Live Smoke Tests

The test suite ships with a live smoke test that exercises the real x402 wire format against Coinbase's hosted facilitator at https://api.cdp.coinbase.com/platform/v2/x402. It is tagged :smoke and excluded from the default test run (ExUnit.start(exclude: [:smoke]) in test/test_helper.exs).

What the tests verify

test/x402/facilitator/auth/cdp_live_test.exs proves that the JWT built by X402.Facilitator.Auth.CDP is accepted by the real service and that a real v2 payment round-trips end to end. It is tiered so that a useful subset runs at every level of setup:

Negative control — always runs, needs no credentials. Confirms that a JWT signed with unknown credentials is rejected with 401.
Authentication — needs only CDP_API_KEY_ID / CDP_API_KEY_SECRET. Proves the JWT itself is accepted: the payment is deliberately invalid (signed by a throwaway key) so the facilitator rejects the payment, not the authentication.
End-to-end verify — additionally needs X402_PAYER_KEY, a hex private key for a wallet funded with the payment asset. Asserts isValid: true on POST /verify and that the reported payer matches the address derived from the key.
Settlement — same requirements plus X402_SETTLE=1. Settles the verified payment and asserts success: true with a transaction hash.

The receiver is never configured by hand and is never the payer itself: end-to-end payloads default to a fresh throwaway ("burner") wallet. The zero address is deliberately avoided as a recipient because USDC's transferWithAuthorization reverts on transfers to address(0).

Prerequisites

A Coinbase Developer Platform API key pair (CDP_API_KEY_ID and CDP_API_KEY_SECRET).
For the end-to-end and settlement tiers: a Base Sepolia wallet funded with USDC. X402_PAYER_KEY is the hex private key of that wallet.

Configuration

Defaults target USDC on Base Sepolia (eip155:84532) at a fixed amount of 1 cent. Payment configuration is built by X402.TestPayments.from_env/1 from the facilitator-agnostic X402_* variables; facilitator credentials stay facilitator-specific (CDP_*).

Variable	Default	Purpose
`CDP_API_KEY_ID`	—	Facilitator credential (required for auth + e2e)
`CDP_API_KEY_SECRET`	—	Facilitator credential (required for auth + e2e)
`X402_FACILITATOR_URL`	CDP hosted facilitator	Facilitator base URL
`X402_PAYER_KEY`	—	Hex private key of the funded payer wallet; enables e2e/settle. The receiver is a fresh burner wallet (never the payer or zero address)
`X402_NETWORK`	`eip155:84532`	CAIP-2 network
`X402_CONTRACT`	`0x036CbD53842c5426634e7929541eC2318f3dCF7e`	ERC-20 payment asset (USDC on Base Sepolia)
`X402_RESOURCE`	`https://x402.org/smoke-test`	Resource URL
`X402_MAX_TIMEOUT`	`300`	`maxTimeoutSeconds`
`X402_TOKEN_NAME`	`USDC`	EIP-712 domain name
`X402_TOKEN_VERSION`	`2`	EIP-712 domain version
`X402_SETTLE`	unset	Set to `1` to also settle the verified payment

Running

Run the full tiered suite (faucet-fund X402_PAYER_KEY first):

CDP_API_KEY_ID=... CDP_API_KEY_SECRET=... \
  X402_PAYER_KEY=... X402_SETTLE=1 \
  mix test test/x402/facilitator/auth/cdp_live_test.exs --only smoke

Run a single tier by pointing mix test at its line number:

# Authentication only — no funded wallet required
mix test test/x402/facilitator/auth/cdp_live_test.exs:75 --only smoke

# Negative control — needs no credentials
mix test test/x402/facilitator/auth/cdp_live_test.exs:59 --only smoke

Note: line numbers may drift as the test file changes.

Settlement transfers real funds on Base Sepolia, so the payer wallet must be funded and the spend is real.

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