> ## Documentation Index
> Fetch the complete documentation index at: https://shinydapps-bd9fa40b.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# DNS Discovery

> Let agents discover your L402 endpoint via DNS TXT record — no HTTP request needed.

## Why DNS discovery

Agents with internet access can resolve DNS before making any HTTP request. If you publish your L402 endpoint as a DNS TXT record, agents discover it automatically — even before hitting your API.

## TXT record format

```
l402._payment.yourdomain.com  TXT  "v=l402 endpoint=https://api.yourdomain.com/data price=10sat docs=https://yourdomain.com/docs"
```

Fields:

* `v=l402` — protocol identifier
* `endpoint=` — your L402-protected URL
* `price=` — price in sats (optional, informational)
* `docs=` — link to your docs (optional)

## Setup on Cloudflare

1. Go to **Cloudflare Dashboard → DNS**
2. Add a new record:

| Type | Name            | Content                                                                                        | TTL  |
| ---- | --------------- | ---------------------------------------------------------------------------------------------- | ---- |
| TXT  | `l402._payment` | `v=l402 endpoint=https://api.yourdomain.com/data price=10sat docs=https://yourdomain.com/docs` | Auto |

## Verify with dig

```bash theme={null}
dig TXT l402._payment.yourdomain.com

# Expected output:
# l402._payment.yourdomain.com. 300 IN TXT "v=l402 endpoint=https://api.yourdomain.com/data price=10sat docs=..."
```

## How agents use it

```typescript theme={null}
import { discoverL402Endpoint } from "l402-kit/agent";

// Agent resolves DNS to find your endpoint
const endpoint = await discoverL402Endpoint("yourdomain.com");
// Returns: "https://api.yourdomain.com/data"

const result = await client.fetch(endpoint);
```

## l402-kit's own record

The example below uses a fictional domain (`api.example.com`) to illustrate the format — replace it with your real endpoint.

```bash theme={null}
dig TXT l402._payment.l402kit.com
# v=l402 endpoint=https://api.example.com/api/demo price=1sat docs=https://docs.l402kit.com
```

## Benefits

* **Zero HTTP overhead** — discovery before any API call
* **Agent-native** — DNS is how machines find services, not humans
* **No API key needed** — completely open discovery
* **Cacheable** — TTL controls how often agents re-resolve

See [.well-known/agent.json](https://api.example.com/.well-known/agent.json) for the complementary HTTP discovery standard.