0,0 +1,21 @@
+# SPDX-FileCopyrightText: 2025 MDAD project contributors
+# SPDX-FileCopyrightText: 2025 Catalan Lover <catalanlover@protonmail.com>
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+---
+- name: Fail if required synapse-http-antispam settings not defined
+  ansible.builtin.fail:
+    msg: >-
+      You need to define a required configuration setting (`{{ item }}`) for using synapse-http-antispam.
+  when: "vars[item] == ''"
+  with_items:
+    - "matrix_synapse_ext_synapse_http_antispam_enabled"
+    - "matrix_synapse_ext_synapse_http_antispam_config_base_url"
+    - "matrix_synapse_ext_synapse_http_antispam_config_authorization"
+
+- name: Fail if required matrix_synapse_ext_synapse_http_antispam_config_base_url looks invalid
+  ansible.builtin.fail:
+    msg: >-
+      `matrix_synapse_ext_synapse_http_antispam_config_base_url` needs to look like a URL (`http://` or `https://` prefix).
+  when: "not matrix_synapse_ext_synapse_http_antispam_config_base_url.startswith('http')"