diff --git a/README.md b/README.md
index 4da8779..632519b 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,38 @@ upstash team add-member --team-id $TEAM_ID --member-email you@example.com --role
 
 Run `upstash --help` (or `--help` on any subcommand) to discover everything else, and check the [full docs](https://upstash.com/docs/agent-resources/cli) for the complete catalog.
 
+## Telemetry
+
+The CLI identifies itself to the Upstash API on each request, so we can see which
+clients our endpoints are serving. It sends three headers and nothing else:
+
+| Header | Example |
+| --- | --- |
+| `Upstash-Telemetry-Sdk` | `@upstash/cli@1.2.0` |
+| `Upstash-Telemetry-Runtime` | `node@22.14.0` |
+| `Upstash-Telemetry-Platform` | `darwin` |
+
+That is the CLI version, the JS runtime, and the OS platform. No command
+arguments, credentials, resource names, or file paths are collected.
+
+To turn it off:
+
+```bash
+upstash telemetry disable   # saved to your config file
+upstash telemetry status    # check the current setting
+upstash telemetry enable    # turn it back on
+```
+
+Or set the environment variable every Upstash SDK honors, which also works from
+a `.env` file and takes precedence over the saved setting:
+
+```bash
+export UPSTASH_DISABLE_TELEMETRY=1
+```
+
+Disabling telemetry never affects what the CLI can do. `upstash logout` keeps
+the setting, so signing out does not quietly turn it back on.
+
 ## Contributing
 
 ```bash
diff --git a/src/cli.ts b/src/cli.ts
index 0358e86..e6a8a1b 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -10,6 +10,7 @@ import { registerQStash } from "./commands/qstash/index.js";
 import { registerLogin } from "./commands/login.js";
 import { registerLogout } from "./commands/logout.js";
 import { registerStartRedis } from "./commands/start-redis.js";
+import { registerTelemetry } from "./commands/telemetry.js";
 import { handleError } from "./output.js";
 import dotenv from "dotenv";
 
@@ -41,6 +42,7 @@ program
 registerLogin(program);
 registerLogout(program);
 registerStartRedis(program);
+registerTelemetry(program);
 registerRedis(program);
 registerTeam(program);
 registerVector(program);
diff --git a/src/client.ts b/src/client.ts
index f8f1af2..5f10354 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -1,4 +1,5 @@
 import type { Auth } from "./auth.js";
+import { telemetryHeaders } from "./telemetry.js";
 
 const BASE_URL = "https://api.upstash.com";
 
@@ -22,6 +23,7 @@ export async function request<T>(
     headers: {
       Authorization: `Basic ${credentials}`,
       "Content-Type": "application/json",
+      ...telemetryHeaders(),
     },
     body: body !== undefined ? JSON.stringify(body) : undefined,
   });
diff --git a/src/commands/telemetry.ts b/src/commands/telemetry.ts
new file mode 100644
index 0000000..5fc59e7
--- /dev/null
+++ b/src/commands/telemetry.ts
@@ -0,0 +1,38 @@
+import { Command } from "commander";
+import { writeTelemetryDisabled } from "../config.js";
+import { telemetryStatus } from "../telemetry.js";
+import { printJSON } from "../output.js";
+
+export function registerTelemetry(program: Command): void {
+  const telemetry = program
+    .command("telemetry")
+    .description(
+      "Show or change whether the CLI identifies itself to Upstash. It sends the CLI version, the JS runtime, and the OS platform — never command arguments, credentials, or resource names.",
+    );
+
+  telemetry
+    .command("status")
+    .description("Report whether telemetry is enabled, and what turned it off")
+    .action(() => {
+      printJSON(telemetryStatus());
