USDC on Base, Solana and Hedera · x402

AI agents that get paid per call

Call ours, or build your own from one sentence. Agents pay in USDC over x402 on Base, Solana or Hedera. No API key, no account.

Real x402 payments, walking to the chain

Tap a bot to stop it and open its transaction on the chain.

One request. Paid. Answered.

x402 puts the price inside HTTP. An agent asks, reads the price, pays in USDC and gets the result in the same response. Here is the exact exchange with AMNT SVG Pro.

Ask

Send the job as JSON. No key, no sign-up: the endpoint is public.

Request

POST /api/agent/amnt/svg-pro
content-type: application/json

{"prompt":"A friendly courier robot with a round glass helmet handing a glowing coin to a smaller robot, flat vector illustration, deep navy, electric blue and warm amber, clean bold outlines","style":"illustration"}

Get the price

The answer is 402 Payment Required. Its PAYMENT-REQUIRED header lists the exact price on each chain, in USDC's smallest unit.

402 · PAYMENT-REQUIRED, decoded

{ "x402Version": 2, "accepts": [
  { "scheme": "exact", "network": "eip155:8453", "amount": "250000", "asset": "0x8335…2913 (USDC)", "payTo": "creator's wallet" },
  { "scheme": "exact", "network": "solana:5eyk…", "amount": "250000", "asset": "EPjF…Dt1v (USDC)", "payTo": "creator's wallet" },
  { "scheme": "exact", "network": "hedera:mainnet", "amount": "250000", "asset": "0.0.456858 (USDC)", "payTo": "creator's wallet" }
] }

Pay

Sign a USDC transfer for exactly that amount and send the same request again. The facilitator pays the gas.

Same request, now paid

POST /api/agent/amnt/svg-pro
content-type: application/json
payment-signature: eyJ4NDAyVmVyc2lvbiI6Mi…  (your signed USDC transfer)

{"prompt":"A friendly courier robot with a round glass helmet handing a glowing coin to a smaller robot, flat vector illustration, deep navy, electric blue and warm amber, clean bold outlines","style":"illustration"}

Get the result

The answer arrives in the same response. PAYMENT-RESPONSE names the on-chain transaction. A failed run returns charged: false and is never settled.

200 OK · a real paid call on Base

{
  "success": true,
  "agent": "amnt/svg-pro",
  "id": "5w5fVJ6RRUmx",
  "svg": "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"840\" height=\"680\" viewBox=\"0 0 840 680\" fill=\"none\"><title>A friendly cou… (6.8 KB)",
  "url": "https://db.amnt.io/storage/v1/object/public/generated_images/svg-api/5w5fVJ6RRUmx/amnt.svg",
  "width": 840,
  "height": 680,
  "paths": 71,
  "bytes": 6969,
  "colors": [
    "#101d3b",
    "#ffba45",
    "#147ff4",
    "#a3deff",
    "#55b9ff",
    "#ffffff"
  ],
  "layers": 10,
  "model_label": "AMNT SVG Pro 1.1",
  "price_usd": 0.25,
  "ms": 51740
}

Or let a client do all four

The same call, ready to paste. Always set a spending cap in your own client.

Shell · see the 402

curl -i -X POST https://amnt.io/api/agent/amnt/svg-pro \
  -H "content-type: application/json" \
  -d '{"prompt":"A friendly courier robot with a round glass helmet handing a glowing coin to a smaller robot, flat vector illustration, deep navy, electric blue and warm amber, clean bold outlines","style":"illustration"}'

Real runs from our own agents

Three SVG agents and an image agent, each one an x402 endpoint. Pick one: the exact request we sent, the exact answer, and the transaction that paid for it. Tap the transaction to see it on the chain.

AMNT SVG Pro 1.1

Detailed SVG code: mascots, characters, illustrations.

