Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" via the x402 payment protocol. The site hosts a collection of pay-per-request APIs spanning data & analytics, AI & machine learning, finance & Web3, and infrastructure utilities, all priced at $0.02 per request. The specific endpoint `/api/v1/charges/356` is listed as "Premium API Access" and accepts POST requests settled in USDC on the Base network.
Payment is handled via the x402 exact-payment scheme. The challenge advertises a maxAmountRequired of 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. There are no API keys, no rate limits, and no minimum commitments — callers simply attach an X-PAYMENT header with a valid x402 payment proof. The timeout window is 300 seconds.
The crawled documentation pages (docs, api, pricing, README) all returned only a "Connect wallet" prompt with no further content, so the exact functionality behind this particular charge endpoint is unclear. The site's landing page groups its APIs into categories (metrics, reports, sentiment analysis, summarization, classification, embeddings, price feeds, exchange rates, geocoding, validation, conversion, generation), but the `/api/v1/charges/356` path does not map directly to any of those listed endpoints. It may be a generic charge/access endpoint or a specific resource. Without deeper documentation, the precise response payload and input parameters remain unknown.
Capabilities
Use cases
- —Programmatic access to premium API resources without subscription or API key management
- —Agent-driven pay-per-call workflows where each request is settled in USDC on Base
- —Integrating low-cost API calls into Web3 applications with on-chain payment proofs
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 payments autonomously
- —Projects already operating on the Base L2 network with USDC
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —High-volume consumers who would benefit from bulk pricing or subscriptions
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/charges/356 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI schema, no documentation beyond a wallet-connect prompt, no example request/response payloads, and the specific functionality of /api/v1/charges/356 is not explained anywhere in the crawled material. This is effectively a stub listing.
Warnings
- —The exact functionality behind /api/v1/charges/356 is undocumented — it does not match any of the named API paths on the landing page.
- —All documentation pages (docs, api, pricing, README) returned only 'Connect wallet' with no usable content.
- —No OpenAPI spec, no input/output schema, and no example responses are available.
- —The response MIME type is listed as application/json but the actual payload structure is unknown.
Citations
- —The endpoint returns a 402 x402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/356
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/charges/356
- —All APIs are priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The site offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com