> ## Documentation Index
> Fetch the complete documentation index at: https://402.cat/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# API Overview

> Getting started with the 402.cat API

## Base URLs

| Environment    | URL                     | Network                     |
| -------------- | ----------------------- | --------------------------- |
| **Production** | `https://agent.402.cat` | Base (eip155:8453)          |
| **Testnet**    | `https://agent.402.cat` | Base Sepolia (eip155:84532) |

Network is auto-detected from your wallet's transaction history.

## Quick Start

```bash theme={null}
# Free endpoint - no payment required
curl https://agent.402.cat/health

# Paid endpoint - requires x402 payment
curl -H "PAYMENT-SIGNATURE: <sig>" \
  https://agent.402.cat/entrypoints/token_info/invoke
```

## Authentication

402.cat uses **x402 micropayment protocol** for authentication. No API keys required.

### Payment Flow

1. Request protected endpoint → Receive `402 Payment Required`
2. Sign EIP-3009 authorization with your wallet
3. Retry request with `PAYMENT-SIGNATURE` header
4. Payment verified → Response returned

See [Authentication](/docs/api-reference/authentication) for details.

## Endpoint Types

### Free Endpoints

No payment required:

* `GET /health` - Health check
* `GET /tokens` - List all tokens
* `GET /tokens/:id` - Token info
* `GET /positions` - User positions
* `GET /api/*` - Read-only data

### Paid Endpoints

Require x402 micropayment:

* `POST /tokens` - Create token (\$0.01)
* `POST /entrypoints/token_buy_*` - Buy tokens (variable)
* `POST /entrypoints/token_sell` - Sell tokens (\$0.01)
* `POST /entrypoints/*` - Various operations

## Response Format

All endpoints return JSON:

```json theme={null}
{
  "success": true,
  "operation": "buy_token",
  "data": {
    "tokenId": "...",
    "tokensReceived": "1234.567"
  }
}
```

**Error format:**

```json theme={null}
{
  "success": false,
  "error": {
    "code": "INSUFFICIENT_FUNDS",
    "message": "Not enough USDC",
    "details": {...}
  }
}
```

## Rate Limits

* **Free endpoints**: 100 req/min per IP
* **Paid endpoints**: No rate limit (pay per use)
* **Quote providers**: Internal rate limiting per provider

## Next Steps

<CardGroup cols={2}>
  <Card title="Authentication" icon="key" href="/docs/api-reference/authentication">
    Learn x402 payment protocol
  </Card>

  <Card title="Token Operations" icon="coins" href="/docs/api-reference/tokens/create">
    Create and trade tokens
  </Card>

  <Card title="Examples" icon="code" href="/docs/api-reference/examples/workflows">
    See complete workflows
  </Card>

  <Card title="Schemas" icon="database" href="/docs/api-reference/schemas/common">
    Common data structures
  </Card>
</CardGroup>