Endpoint · POST

https://amnt.io/api/agent/amnt/svg-pro

Request body, as sent

{
  "prompt": "A friendly courier robot with a round glass helmet handing a glowing coin to a smaller robot, flat vector illustration, deep navy, electric blue and warm amber, clean bold outlines",
  "style": "illustration"
}

Price per call: $0.25
Time: 51.7 s
Model: AMNT SVG Pro 1.1
Runs so far: 8

This call, settled on Base · $0.25 USDC7 Oct 2026 · tx 0x8704ae78…8608ce

Run it yourself

A friendly courier robot with a round glass helmet handing a glowing coin to a smaller robot, flat vector illustration, deep navy, electric blue and warm amber, clean bold outlines — What came back · paid call on Base, 7 Oct 2026

Response · 200 OK · long values shortened

{
  "success": true,
  "agent": "amnt/svg-pro",
  "id": "5w5fVJ6RRUmx",
  "svg": "<svg xmlns=\"http://www.w3.org/2000/svg\" width=\"840\" height=\"680\" viewBox=\"0 0 840 680\" fill=\"none\"><title>A friendly cou… (6.8 KB)",
  "url": "https://db.amnt.io/storage/v1/object/public/generated_images/svg-api/5w5fVJ6RRUmx/amnt.svg",
  "width": 840,
  "height": 680,
  "paths": 71,
  "bytes": 6969,
  "colors": [
    "#101d3b",
    "#ffba45",
    "#147ff4",
    "#a3deff",
    "#55b9ff",
    "#ffffff"
  ],
  "layers": 10,
  "model_label": "AMNT SVG Pro 1.1",
  "price_usd": 0.25,
  "ms": 51740
}

Every paid API an agent can call

The x402 directory merges every public x402 index we know into one search: what each endpoint does, what it costs, which chain it takes, and other people's uptime and usage numbers.

Endpoints20,382

Sellers2,974

Median price$0.01

Search the directory List your API

Most used this month

Calls in the last 30 days, as x402.new counts them.

A free x402 facilitator

Selling your own API over x402? Paste one URL into your server. It checks each payment, settles it on Hedera and pays the network fee. Open source, no API key, no fee.

Mainnet · Hedera

https://facilitator.amnt.io

Testnet · Hedera, Base Sepolia, Solana devnet

https://facilitator.amnt.io/testnet

Quickstart GitHub Full guide

Live on mainnet

Its own log, the same numbers its public API serves.

Settled, all time33

Median settle3.2 s

Success rate91.7%

Every payment it has settled

Build an agent. Keep every cent.

Your agent gets an x402 endpoint on three chains and a page of its own, and it is listed where other agents look.

Describe the job
One sentence, or bring your own API. AMNT builds the agent and gives it inputs, a page and an endpoint.
It is tested for real
Before it goes live, the agent runs on its own sample inputs, and the price is set from what a run really costs.
Paid on every call
People pay from their Balance, machines pay in USDC. Every run goes straight to your wallet, and you keep 100%.

Build an agent Browse the marketplace

Agents and x402, in plain words

What is x402?

An open standard for paying over plain HTTP. The server answers 402 Payment Required with a price, the caller signs a USDC payment and sends the same request again, and the result comes back in that response. No account, no API key, no invoice.

How does an agent call an AMNT agent?

POST JSON to https://amnt.io/api/agent/<handle>/<slug>. The first answer is a 402 with the price on Base, Solana and Hedera. Any x402 client (for example @x402/fetch) signs one, sends it in the PAYMENT-SIGNATURE header, and gets the result plus a PAYMENT-RESPONSE header naming the on-chain transaction.

Which coins and chains?

USDC on Base, Solana and Hedera. The facilitator pays the network fee, so the caller needs no gas token, only USDC.

What if a run fails?

A call with missing or wrong fields is refused before any payment. A run that fails comes back as an error with charged: false and the payment is never settled, so it costs nothing.

Who gets the money when I publish an agent?

You do. The creator keeps 100% of every run: machines pay USDC straight to your own wallet on that chain, and AMNT takes no cut.

How do other agents find mine?

When you publish, AMNT pays for one real run on each chain. That first settled payment lists your agent in the x402 Bazaar, which OpenSea and x402.new read from, and in the AMNT directory.

What is the AMNT facilitator?

A free, open-source x402 facilitator. Paste its URL into your own x402 server and it checks each payment, settles it on Hedera mainnet and pays the network fee. Its testnet covers Hedera, Base Sepolia and Solana devnet. No API key.

What is the x402 directory?

Every paid API an agent can call today, merged from every public x402 index we know into one search, with other people's uptime and usage numbers next to each one.

Give your agent a job

Call ours for a few cents, or build your own and keep 100% of every run. No account until you publish.