diff --git a/README.md b/README.md
index 40ef0d0..5ee4da9 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@ services:
     image: ghcr.io/daltonbr/wol-server:latest
     network_mode: "host"  # Required for WOL broadcast on Linux
     environment:
+      PORT: "5000"  # Optional, defaults to 5000
       WOL_CONFIG: |
         devices:
           desktop:
@@ -76,6 +77,13 @@ curl http://localhost:5000/status
 
 ## Configuration
 
+### Environment Variables
+
+| Variable | Description | Default |
+| -------- | ----------- | ------- |
+| PORT | HTTP server port | 5000 |
+| WOL_CONFIG | YAML configuration (inline) | - |
+
 ### Option 1: Environment Variable (Docker)
 
 Set `WOL_CONFIG` with YAML content (see docker-compose example above).
diff --git a/docs/DEVELOPMENT.md b/docs/DEVELOPMENT.md
index f493ae8..73462c7 100644
--- a/docs/DEVELOPMENT.md
+++ b/docs/DEVELOPMENT.md
@@ -23,7 +23,13 @@ cp config.example.yaml ~/.config/wol-server/config.yaml
 go run .
 ```
 
-**Server runs on:** `http://localhost:5000`
+**Server runs on:** `http://localhost:5000` (or set `PORT` environment variable)
+
+**Change port:**
+
+```bash
+PORT=8080 go run .
+```
 
 ## Testing
 
@@ -89,9 +95,16 @@ docker build -t wol-server:local .
 **Run locally built image:**
 
 ```bash
+# Default port (5000)
 docker run --rm -p 5000:5000 \
   -e WOL_CONFIG="$(cat ~/.config/wol-server/config.yaml)" \
   wol-server:local
+
+# Custom port
+docker run --rm -p 8080:8080 \
+  -e PORT=8080 \
+  -e WOL_CONFIG="$(cat ~/.config/wol-server/config.yaml)" \
+  wol-server:local
 ```
 
 ## Publishing to GHCR
diff --git a/main.go b/main.go
index 97d8a09..cebb187 100644
--- a/main.go
+++ b/main.go
@@ -5,6 +5,7 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"os"
 	"strconv"
 )
 
@@ -15,10 +16,25 @@ func main() {
 		log.Println("Server will only accept direct parameters (mac/ip/port)")
 	}
 
+	// Get port from environment or use default
+	portStr := os.Getenv("PORT")
+	if portStr == "" {
+		portStr = "5000"
+	}
+
+	// Validate port
+	port, err := strconv.Atoi(portStr)
+	if err != nil {
+		log.Fatalf("Invalid PORT environment variable '%s': must be a number", portStr)
+	}
+	if port < 1 || port > 65535 {
+		log.Fatalf("Invalid PORT value %d: must be between 1 and 65535", port)
+	}
+
 	http.HandleFunc("/wake", handler)
 	http.HandleFunc("/status", statusHandler)
-	fmt.Println("Server is listening on port :5000")
-	log.Fatal(http.ListenAndServe(":5000", nil))
+	fmt.Printf("Server is listening on port :%d\n", port)
+	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), nil))
 }
 
 func handler(w http.ResponseWriter, r *http.Request) {