diff --git a/src/node/app.ts b/src/node/app.ts
index c1b1006df..aece0432c 100644
--- a/src/node/app.ts
+++ b/src/node/app.ts
@@ -94,7 +94,8 @@ export const ensureAddress = (server: http.Server, protocol: string): URL | stri
   }
 
   if (typeof addr !== "string") {
-    return new URL(`${protocol}://${addr.address}:${addr.port}`)
+    const host = addr.family === "IPv6" ? `[${addr.address}]` : addr.address
+    return new URL(`${protocol}://${host}:${addr.port}`)
   }
 
   // If this is a string then it is a pipe or Unix socket.
diff --git a/test/unit/node/app.test.ts b/test/unit/node/app.test.ts
index 62b2887f6..56c0e70dd 100644
--- a/test/unit/node/app.test.ts
+++ b/test/unit/node/app.test.ts
@@ -152,10 +152,20 @@ describe("ensureAddress", () => {
   it("should throw and error if no address", () => {
     expect(() => ensureAddress(mockServer, "http")).toThrow("Server has no address")
   })
-  it("should return the address if it exists", async () => {
-    mockServer.address = () => "http://localhost:8080/"
+  it("should return the address if it's a string", async () => {
+    mockServer.address = () => "/path/to/unix.sock"
     const address = ensureAddress(mockServer, "http")
-    expect(address.toString()).toBe(`http://localhost:8080/`)
+    expect(address.toString()).toBe(`/path/to/unix.sock`)
+  })
+  it("should construct URL with an IPv4 address", async () => {
+    mockServer.address = () => ({ address: "1.2.3.4", port: 5678, family: "IPv4" })
+    const address = ensureAddress(mockServer, "http")
+    expect(address.toString()).toBe(`http://1.2.3.4:5678/`)
+  })
+  it("should construct URL with an IPv6 address", async () => {
+    mockServer.address = () => ({ address: "a:b:c:d::1234", port: 5678, family: "IPv6" })
+    const address = ensureAddress(mockServer, "http")
+    expect(address.toString()).toBe(`http://[a:b:c:d::1234]:5678/`)
   })
 })