diff --git a/.github/vale/styles/Aiven/capitalization_headings.yml b/.github/vale/styles/Aiven/capitalization_headings.yml
index 5dcde3dcfc..c5e89682dd 100644
--- a/.github/vale/styles/Aiven/capitalization_headings.yml
+++ b/.github/vale/styles/Aiven/capitalization_headings.yml
@@ -101,6 +101,7 @@ exceptions:
   - Schema Registry
   - Simple Authentication and Security Layer
   - Skyvia
+  - Slack
   - Snowflake
   - Sphinx
   - Splunk