diff --git a/src/commands/export.test.ts b/src/commands/export.test.ts
new file mode 100644
index 0000000..21d1afa
--- /dev/null
+++ b/src/commands/export.test.ts
@@ -0,0 +1,16 @@
+import { describe, it, expect } from "vitest";
+import { defaultOutputPath } from "./export.js";
+
+describe("defaultOutputPath", () => {
+  it("uses the job id when no output is given", () => {
+    expect(defaultOutputPath("exp_a1b2c3d4e5f6")).toBe("pixelvault-export-exp_a1b2c3d4e5f6.tar");
+  });
+
+  it("honors an explicit output path", () => {
+    expect(defaultOutputPath("exp_x", "./backups/mine.tar")).toBe("./backups/mine.tar");
+  });
+
+  it("falls back to the default for an empty output string", () => {
+    expect(defaultOutputPath("exp_x", "")).toBe("pixelvault-export-exp_x.tar");
+  });
+});
diff --git a/src/commands/export.ts b/src/commands/export.ts
new file mode 100644
index 0000000..fc6556c
--- /dev/null
+++ b/src/commands/export.ts
@@ -0,0 +1,161 @@
+import { defineCommand } from "citty";
+import { writeFileSync, mkdirSync } from "node:fs";
+import { execFileSync } from "node:child_process";
+import { apiRequest } from "../lib/client.js";
+import { getApiUrl, requireApiKey } from "../lib/config.js";
+import { stdout, stderr, jsonOut } from "../lib/output.js";
+import { CliError } from "../lib/errors.js";
+
+interface StartResponse {
+  job_id: string;
+  status: string;
+  image_count: number;
+  status_url: string;
+}
+
+interface StatusResponse {
+  id: string;
+  status: "pending" | "processing" | "complete" | "failed" | "expired";
+  image_count: number;
+  processed_count: number;
+  bytes: number;
+  created_at: string;
+  expires_at: string;
+  download_url?: string;
+  error?: string;
+}
+
+/** Default archive filename when `--output` isn't given. Pure, for tests. */
+export function defaultOutputPath(jobId: string, out?: string): string {
+  return out && out.length > 0 ? out : `pixelvault-export-${jobId}.tar`;
+}
+
+const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
+
+export default defineCommand({
+  meta: {
+    name: "export",
+    description:
+      "Export every image in your project as a tar archive (manifest.json + all images). Your data is always portable — no lock-in.",
+  },
+  args: {
+    output: {
+      type: "string",
+      description: "Write the archive to this path (default: pixelvault-export-<job>.tar)",
+      alias: "o",
+    },
+    extract: {
+      type: "boolean",
+      description: "Extract the archive into a directory after download (requires `tar`)",
+      default: false,
+    },
+    timeout: {
+      type: "string",
+      description: "Max seconds to wait for the export to finish (default: 600)",
+      default: "600",
+    },
+    json: {
+      type: "boolean",
+      description: "Output the final job JSON to stdout",
+      default: false,
+    },
+  },
+  async run({ args }) {
+    const apiKey = requireApiKey();
+    const timeoutMs = (Number(args.timeout) || 600) * 1000;
+
+    // 1. Start the async export job (project-scoped by the secret key).
+    let start: StartResponse;
+    try {
+      start = await apiRequest<StartResponse>({ method: "POST", path: "/v1/export", auth: apiKey });
+    } catch (err) {
+      // Surface the "already running" case helpfully.
+      if (err instanceof CliError && /in progress/i.test(err.message)) {
+        throw new CliError(
+          "An export for this project is already in progress. Wait for it to finish, then try again.",
+          1,
+        );
+      }
+      throw err;
+    }
+    stderr(`Export started — ${start.image_count} image(s), job ${start.job_id}`);
+
+    // 2. Poll until the archive is ready (backoff 1s → 5s).
+    const deadline = Date.now() + timeoutMs;
+    let status: StatusResponse;
+    let delay = 1000;
+    for (;;) {
+      status = await apiRequest<StatusResponse>({
+        path: `/v1/export-jobs/${encodeURIComponent(start.job_id)}`,
+        auth: apiKey,
+      });
+      if (status.status === "complete") break;
+      if (status.status === "failed") {
+        throw new CliError(`Export failed: ${status.error ?? "unknown error"}`, 1);
+      }
+      if (status.status === "expired") {
+        throw new CliError("Export expired before it could be downloaded. Start a new one.", 1);
+      }
+      if (Date.now() > deadline) {
+        throw new CliError(
+          `Timed out after ${args.timeout}s (job still ${status.status}). It may still finish — re-run to poll, or raise --timeout.`,
+          1,
+        );
+      }
+      stderr(`  ${status.status}… ${status.processed_count}/${status.image_count}`);
+      await sleep(delay);
+      delay = Math.min(Math.round(delay * 1.5), 5000);
+    }
+
+    // 3. Download the tar. apiRequest parses JSON, so fetch the raw bytes directly
+    // (the endpoint requires the same Bearer auth).
+    const out = defaultOutputPath(start.job_id, args.output as string | undefined);
+    const downloadUrl = `${getApiUrl()}/v1/export-jobs/${encodeURIComponent(start.job_id)}/download`;
+    let bytes: ArrayBuffer;
+    try {
+      const dl = await fetch(downloadUrl, { headers: { Authorization: `Bearer ${apiKey}` } });
+      if (!dl.ok) throw new CliError(`Failed to download export: HTTP ${dl.status}`, 1);
+      bytes = await dl.arrayBuffer();
+    } catch (err) {
+      if (err instanceof CliError) throw err;
+      throw new CliError(
+        `Failed to download export: ${err instanceof Error ? err.message : String(err)}`,
+        1,
+      );
+    }
+    // A 200 with an empty/truncated body must not report success for a backup.
+    if (bytes.byteLength === 0) {
+      throw new CliError("Downloaded 0 bytes — refusing to write an empty archive.", 1);
+    }
+    try {
+      writeFileSync(out, Buffer.from(bytes));
+    } catch (err) {
+      throw new CliError(
+        `Failed to save ${out}: ${err instanceof Error ? err.message : String(err)}`,
+        1,
+      );
+    }
+    stderr(`Saved ${out} — ${status.image_count} image(s), ${bytes.byteLength} bytes`);
+
+    // 4. Optional extraction via the system `tar`.
+    if (args.extract) {
+      const dir = out.replace(/\.tar$/, "") || `${out}-extracted`;
+      try {
+        mkdirSync(dir, { recursive: true });
+        execFileSync("tar", ["-xf", out, "-C", dir], { stdio: "ignore" });
+        stderr(`Extracted into ${dir}/`);
+      } catch (err) {
+        throw new CliError(
+          `Saved ${out}, but extraction failed (is \`tar\` installed?): ${err instanceof Error ? err.message : String(err)}`,
+          1,
+        );
+      }
+    }
+
+    if (args.json) {
+      jsonOut({ ...status, output: out });
+    } else {
+      stdout(out); // machine-parseable path on stdout; progress went to stderr
+    }
+  },
+});
diff --git a/src/index.ts b/src/index.ts
index 401bbd9..ecd4f7b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -15,6 +15,7 @@ const main = defineCommand({
     list: () => import("./commands/list.js").then((m) => m.default),
     get: () => import("./commands/get.js").then((m) => m.default),
     delete: () => import("./commands/delete.js").then((m) => m.default),
+    export: () => import("./commands/export.js").then((m) => m.default),
     whoami: () => import("./commands/whoami.js").then((m) => m.default),
     config: () => import("./commands/config.js").then((m) => m.default),
   },