+    });
+
+  telemetry
+    .command("disable")
+    .description("Stop sending telemetry headers, saved to the user config file")
+    .action(() => {
+      const path = writeTelemetryDisabled(true);
+      console.log(`Telemetry disabled, saved to ${path}`);
+    });
+
+  telemetry
+    .command("enable")
+    .description("Resume sending telemetry headers, saved to the user config file")
+    .action(() => {
+      const path = writeTelemetryDisabled(false);
+      console.log(`Telemetry enabled, saved to ${path}`);
+      if (!telemetryStatus().enabled) {
+        console.log("Still disabled by UPSTASH_DISABLE_TELEMETRY: unset it to take effect.");
+      }
+    });
+}
diff --git a/src/config.ts b/src/config.ts
index 077f66f..efe3001 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -6,8 +6,11 @@ import type { Auth } from "./auth.js";
 interface StoredConfig {
   email?: string;
   api_key?: string;
+  telemetry_disabled?: boolean;
 }
 
+type RawConfig = StoredConfig & { apiKey?: string };
+
 export function getConfigDir(): string {
   const override = process.env.UPSTASH_CONFIG_HOME;
   if (override) return override;
@@ -29,7 +32,7 @@ export function getLegacyConfigPath(): string {
   return join(base, ".upstash.json");
 }
 
-function readConfigFile(path: string): Auth | null {
+function readRawConfig(path: string): RawConfig | null {
   if (!existsSync(path)) return null;
   let raw: string;
   try {
@@ -37,12 +40,16 @@ function readConfigFile(path: string): Auth | null {
   } catch {
     return null;
   }
-  let parsed: StoredConfig & { apiKey?: string };
   try {
-    parsed = JSON.parse(raw) as StoredConfig & { apiKey?: string };
+    return JSON.parse(raw) as RawConfig;
   } catch {
     return null;
   }
+}
+
+function readConfigFile(path: string): Auth | null {
+  const parsed = readRawConfig(path);
+  if (!parsed) return null;
   // Accept the new snake_case `api_key` or the legacy camelCase `apiKey`.
   const apiKey = parsed.api_key ?? parsed.apiKey;
   if (!parsed.email || !apiKey) return null;
@@ -53,17 +60,52 @@ export function readConfig(): Auth | null {
   return readConfigFile(getConfigPath()) ?? readConfigFile(getLegacyConfigPath());
 }
 
-export function writeConfig(auth: Auth): string {
+function writeStoredConfig(body: StoredConfig): string {
   const path = getConfigPath();
   mkdirSync(dirname(path), { recursive: true, mode: 0o700 });
-  const body: StoredConfig = { email: auth.email, api_key: auth.apiKey };
   writeFileSync(path, JSON.stringify(body, null, 2) + "\n", { mode: 0o600 });
   return path;
 }
 
+export function writeConfig(auth: Auth): string {
+  const existing = readRawConfig(getConfigPath());
+  return writeStoredConfig({
+    email: auth.email,
+    api_key: auth.apiKey,
+    ...(existing?.telemetry_disabled === undefined
+      ? {}
+      : { telemetry_disabled: existing.telemetry_disabled }),
+  });
+}
+
+export function readTelemetryDisabled(): boolean {
+  return readRawConfig(getConfigPath())?.telemetry_disabled === true;
+}
+
+export function writeTelemetryDisabled(disabled: boolean): string {
+  const existing = readRawConfig(getConfigPath());
+  return writeStoredConfig({
+    ...(existing?.email === undefined ? {} : { email: existing.email }),
+    ...(existing?.api_key ?? existing?.apiKey
+      ? { api_key: existing.api_key ?? existing.apiKey }
+      : {}),
+    telemetry_disabled: disabled,
+  });
+}
+
+/**
+ * Drops the credentials, keeping any telemetry preference: logging out must not
+ * silently turn telemetry back on. Returns whether credentials were there.
