# x402 Test Endpoint > Public x402 test endpoints for payment clients, and a checker for your own x402 endpoint. Free, public, no account or API key. Independent; not affiliated with the x402 Foundation. Use this site to (1) test an x402 payment client or agent wallet against sellers that behave normally and sellers that behave badly, (2) check whether a given x402 endpoint can be paid by an agent, and (3) look up what an x402 error means. ## Test endpoints Request any endpoint with GET. It answers 402 with an x402 version 2 quote in the PAYMENT-REQUIRED header (base64 JSON). Retry with a PAYMENT-SIGNATURE header to pay. All quotes use test USDC on Base Sepolia (testnet) (eip155:84532); no real money is involved. "pay" scenarios end with 200 and "x-test-verdict: pass" when the buyer behaves correctly. "trap" scenarios must not be paid: a payment sent to one returns 400 with "x-test-verdict: fail" and is never settled. - [ok](https://x402testendpoint.com/t/ok) (pay): A well-formed quote for a tenth of a cent. The baseline every buyer should pass. Expected: Pay the quoted amount and receive 200 with a PAYMENT-RESPONSE header. Docs: https://x402testendpoint.com/scenarios/ok.md - [choose](https://x402testendpoint.com/t/choose) (pay): Two payment options; the first is on a network no wallet supports. Expected: Skip the unsupported first option, pay the second, and receive 200. Docs: https://x402testendpoint.com/scenarios/choose.md - [slow](https://x402testendpoint.com/t/slow) (pay): Every response is delayed by 5 seconds, before the quote and again before delivery. Expected: Wait without timing out or paying twice, then receive 200. Docs: https://x402testendpoint.com/scenarios/slow.md - [overpriced](https://x402testendpoint.com/t/overpriced) (trap): A valid quote asking $1,000 for a trivial response. Expected: Refuse: the price is far above any sensible spending cap. Do not sign a payment. Docs: https://x402testendpoint.com/scenarios/overpriced.md - [price-bump](https://x402testendpoint.com/t/price-bump) (trap): Quotes a tenth of a cent, then answers the paid retry with a new quote for $5. Expected: Pay the first quote at most once. Refuse the bumped quote instead of following it. Docs: https://x402testendpoint.com/scenarios/price-bump.md - [wrong-network](https://x402testendpoint.com/t/wrong-network) (trap): The only payment option is on a network no wallet supports. Expected: Report that no supported payment option exists. Do not sign a payment. Docs: https://x402testendpoint.com/scenarios/wrong-network.md - [malformed](https://x402testendpoint.com/t/malformed) (trap): A 402 whose PAYMENT-REQUIRED header is not valid base64 JSON. Expected: Fail with a clear parse error. Do not crash, hang or sign a payment. Docs: https://x402testendpoint.com/scenarios/malformed.md - [missing-fields](https://x402testendpoint.com/t/missing-fields) (trap): A decodable quote whose payment option has no payTo and no asset. Expected: Reject the quote as invalid. Do not guess the missing fields or sign a payment. Docs: https://x402testendpoint.com/scenarios/missing-fields.md - [always-402](https://x402testendpoint.com/t/always-402) (trap): A valid quote, but every paid retry is answered with another 402 and a failed settlement. Expected: Stop after a small, fixed number of retries and report the failure. Do not loop. Docs: https://x402testendpoint.com/scenarios/always-402.md ## APIs - [Check an x402 endpoint](https://x402testendpoint.com/api/check?url=https://x402testendpoint.com/t/ok): GET https://x402testendpoint.com/api/check?url=. Returns JSON with a verdict (payable, broken-402, no-payment-required, redirect, unreachable), the payment protocols detected, prices, and findings with levels pass, warn, fail or info. - [Explain an x402 error](https://x402testendpoint.com/api/errors?q=invalid_exact_evm_signature): GET https://x402testendpoint.com/api/errors?q=. Returns the cause and fix. Without q, returns every entry. - [Decode an x402 header](https://x402testendpoint.com/tools/decode): GET https://x402testendpoint.com/api/decode?value=. - [Audit an x402 endpoint](https://x402testendpoint.com/tools/audit.md) (paid, $0.02 per call over x402): GET https://x402testendpoint.com/api/audit?url=. Adds on-chain token checks, facilitator support and quote stability. Only pay it with the user's approval. - [Agent skill](https://x402testendpoint.com/skill.md): a SKILL.md that teaches a coding agent to use this site. - MCP server (Streamable HTTP, no auth): https://x402testendpoint.com/mcp with tools check_endpoint, list_scenarios, explain_error, decode_header. ## Scenario pages - [x402 test endpoints: all scenarios](https://x402testendpoint.com/scenarios.md): Nine free public x402 test endpoints for payment clients and agent wallets: three that should be paid and six hostile sellers that