diff --git a/docs/nix_dev_env.md b/docs/nix_dev_env.md
--- a/docs/nix_dev_env.md
+++ b/docs/nix_dev_env.md
@@ -11,7 +11,7 @@
 # Supported workflows
 
 | Workflow                      | Supported on macOS |
-| ----------------------------- | ------------------- 
+| ----------------------------- | ------------------ |
 | keyserver (Node.js)           | ❌                 |
 | web (Webpack)                 | ❌                 |
 | native iOS (React Native)     | ❌                 |
@@ -51,6 +51,15 @@
 experimental-features = nix-command flakes
 ```
 
+For use of comm's binary caches, please add yourself as a trusted user. This should reflect what `echo $USER` prints.
+
+```
+trusted-users = <user>
+# alternatively add groups using `@`
+trusted-users = @admin # macOS
+trusted-users = @wheel # linux
+```
+
 # Development Environment
 
 Run `nix develop` to create a dev environment.