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

# Off the Hook: TRON Webhook Notifications

> Off the Hook delivers real-time webhook notifications for TRON blockchain transfers. Get signed HTTPS POSTs for TRX, USDT, USDC, and any TRC-20 token.

Off the Hook gives you real-time, cryptographically signed webhook notifications for every token transfer on TRON — TRX, USDT, USDC, USDD, and any TRC-20 contract. You create a subscription, add the addresses you want to watch, and Off the Hook POSTs a Standard Webhooks-compliant payload to your endpoint within seconds of a transfer hitting the chain.

<CardGroup cols={2}>
  <Card title="Quick Start" icon="rocket" href="/quickstart">
    Create your first subscription and receive a live transfer notification in minutes.
  </Card>

  <Card title="Authentication" icon="key" href="/authentication">
    Learn how to obtain your API key and authenticate every request.
  </Card>

  <Card title="Subscriptions" icon="bell" href="/concepts/subscriptions">
    Understand the subscription resource — destinations, events, and address filters.
  </Card>

  <Card title="API Reference" icon="code" href="/api/subscriptions/create">
    Browse the full REST API with request and response schemas.
  </Card>
</CardGroup>

## How it works

Off the Hook polls TRON Mainnet, Nile, and Shasta every three seconds, decodes every TRX and TRC-20 transfer, and matches them against your subscribed addresses. Matched transfers are signed with HMAC-SHA256 using the Standard Webhooks spec and delivered to your HTTPS endpoint with automatic retries.

<Steps>
  <Step title="Get an API key">
    Contact the Off the Hook team to provision your account and receive an `oth_…` API key.
  </Step>

  <Step title="Create a subscription">
    POST to `/v1/subscriptions` with your destination URL and the event types you want to receive.
  </Step>

  <Step title="Add addresses to watch">
    PATCH `/v1/subscriptions/:id/filters/addresses` to add TRON addresses on any supported chain.
  </Step>

  <Step title="Receive signed webhooks">
    Off the Hook fires a signed HTTPS POST to your endpoint whenever a matching transfer is detected.
  </Step>
</Steps>

## Supported networks

Off the Hook covers all three TRON networks with CAIP-2 identifiers you use in every API call:

| Network      | CAIP-2 ID      | Purpose    |
| ------------ | -------------- | ---------- |
| TRON Mainnet | `tron:mainnet` | Production |
| TRON Nile    | `tron:nile`    | Testnet    |
| TRON Shasta  | `tron:shasta`  | Testnet    |

<CardGroup cols={2}>
  <Card title="Verify Signatures" icon="shield-check" href="/guides/verify-signatures">
    Validate every incoming webhook with the Svix library or your own HMAC implementation.
  </Card>

  <Card title="Event Types" icon="list" href="/reference/event-types">
    See the full list of supported event kinds and their payload shapes.
  </Card>

  <Card title="Manage Addresses" icon="address-book" href="/guides/manage-addresses">
    Add, remove, and replace the addresses your subscriptions watch.
  </Card>

  <Card title="Error Codes" icon="triangle-exclamation" href="/reference/error-codes">
    Understand every error code the API can return and how to handle them.
  </Card>
</CardGroup>