diff --git a/CHANGELOG.md b/CHANGELOG.md
index b27d240..bf298fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,3 +14,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Updated `getAuthorization` to use the correct API URL.
 - Rename `getConnection(name: string)` -> `getAuthorization(developerName: string, attachmentNameOrColorUrl = "HEROKU_APPLINK")`, accepting a new attachmentNameOrColorOrUrl to use a specific Applink addon's config.
 - Remove node-fetch in favor of native fetch, add `HTTPResponseError`
+
+## Unreleased
+- Add `X-App-UUID` header, `heroku-applink-node-sdk` UA.
diff --git a/src/add-ons/heroku-applink.ts b/src/add-ons/heroku-applink.ts
index 1ac91c3..a8277b9 100644
--- a/src/add-ons/heroku-applink.ts
+++ b/src/add-ons/heroku-applink.ts
@@ -47,6 +47,7 @@ export async function getAuthorization(
     method: "GET",
     headers: {
       Authorization: `Bearer ${config.token}`,
+      "X-App-UUID": config.appUuid,
       "Content-Type": "application/json",
     },
     retry: {
diff --git a/src/utils/addon-config.ts b/src/utils/addon-config.ts
index d7e60eb..c5c9783 100644
--- a/src/utils/addon-config.ts
+++ b/src/utils/addon-config.ts
@@ -5,14 +5,23 @@
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
  */
 
+type AppUuid = string;
+
 interface AddonConfig {
   apiUrl: string;
   token: string;
+  appUuid: AppUuid;
 }
 
 export function resolveAddonConfigByAttachmentOrColor(
   attachmentOrColor: string
 ): AddonConfig {
+  const appUuid = process.env.HEROKU_APP_ID;
+
+  if (!appUuid) {
+    throw Error(`Heroku Applink app UUID not found`);
+  }
+
   const addon = process.env.HEROKU_APPLINK_ADDON_NAME || "HEROKU_APPLINK";
 
   let apiUrl;
@@ -37,10 +46,17 @@ export function resolveAddonConfigByAttachmentOrColor(
   return {
     apiUrl,
     token,
+    appUuid,
   };
 }
 
 export function resolveAddonConfigByUrl(url: string): AddonConfig {
+  const appUuid = process.env.HEROKU_APP_ID;
+
+  if (!appUuid) {
+    throw Error(`Heroku Applink app UUID not found`);
+  }
+
   // Find the environment variable ending with _API_URL that matches the given URL
   const envVarEntries = Object.entries(process.env);
   const matchingApiUrlEntry = envVarEntries.find(
@@ -65,5 +81,6 @@ export function resolveAddonConfigByUrl(url: string): AddonConfig {
   return {
     apiUrl: matchingApiUrlEntry[1],
     token,
+    appUuid,
   };
 }
diff --git a/src/utils/request.ts b/src/utils/request.ts
index 9509923..942a060 100644
--- a/src/utils/request.ts
+++ b/src/utils/request.ts
@@ -5,6 +5,9 @@
  * For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
  */
 
+import fs from "fs";
+import path from "path";
+
 /** Error thrown by the SDK when receiving non-2xx responses on HTTP requests. */
 export class HTTPResponseError extends Error {
   response: any;
@@ -19,7 +22,19 @@ export class HTTPResponseError extends Error {
  */
 export class HttpRequestUtil {
   async request(url: string, opts: any, json = true) {
-    const response = await fetch(url, opts);
+    const pjson = fs.readFileSync(
+      path.join(__dirname, "..", "package.json"),
+      "utf8"
+    );
+    const pkg = JSON.parse(pjson);
+
+    const defaultOpts = {
+      headers: {
+        "User-Agent": `heroku-applink-node-sdk/${pkg.version}`,
+      },
+    };
+
+    const response = await fetch(url, { ...defaultOpts, ...opts });
 
     if (!response.ok) {
       throw new HTTPResponseError(response);
diff --git a/test/add-ons/heroku-applink.test.ts b/test/add-ons/heroku-applink.test.ts
index c2f7cb2..729d8fe 100644
--- a/test/add-ons/heroku-applink.test.ts
+++ b/test/add-ons/heroku-applink.test.ts
@@ -45,6 +45,7 @@ describe("getAuthorization", () => {
     process.env.HEROKU_APPLINK_PURPLE_API_URL =
       "https://applink.staging.herokudev.com/addons/536c15d8-c2c1-47f7-a582-76f5aae385e0";
     process.env.HEROKU_APPLINK_PURPLE_TOKEN = "purple-token";
+    process.env.HEROKU_APP_ID = "d52a726b-11a4-47a1-a4b6-2e18a771c2ac";
     httpRequestStub = sinon.stub(HttpRequestUtil.prototype, "request");
   });
 
diff --git a/test/utils/addon-config.test.ts b/test/utils/addon-config.test.ts
index 2cf9dd1..36f26f3 100644
--- a/test/utils/addon-config.test.ts
+++ b/test/utils/addon-config.test.ts
@@ -18,6 +18,7 @@ describe("resolveAddonConfigByAttachmentOrColor", () => {
 
   beforeEach(() => {
     originalEnv = { ...process.env };
+    process.env.HEROKU_APP_ID = "d52a726b-11a4-47a1-a4b6-2e18a771c2ac";
   });
 
   afterEach(() => {
@@ -81,6 +82,14 @@ describe("resolveAddonConfigByAttachmentOrColor", () => {
       "Heroku Applink config not found under attachment or color HEROKU_APPLINK"
     );
   });
+
+  it("throws if HEROKU_APP_ID is not set", () => {
+    delete process.env.HEROKU_APP_ID;
+
+    expect(() => resolveAddonConfigByAttachmentOrColor(ATTACHMENT)).to.throw(
+      "Heroku Applink app UUID not found"
+    );
+  });
 });
 
 describe("resolveAddonConfigByUrl", () => {
@@ -88,6 +97,7 @@ describe("resolveAddonConfigByUrl", () => {
 
   beforeEach(() => {
     originalEnv = { ...process.env };
+    process.env.HEROKU_APP_ID = "d52a726b-11a4-47a1-a4b6-2e18a771c2ac";
   });
 
   afterEach(() => {
@@ -131,4 +141,12 @@ describe("resolveAddonConfigByUrl", () => {
       `Heroku Applink token not found for API URL: ${testUrl}`
     );
   });
+
+  it("throws if HEROKU_APP_ID is not set", () => {
+    delete process.env.HEROKU_APP_ID;
+
+    expect(() => resolveAddonConfigByUrl("https://api.example.com")).to.throw(
+      "Heroku Applink app UUID not found"
+    );
+  });
 });