diff --git a/README.md b/README.md
index ff79986..8843593 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,20 @@ ip -br a | curl -X POST https://aukpad.com --data-binary @-   # command output
 
 ## Installation
 
+### Environment Variables
+
+The following environment variables can be configured:
+
+| Variable | Default | Description |
+|----------|---------|-------------|
+| `USE_VALKEY` | `false` | Enable Valkey/Redis caching. Set to `true` to enable |
+| `VALKEY_URL` | `redis://localhost:6379/0` | Redis/Valkey connection URL |
+| `MAX_TEXT_SIZE` | `1048576` | Maximum text size in bytes (1MB default) |
+| `MAX_CONNECTIONS_PER_IP` | `10` | Maximum concurrent connections per IP address |
+| `RETENTION_HOURS` | `48` | How long to retain pads in hours (48 hours default) |
+
+### Running
+
 WORK IN PROGRESS
 
 ---