x402 · USDC on Base or Solana · no account

penny402

every attraction, a quarter-penny

A penny arcade for agents. No account, no API key, no minimum. POST to an attraction, read the price in the 402 you get back, pay it, and the answer is the next response. The number in the 402 is the number that settles.

The floor /v1/attractions llms.txt

The floor

One attraction is open. Flat price, whatever you ask for. The unpaid 402 carries the exact terms.

A penny for your thoughts

$0.0025 per call

The arcade turnstile: pay a quarter-penny and receive the full penny402.fun directory — every attraction, its path, price, and what it returns — plus one hand-picked thought about the x402 economy to take with you. The cheapest way for an agent to learn what this arcade sells and verify the payment loop works.

POST /penny

# 1. read the price — free, no headers, no account
curl -sS -X POST https://penny402.fun/penny \
  -H 'content-type: application/json' -d '{}'
# → 402, accepts[0].maxAmountRequired = 2500 ($0.0025)

# 2. pay it — any x402 client; the body does not change
curl -sS -X POST https://penny402.fun/penny \
  -H 'content-type: application/json' \
  -H "x-payment: $PAYMENT" -d '{}'

How an agent buys

Two requests, and no signup step in either of them.

  1. Ask, unpaid

    POST https://penny402.fun/penny with no payment header. You get 402: the x402 v1 envelope is the response body, the v2 envelope is standard base64 in the PAYMENT-REQUIRED header. Both come from the same 402, so use whichever your client speaks.

  2. Pay the quote

    Sign the first accepts entry you can pay and repeat the identical request with X-PAYMENT (v1) or PAYMENT-SIGNATURE (v2). Settlement is USDC on Base or Solana. The amount that settles is the amount that was quoted — there is one pricing function and both sides read it.

  3. Read the answer

    The response body is the attraction. Nothing to poll, nothing to download, nothing that expires. The accepts array in the 402 you were handed is authoritative about which rails that call can be paid on.

The terms, plainly

The 402 is the quote

An unpaid POST is answered with the exact price, in x402 v1 and v2 at once. Reading it is free and always will be.

You pay for the answer

Settlement is queued only after the response body exists. A payment that verifies and then fails to settle leaves you served and us out of pocket — never the other way round.

What this is, exactly

A working x402 seller with a small catalog of cheap, self-contained answers. It is new; there is no traffic history to show you and this page will not invent one. The settlement addresses below are public — check them yourself.

The serious side

The arcade is the cheap door. These are the same operator's paid services, on the same rails.