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

# NFC Writer

> Write node URLs to NFC tags directly from your phone or desktop.

The NFC Writer module lets you encode node URLs directly onto NTAG213/215/216 chips from the NearNode console — no third-party apps required.

## Supported Methods

<CardGroup cols={2}>
  <Card title="Web NFC (Mobile)" icon="mobile">
    Use your Android phone's built-in NFC to write tags. Works in Chrome and as an installed PWA.
  </Card>

  <Card title="Desktop Reader" icon="usb">
    Connect an ACR1252U USB reader for batch writing workflows. *Coming soon.*
  </Card>
</CardGroup>

## Web NFC Quick Start

<Steps>
  <Step title="Open the Writer">
    Navigate to **Writer** in the NearNode dashboard on your Android phone (Chrome or installed PWA).
  </Step>

  <Step title="Select a Node">
    Choose the node you want to write. The URL `nearnode.io/v/{slug}` will be encoded as an NDEF URL record.
  </Step>

  <Step title="Tap to Write">
    Hold the NFC tag to the back of your phone. The writer will encode the URL and optionally verify the write.
  </Step>

  <Step title="Lock (Optional)">
    Enable "Lock after write" to make the tag permanently read-only. **This is irreversible.**
  </Step>
</Steps>

<Warning>
  Locking a tag is **permanent and irreversible**. The chip can never be re-written after locking. Only lock tags when you're certain the correct URL has been written.
</Warning>

## Offline Support

The NearNode PWA supports offline writes. When you're offline:

1. Tags are written normally via Web NFC
2. Write logs are queued in IndexedDB
3. Logs sync automatically when you're back online

<Tip>
  Install NearNode as a PWA for the best writing experience — standalone mode, no browser chrome, and offline queue support.
</Tip>

## Write Log

Every write creates an immutable audit record with:

| Field           | Description                                             |
| --------------- | ------------------------------------------------------- |
| `hardware_uid`  | The chip's serial number (e.g., `04:A2:C8:1A:35:39:80`) |
| `written_url`   | The exact URL written to the tag                        |
| `locked`        | Whether the tag was locked after writing                |
| `verified`      | Whether a read-back verification was performed          |
| `writer_method` | `web_nfc`, `desktop_reader`, or `manual`                |

Write logs cannot be edited or deleted — they serve as a tamper-proof audit trail.

## Browser Support

| Browser                | Web NFC Support |
| ---------------------- | --------------- |
| Chrome (Android)       | Yes             |
| Chrome (iOS)           | No              |
| Safari                 | No              |
| Firefox                | No              |
| NearNode PWA (Android) | Yes             |