the402 endpoint detail

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attester.dev symbol exists

https://attester.dev/v1/symbol/exists

payable

Deterministic symbol existence for PyPI and npm packages: functions, classes, methods, constants with signatures and deprecation flags, extracted from real artifacts. Negative answers include closest matches and signed proof. $0.005 USDC per check.

We sent a real POST request to this endpoint and it answered 402 with payment requirements we could parse.
Price
$0.005
Network
base
Pay to
0x57407D691F755cAa107647718F3582a8A87467dD
Spec dialect
v2 (declares x402Version 2)
Transport
PAYMENT-REQUIRED header
HTTP method
POST
Response latency
6238 ms
Payment options
1 usable of 1
Last checked
2026-08-10T09:10:31.375Z (1d ago)
Category
web-scraping

Re-check it yourself:
curl "https://api.the402.dev/validate?url=https%3A%2F%2Fattester.dev%2Fv1%2Fsymbol%2Fexists"