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api.delx.ai x402 factorial
https://api.delx.ai/api/v1/x402/factorial
answers 402
Factorial (n≤20). Call for combinatorics demos and small counting problems with an explicit n cap. Returns n! for n up to 20; larger n returns a structured error. $0.001 USDC per successful call via x402 on Base—deterministic first-party JSON, no API key, no subscription, and nothing is billed on structured validation errors.
We sent a real
POST request to this endpoint and it
answered 402 with payment requirements we could parse.
- Price
- $0.001
- Network
- base
- Pay to
- 0x9f8bd9875b3E0b632a24A3A7C73f7787175e73A2
- Spec dialect
- v2 (declares x402Version 2)
- Transport
- PAYMENT-REQUIRED header
- HTTP method
- POST
- Response latency
- 169 ms
- Payment options
- 3 usable of 3
- Last checked
- 2026-09-06T01:17:43.085Z (19d ago)
- Category
- ai-inference
Re-check it yourself:
curl "https://api.the402.dev/validate?url=https%3A%2F%2Fapi.delx.ai%2Fapi%2Fv1%2Fx402%2Ffactorial"