saveBase64Data

Saves Base64-encoded data to the device as a file with the given filename and MIME type. Use this when you need to hand the user an in-memory binary — a PDF from the server, an image, a CSV export.

Signature

import { saveBase64Data } from '@apps-in-toss/web-framework';

declare function saveBase64Data(params: {
  data: string;
  fileName: string;
  mimeType: string;
}): Promise<void>;

Parameters

Name	Type	Required	Description
params.data	string	✓	The raw Base64-encoded string. Pass the Base64 payload only — no data: URI prefix.
params.fileName	string	✓	The filename to save as, including the extension (e.g. report.pdf, photo.jpg).
params.mimeType	string	✓	The file's MIME type (e.g. application/pdf, image/jpeg, text/csv).

Returns

• Promise<void> — resolves once the save completes.
• In the devtools mock, the browser's file download is triggered instead. The real in-app storage behavior is only visible inside the Toss app on iOS / Android.

Permission

No permission required — the storage namespace is not bound to a PermissionName. For the typical permission flow used by other namespaces, see Guides — Permissions pattern.

Examples

Minimal

import { saveBase64Data } from '@apps-in-toss/web-framework';

// Base64 for 'Hello, World!'
await saveBase64Data({
  data: 'SGVsbG8sIFdvcmxkIQ==',
  fileName: 'hello.txt',
  mimeType: 'text/plain',
});

Realistic — saving a server-issued PDF receipt

import { saveBase64Data } from '@apps-in-toss/web-framework';

async function downloadReceipt(orderId: string) {
  // Fetch a Base64-encoded PDF from the server.
  const response = await fetch(`/api/receipts/${orderId}`, {
    headers: { Accept: 'application/json' },
  });
  const { base64Pdf, fileName } = await response.json() as {
    base64Pdf: string;
    fileName: string;
  };

  await saveBase64Data({
    data: base64Pdf,
    fileName: fileName ?? `receipt-${orderId}.pdf`,
    mimeType: 'application/pdf',
  });
}

Try it live

Open the Storage page in sdk-example and run the saveBase64Data card.

→Open in sdk-example

Related APIs

• Storage.setItem — store a string value at a key.
• Storage.getItem — read a value by key.

Related guides

• Guides — Permissions pattern — permission flow for other namespaces (reference only; storage doesn't require a permission).

External references

• @apps-in-toss/web-framework — SDK package. The actual exports are re-exported from @apps-in-toss/web-bridge.