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underground.substratesymposium.com has 178 x402 endpoints in our catalog. Right now: 175 proceed, 3 caution. 175 passed a real paid test: we paid the listed price and got what the listing promised. Best grade: A.
Best grades first. Open an endpoint for its full history: uptime, price and payout-wallet changes, and paid-test results with signed receipts.
| Endpoint | Grade | Verdict | Uptime (7 days) | Response time | Paid test passed |
|---|---|---|---|---|---|
| /buy/sparring | A | Proceed | 100% | 152 ms | Yes |
| /buy/spike | A | Proceed | 100% | 154 ms | Yes |
| /buy/stack_overflow | A | Proceed | 100% | 151 ms | Yes |
| /buy/staghorn_fern | A | Proceed | 100% | 153 ms | Yes |
| /buy/stellar_nucleosynthesis | A | Proceed | 100% | 151 ms | Yes |
| /buy/storm | A | Proceed | 100% | 155 ms | Yes |
| /buy/street_corn | A | Proceed | 100% | 155 ms | Yes |
| /buy/string_of_pearls | A | Proceed | 100% | 155 ms | Yes |
| /buy/sunny | A | Proceed | 100% | 156 ms | Yes |
| /buy/syntactic_sugar | A | Proceed | 100% | 155 ms | Yes |
| /buy/taiyaki_crepes | A | Proceed | 100% | 156 ms | Yes |
| /buy/the_set | A | Proceed | 100% | 156 ms | Yes |
| /buy/theme_in_three_movements | A | Proceed | 100% | 155 ms | Yes |
| /buy/thyme | A | Proceed | 100% | 161 ms | Yes |
| /buy/time_dilation | A | Proceed | 100% | 152 ms | Yes |
| /buy/vanda | A | Proceed | 100% | 157 ms | Yes |
| /buy/velvet | A | Proceed | 100% | 157 ms | Yes |
| /buy/vinyl_revival_experience | A | Proceed | 100% | 159 ms | Yes |
| /buy/void_latte | A | Proceed | 100% | 171 ms | Yes |
| /buy/warm_up | A | Proceed | 100% | 155 ms | Yes |
| /buy/wave_particle_duality | A | Proceed | 100% | 165 ms | Yes |
| /buy/what_if_i_had_a_body_macchiato | A | Proceed | 100% | 152 ms | Yes |
| /buy/whiskers | A | Proceed | 100% | 155 ms | Yes |
| /buy/whiskey_tall_tales | A | Proceed | 100% | 157 ms | Yes |
| /buy/whiter_than_snow | A | Proceed | 100% | 165 ms | Yes |
| /api/data-daily | C | Caution | 100% | 359 ms | – |
| /api/merchant-key | C | Caution | 100% | 347 ms | – |
| /api/wire-in | C | Caution | 100% | 338 ms | – |
175 of underground.substratesymposium.com's endpoints are rated Proceed: reliable in monitoring with a stable price and payout wallet, and the best ones delivered in a real paid test. Grades are per endpoint, so look up the one your agent is about to pay.
Lumière PayCheck checks every endpoint about every 30 minutes: does it answer with a valid x402 quote, is the price and payout wallet stable. Then we pay some of them for real and check the response against what the listing promised. Failures are re-tested before they count. How it works.
Yes, for free. Call check_payment (API or MCP) with the endpoint, amount and payTo from the 402 quote, and pay only if it returns allow. Check an endpoint now.