> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ondb.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Blob Storage

> Upload and retrieve binary files like images, videos, and documents

OnDB supports uploading and retrieving binary files like images, videos, and documents.

## Upload Blob

```typescript TypeScript theme={null}
// Browser upload with File object
const fileInput = document.querySelector('input[type="file"]');
const file = fileInput.files[0];

const uploadResult = await client.uploadBlob(
  {
    collection: 'avatars',
    blob: file,
    metadata: {
      user_address: '0xabc...',
      uploaded_by: 'alice',
      is_primary: true
    }
  },
  // Optional payment callback (if collection requires payment)
  async (quote) => {
    const txHash = await processPayment(quote);
    return { txHash, network: quote.network, sender: walletAddress, chainType: quote.chainType, paymentMethod: 'native' };
  }
);

console.log('Blob ID:', uploadResult.blob_id);

// Wait for upload completion
const task = await client.waitForTaskCompletion(uploadResult.ticket_id);
```

## Retrieve Blob

```typescript TypeScript theme={null}
// Browser: Display image
const blob = await client.retrieveBlob({
  collection: 'avatars',
  blob_id: 'blob_abc123'
});

const imageUrl = URL.createObjectURL(blob);
document.querySelector('img').src = imageUrl;

// Node.js: Save file
const buffer = await client.retrieveBlob({
  collection: 'documents',
  blob_id: 'blob_xyz789'
});
fs.writeFileSync('./downloaded-file.pdf', buffer);
```

## Complete Example: Avatar Upload

```typescript TypeScript theme={null}
async function uploadAvatar(file: File, userAddress: string) {
  // Upload blob with payment callback
  const uploadResult = await client.uploadBlob(
    {
      collection: 'avatars',
      blob: file,
      metadata: {
        user_address: userAddress,
        is_primary: true,
        uploaded_at: new Date().toISOString()
      }
    },
    async (quote) => {
      console.log(`Upload will cost ${quote.totalCost} ${quote.tokenSymbol}`);
      const txHash = await processPayment(quote);
      return { txHash, network: quote.network, sender: userAddress, chainType: quote.chainType, paymentMethod: 'native' };
    }
  );

  // Wait for confirmation
  await client.waitForTaskCompletion(uploadResult.ticket_id);

  return uploadResult.blob_id;
}
```

## Supported File Types

OnDB blob storage supports any binary file type including:

* Images (PNG, JPG, GIF, WebP, SVG)
* Videos (MP4, WebM)
* Documents (PDF, DOCX)
* Audio (MP3, WAV)
* Archives (ZIP, TAR)

## Size Limits

Maximum blob size is 2MB per file. For larger files, consider:

* Compressing images before upload
* Splitting large files into chunks
* Using external storage with OnDB for metadata

## Next Steps

<CardGroup cols={2}>
  <Card title="Batch Operations" icon="layer-group" href="/advanced/batch-operations">
    Bulk data operations
  </Card>

  <Card title="Task Management" icon="list-check" href="/advanced/task-management">
    Async operations tracking
  </Card>
</CardGroup>