x402-rebooker

The cancel-worse-book-better move, automated. Post a booking you already hold; one paid call scans live inventory for the same trip and returns a signed improvement report — ranked candidates, savings net of your cancellation fee, and the exact order to rebook in.

USDC on BaseUSDC on SolanaHTTP 402Apache-2.0AmadeusRIDBsigned reports

Pay on either rail — your client picks. Every 402 challenge lists USDC on Base and USDC on Solana at the same price.

git clone https://github.com/nirholas/x402-rebooker && cd x402-rebooker
npm install && cp .env.example .env   # pre-filled — runs with no edits
npm run dev                            # http://localhost:4043

GitHub Tutorial API reference For AI agents skill.md .well-known/x402

Pricing

Route	Price	Returns
`POST /scan`	$0.01	Signed report: candidates, savings, rebookSteps, verdict
`GET /sources`	free	Which inventory providers are live here
`POST /verify`	free	Signature check for any report
`GET /healthz`	free	Liveness + accepted rails

Payment rails

USDC on Base

EIP-3009 transferWithAuthorization, signed in the wallet. Nothing on-chain until the facilitator settles.

network: base-sepolia (default) · base
payTo: 0x40252CFDF8B20Ed757D61ff157719F33Ec332402
facilitator: https://x402.org/facilitator

USDC on Solana

Fee-sponsored SPL transferChecked. The facilitator's feePayer covers the SOL fee — you need only USDC.

network: solana (default) · solana-devnet
payTo: WwwuGbqHrwF5RG89KhUbmRWEvjnRH9k5kVM5p7T3WwW
facilitator: https://facilitator.payai.network

A rail with no configured address is dropped from the challenge instead of failing the request, so a single-rail deployment is a one-line change.

How a paid call works

1 · RequestPOST /scan with the booking you hold

→

2 · 402accepts[]: Base and Solana, same price

→

3 · Paypick a rail, sign, send X-PAYMENT

→

4 · 200signed report in-body + X-PAYMENT-RESPONSE

It tells you to hold

A scanner that always finds savings is a sales pitch. This one ranks the worse options alongside the better ones, subtracts your cancellation fee before claiming a win, and returns verdict: "hold" whenever nothing clears the threshold you set:

{
  "savings": { "grossUsd": 145.31, "cancellationFeeUsd": 75, "netUsd": 70.31, "pct": 17.1 },
  "verdict": "rebook",
  "reason": "Best option nets $70.31 after a $75 cancellation fee, clearing your $25 threshold.",
  "best": {
    "label": "B6 621 · nonstop · departs 2026-09-14T15:00",
    "improvements": ["$145.31 cheaper than what you paid", "1 fewer stop(s)"],
    "tradeoffs": ["different carrier (B6 vs AA) — loyalty status may not carry"]
  }
}

Every candidate carries tradeoffs as well as improvements, and rebookSteps always puts book the replacement first ahead of cancel the old booking — the one irreversible mistake in this whole move.

Real inventory, honest fallbacks

Domain	Provider	Live when	Otherwise
flight	Amadeus `/v2/shopping/flight-offers`	`AMADEUS_CLIENT_ID` + `AMADEUS_CLIENT_SECRET`	deterministic fixtures
hotel	Amadeus `/v3/shopping/hotel-offers`	same	deterministic fixtures
campsite	RIDB `/facilities`	`RIDB_API_KEY`	deterministic fixtures

Both keys are free, and neither is required to run the service. Fixture-backed reports say so in source, live and notes — you will never mistake one for a real scan. A live lookup that fails degrades to fixtures with a note rather than failing the paid call, so a scan you paid for always returns a report.