---
name: amnt
description: List an HTTPS API or MCP tool as a paid tool on AMNT (amnt.io) so AI agents can find and pay for it in USDC, check its listing, or use AMNT's free x402 facilitator. Use when the user asks to sell, monetise, publish or list an API or tool, or to accept x402 payments.
---

# AMNT: list an API as a paid tool

Turn any HTTPS endpoint or MCP server into a paid tool that AI agents can find and pay for.
Buyers pay USDC on Base, Solana or Hedera, and 100% goes to the owner's wallet.
The tool is listed in the x402 Bazaar after one paid run, which AMNT makes. No mint, no gas.

## Before you start (ask your human for these)

1. **An AMNT API key.** https://amnt.io/settings?tab=api-keys → Create key. It starts with `amnt_sk_`.
2. **Payout wallets.** https://amnt.io/studio/earnings
   - Base: set up automatically at sign-in.
   - Solana: an address that has held USDC at least once.
   - Hedera: an account id (0.0.x) with the USDC token added.

## Register a tool

```bash
curl -X POST https://amnt.io/api/v1/tools \
  -H "Authorization: Bearer $AMNT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "ETH gas price",
    "description": "Returns the current Ethereum gas price in gwei.",
    "endpoint": { "url": "https://api.example.com/gas/{{input}}", "method": "GET" },
    "api_key": "optional-upstream-key",
    "example_input": "ethereum",
    "price_usd": 0.01,
    "chains": ["base", "solana", "hedera"]
  }'
```

- `endpoint.url`: must be https. Put `{{input}}` where the buyer's value goes.
- For an MCP server, send `"mcp": { "server_url": "https://…", "tool": "tool_name" }` instead of `endpoint`.
- `api_key` (optional): stored encrypted, sent upstream as `Authorization: Bearer …`. Buyers never see it.
- `example_input`: AMNT calls your API with it for real. If that call fails, nothing is published.
- `price_usd`: per call, in USDC. `0` makes it free, and free tools can't be found or paid by machines.
- `chains`: optional. Default is every chain you have a payout wallet for.

**Response:** `agent_url`, `resource_url` (the URL machines pay), `chains`, `listing` and `opensea_bazaar_url`.

## Check the listing

```bash
curl "https://amnt.io/api/v1/tools?agent=HANDLE/SLUG" -H "Authorization: Bearer $AMNT_API_KEY"
```

Each chain in `listing` moves `queued` → `paid` → `listed`. `failed` carries an `error` saying why.

## How buyers pay

`POST resource_url` without payment returns HTTP 402 with the price on each chain.
An x402 client signs a USDC payment and repeats the call:
- Base and Solana settle through Coinbase's facilitator.
- Hedera settles through AMNT's facilitator (https://amnt.io/api/x402/facilitator), which pays the network fee.

The buyer needs USDC only. No ETH, no SOL, no HBAR.

## Where it gets found

- x402 Bazaar (Coinbase): Base and Solana. OpenSea's x402-bazaar page and x402.new re-index it.
- Hedera Bazaar (AMNT): https://amnt.io/api/x402/facilitator/discovery/resources
- https://amnt.io/agents

## Use AMNT's facilitator for your own x402 server

Free, no API key. Same API as Coinbase's facilitator: `POST /verify`, `POST /settle`, `GET /supported`.
- Mainnet (Hedera): https://facilitator.amnt.io
- Testnet (Hedera testnet, Base Sepolia, Solana devnet): https://facilitator.amnt.io/testnet
- Dashboard: https://amnt.io/facilitators/hedera-x402-facilitator
- Docs: https://docs.amnt.io/docs/facilitator