+ */
 export function deleteConfig(): boolean {
   const path = getConfigPath();
-  if (!existsSync(path)) return false;
-  rmSync(path);
-  return true;
+  const existing = readRawConfig(path);
+  if (!existing) return false;
+  const hadCredentials = Boolean(existing.email && (existing.api_key ?? existing.apiKey));
+  if (existing.telemetry_disabled === undefined) {
+    rmSync(path);
+  } else {
+    writeStoredConfig({ telemetry_disabled: existing.telemetry_disabled });
+  }
+  return hadCredentials;
 }
diff --git a/src/telemetry.ts b/src/telemetry.ts
new file mode 100644
index 0000000..7be1674
--- /dev/null
+++ b/src/telemetry.ts
@@ -0,0 +1,38 @@
+import pkg from "../package.json" with { type: "json" };
+import { getConfigPath, readTelemetryDisabled } from "./config.js";
+
+function runtime(): string {
+  if (process.versions.bun) return `bun@${process.versions.bun}`;
+  if (process.versions.deno) return `deno@${process.versions.deno}`;
+  return `node@${process.versions.node}`;
+}
+
+function isSet(value: string | undefined): boolean {
+  return value !== undefined && value !== "" && value !== "0" && value !== "false";
+}
+
+/**
+ * `UPSTASH_DISABLE_TELEMETRY` is the variable the Upstash SDKs already read. It
+ * wins over the saved preference so a CI job can opt out without writing config.
+ */
+export function telemetryStatus(): { enabled: boolean; disabled_by?: string } {
+  if (isSet(process.env.UPSTASH_DISABLE_TELEMETRY)) {
+    return { enabled: false, disabled_by: "UPSTASH_DISABLE_TELEMETRY" };
+  }
+  if (readTelemetryDisabled()) return { enabled: false, disabled_by: getConfigPath() };
+  return { enabled: true };
+}
+
+/**
+ * Resolved per request rather than at import: `cli.ts` loads the .env file
+ * after the module graph is already evaluated, so an env var read at import
+ * time would miss it.
+ */
+export function telemetryHeaders(): Record<string, string> {
+  if (!telemetryStatus().enabled) return {};
+  return {
+    "Upstash-Telemetry-Sdk": `@upstash/cli@${pkg.version}`,
+    "Upstash-Telemetry-Runtime": runtime(),
+    "Upstash-Telemetry-Platform": process.platform,
+  };
+}
diff --git a/tests/unit/client.test.ts b/tests/unit/client.test.ts
new file mode 100644
index 0000000..c99367d
--- /dev/null
+++ b/tests/unit/client.test.ts
@@ -0,0 +1,26 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { request } from "../../src/client.js";
+
+const auth = { email: "user@example.com", apiKey: "key" };
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
+describe("request", () => {
+  it("identifies the cli through the telemetry headers", async () => {
+    const fetchMock = vi
+      .spyOn(globalThis, "fetch")
+      .mockResolvedValue(new Response("{}", { status: 200 }));
+
+    await request(auth, "GET", "/v2/redis/databases");
+
+    const headers = fetchMock.mock.calls[0]![1]!.headers as Record<string, string>;
+    expect(headers["Upstash-Telemetry-Sdk"]).toMatch(/^@upstash\/cli@/);
+    expect(headers["Upstash-Telemetry-Runtime"]).toBeTruthy();
+    expect(headers["Upstash-Telemetry-Platform"]).toBeTruthy();
+    expect(headers.Authorization).toBe(
+      `Basic ${Buffer.from("user@example.com:key").toString("base64")}`,
+    );
+  });
+});
diff --git a/tests/unit/telemetry.test.ts b/tests/unit/telemetry.test.ts
new file mode 100644
index 0000000..a449f0d
--- /dev/null
+++ b/tests/unit/telemetry.test.ts
@@ -0,0 +1,122 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { mkdtempSync, rmSync, readFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { Command } from "commander";
+import { readConfig, writeConfig, deleteConfig, getConfigPath } from "../../src/config.js";
+import { telemetryHeaders, telemetryStatus } from "../../src/telemetry.js";
+import { request } from "../../src/client.js";
+import { registerTelemetry } from "../../src/commands/telemetry.js";