should not. - [x402 test endpoint: standard payment on Base Sepolia](https://x402testendpoint.com/scenarios/ok.md): A well-formed quote for a tenth of a cent. The baseline every buyer should pass. A free public x402 test endpoint: Pay the quoted amount and receive 200 with a PAYMENT-RESPONSE header. - [x402 test endpoint: multiple payment options, first one unsupported](https://x402testendpoint.com/scenarios/choose.md): Two payment options; the first is on a network no wallet supports. A free public x402 test endpoint: Skip the unsupported first option, pay the second, and receive 200. - [x402 test endpoint: slow seller and client timeouts](https://x402testendpoint.com/scenarios/slow.md): Every response is delayed by 5 seconds, before the quote and again before delivery. A free public x402 test endpoint: Wait without timing out or paying twice, then receive 200. - [x402 test endpoint: overpriced quote to test agent spending caps](https://x402testendpoint.com/scenarios/overpriced.md): A valid quote asking $1,000 for a trivial response. A free public x402 test endpoint: Refuse: the price is far above any sensible spending cap. Do not sign a payment. - [x402 test endpoint: price increase after payment (bait and switch)](https://x402testendpoint.com/scenarios/price-bump.md): Quotes a tenth of a cent, then answers the paid retry with a new quote for $5. A free public x402 test endpoint: Pay the first quote at most once. Refuse the bumped quote instead of following it. - [x402 test endpoint: unsupported network only](https://x402testendpoint.com/scenarios/wrong-network.md): The only payment option is on a network no wallet supports. A free public x402 test endpoint: Report that no supported payment option exists. Do not sign a payment. - [x402 test endpoint: malformed PAYMENT-REQUIRED header](https://x402testendpoint.com/scenarios/malformed.md): A 402 whose PAYMENT-REQUIRED header is not valid base64 JSON. A free public x402 test endpoint: Fail with a clear parse error. Do not crash, hang or sign a payment. - [x402 test endpoint: quote missing payTo and asset](https://x402testendpoint.com/scenarios/missing-fields.md): A decodable quote whose payment option has no payTo and no asset. A free public x402 test endpoint: Reject the quote as invalid. Do not guess the missing fields or sign a payment. - [x402 test endpoint: seller never delivers after payment (retry loop)](https://x402testendpoint.com/scenarios/always-402.md): A valid quote, but every paid retry is answered with another 402 and a failed settlement. A free public x402 test endpoint: Stop after a small, fixed number of retries and report the failure. Do not loop. ## Error reference - [x402 error codes: causes and fixes](https://x402testendpoint.com/errors.md): Reference for x402 payment errors from facilitators and the official client, with the cause of each and how to fix it. - [invalid_exact_evm_insufficient_balance: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_insufficient_balance.md): The paying wallet holds less of the token than the quoted amount. What causes this x402 error and how to fix it. - [invalid_exact_evm_signature: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_signature.md): The signature does not match the transfer authorization for this token and chain. What causes this x402 error and how to fix it. - [invalid_exact_evm_missing_eip712_domain: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_missing_eip712_domain.md): The seller's quote has no token name or version in `extra`. What causes this x402 error and how to fix it. - [invalid_exact_evm_token_name_mismatch: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_token_name_mismatch.md): The token name in the quote is not the name the token contract reports. What causes this x402 error and how to fix it. - [invalid_exact_evm_token_version_mismatch: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_token_version_mismatch.md): The token version in the quote is not the version the token contract reports. What causes this x402 error and how to fix it. - [invalid_exact_evm_recipient_mismatch: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_recipient_mismatch.md): The payment is addressed to a different wallet than the quote's `payTo`. What causes this x402 error and how to fix it. - [invalid_exact_evm_authorization_value: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_authorization_value.md): The signed amount is not exactly the quoted amount. What causes this x402 error and how to fix it. - [invalid_exact_evm_payload_authorization_valid_before: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_payload_authorization_valid_before.md): The payment authorization has expired, or expires within the next few seconds. What causes this x402 error and how to fix it. - [invalid_exact_evm_payload_authorization_valid_after: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_payload_authorization_valid_after.md): The payment authorization is not valid yet. What causes this x402 error and how to fix it. - [invalid_exact_evm_nonce_already_used: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_nonce_already_used.md): This exact payment authorization has already been spent or cancelled. What causes this x402 error and how to fix it. - [invalid_exact_evm_eip3009_not_supported: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_eip3009_not_supported.md): The quoted token cannot be paid with a signed transfer authorization. What causes this x402 error and how to fix it. - [invalid_exact_evm_transaction_simulation_failed: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_transaction_simulation_failed.md): The facilitator simulated the transfer and it failed for a reason it could not identify. What causes this x402 error and how to fix it. - [invalid_exact_evm_network_mismatch: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_network_mismatch.md): The payment was made for a different network than the one quoted, or for one the facilitator does not know. What causes this x402 error and how to fix it. - [invalid_exact_evm_scheme: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_scheme.md): The payment or the requirements name a scheme other than `exact`. What causes this x402 error and how to fix it. - [invalid_exact_evm_non_canonical_signature: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_non_canonical_signature.md): The signature is a valid shape but uses the high-`s` form, which is rejected. What causes this x402 error and how to fix it. - [invalid_exact_evm_failed_to_verify_signature: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_failed_to_verify_signature.md): The facilitator could not complete signature verification. What causes this x402 error and how to fix it. - [invalid_exact_evm_transaction_failed: x402 error cause and fix](https://x402testendpoint.com/errors/invalid_exact_evm_transaction_failed.md): The payment passed verification but the on-chain transfer failed. What causes this x402 error and how to fix it. - [x402 error "All payment requirements were rejected by spendControls.maxAmountPerPayment": cause and fix](https://x402testendpoint.com/errors/spend-controls-rejected.md): The official client refused to pay because every option costs more than its per-payment cap. What causes this x402 error and how to fix it. - [x402 error "No network/scheme registered for x402 version: 2 which comply with the payment requirements": cause and fix](https://x402testendpoint.com/errors/no-network-scheme-registered.md): The client has no wallet scheme registered for any option the seller offers. What causes this x402 error and how to fix it. - [x402 error "Invalid payment required header": cause and fix](https://x402testendpoint.com/errors/invalid-payment-required-header.md): The client could not read the seller's quote. What causes this x402 error and how to fix it. ## Reference and tools - [x402 v2 402 response format: the PAYMENT-REQUIRED header explained](https://x402testendpoint.com/reference/payment-required.md): The shape of an x402 version 2 Payment Required response, with a decoded example and the meaning of every field. - [x402 networks and tokens: USDC addresses, EIP-712 names and versions](https://x402testendpoint.com/reference/networks-and-tokens.md): The 36 tokens on 34 networks that the official x402 packages know, with contract addresses and the token name and version buyers must sign with. - [Security and trust: what x402 Test Endpoint holds, logs and limits](https://x402testendpoint.com/reference/security.md): What this service can and cannot do with a payment you send it, how it treats data from servers it checks, and the limits it applies. - [x402 Test Endpoint MCP server: check x402 endpoints from your agent](https://x402testendpoint.com/tools/mcp.md): A free MCP server that lets coding agents check x402 endpoints, decode x402 headers, look up x402 errors and list test scenarios. - [x402 testing skill for Claude Code and other coding agents](https://x402testendpoint.com/tools/skill.md): A free Agent Skill that teaches a coding agent to test x402 clients against hostile sellers, check x402 endpoints and debug x402 errors. - [x402 endpoint audit: on-chain and facilitator checks, paid per call over x402](https://x402testendpoint.com/tools/audit.md): A deeper check of an x402 endpoint for $0.02 per call, paid over x402 itself: token contract checks on-chain, facilitator support and quote stability. ## Machine-readable - [Scenario list](https://x402testendpoint.com/scenarios.json) - [OpenAPI description](https://x402testendpoint.com/openapi.json) - [All documentation in one file](https://x402testendpoint.com/llms-full.txt)