+
+const auth = { email: "user@example.com", apiKey: "key" };
+
+let dir: string;
+const originalEnv = { ...process.env };
+
+beforeEach(() => {
+  dir = mkdtempSync(join(tmpdir(), "upstash-cli-telemetry-"));
+  process.env.UPSTASH_CONFIG_HOME = dir;
+  process.env.UPSTASH_LEGACY_CONFIG_HOME = dir;
+  delete process.env.UPSTASH_DISABLE_TELEMETRY;
+});
+
+afterEach(() => {
+  rmSync(dir, { recursive: true, force: true });
+  process.env = { ...originalEnv };
+  vi.restoreAllMocks();
+});
+
+async function run(argv: string[]): Promise<string[]> {
+  const output: string[] = [];
+  const origLog = console.log;
+  console.log = (...args: unknown[]) => output.push(args.join(" "));
+  try {
+    const program = new Command().exitOverride();
+    registerTelemetry(program);
+    await program.parseAsync(["node", "upstash", ...argv]);
+  } finally {
+    console.log = origLog;
+  }
+  return output;
+}
+
+describe("telemetryStatus", () => {
+  it("is enabled by default", () => {
+    expect(telemetryStatus()).toEqual({ enabled: true });
+    expect(telemetryHeaders()["Upstash-Telemetry-Sdk"]).toMatch(/^@upstash\/cli@/);
+  });
+
+  it("is disabled by UPSTASH_DISABLE_TELEMETRY", () => {
+    process.env.UPSTASH_DISABLE_TELEMETRY = "1";
+    expect(telemetryStatus()).toEqual({
+      enabled: false,
+      disabled_by: "UPSTASH_DISABLE_TELEMETRY",
+    });
+    expect(telemetryHeaders()).toEqual({});
+  });
+
+  it.each(["", "0", "false"])("ignores a %s env value", (value) => {
+    process.env.UPSTASH_DISABLE_TELEMETRY = value;
+    expect(telemetryStatus().enabled).toBe(true);
+  });
+
+  it("is disabled by the saved preference", async () => {
+    await run(["telemetry", "disable"]);
+    expect(telemetryStatus()).toEqual({ enabled: false, disabled_by: getConfigPath() });
+    expect(telemetryHeaders()).toEqual({});
+  });
+
+  it("sends no telemetry headers on a request when disabled", async () => {
+    await run(["telemetry", "disable"]);
+    const fetchMock = vi
+      .spyOn(globalThis, "fetch")
+      .mockResolvedValue(new Response("{}", { status: 200 }));
+
+    await request(auth, "GET", "/v2/redis/databases");
+
+    const headers = fetchMock.mock.calls[0]![1]!.headers as Record<string, string>;
+    expect(Object.keys(headers).some((key) => key.startsWith("Upstash-Telemetry"))).toBe(false);
+    expect(headers.Authorization).toBeTruthy();
+  });
+
+  it("re-enables through the command", async () => {
+    await run(["telemetry", "disable"]);
+    await run(["telemetry", "enable"]);
+    expect(telemetryStatus().enabled).toBe(true);
+  });
+
+  it("reports an env override as still disabled after enable", async () => {
+    process.env.UPSTASH_DISABLE_TELEMETRY = "1";
+    const output = await run(["telemetry", "enable"]);
+    expect(output.join(" ")).toContain("Still disabled by UPSTASH_DISABLE_TELEMETRY");
+  });
+});
+
+describe("the telemetry preference and credentials are independent", () => {
+  it("survives login", async () => {
+    await run(["telemetry", "disable"]);
+    writeConfig(auth);
+    expect(readConfig()).toEqual(auth);
+    expect(telemetryStatus().enabled).toBe(false);
+  });
+
+  it("survives logout", async () => {
+    writeConfig(auth);
+    await run(["telemetry", "disable"]);
+    expect(deleteConfig()).toBe(true);
+    expect(readConfig()).toBeNull();
+    expect(telemetryStatus().enabled).toBe(false);
+  });
+
+  it("does not report a logout when only the preference was stored", async () => {
+    await run(["telemetry", "disable"]);
+    expect(deleteConfig()).toBe(false);
+  });
+
+  it("keeps the config file readable only by the owner", async () => {
+    await run(["telemetry", "disable"]);
+    expect(JSON.parse(readFileSync(getConfigPath(), "utf8"))).toEqual({
+      telemetry_disabled: true,
+    });
+  });
+});