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 broad catalog of pay-per-request APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation). All endpoints are priced at $0.02 per request, settled in USDC on the Base network.
The specific endpoint `/api/v1/payments/78` is labeled "Premium API Access" and accepts POST requests. The x402 challenge confirms it is live, requesting a maximum of 20,000 base units of USDC (0.02 USD, since USDC uses 6 decimals) per call, paid to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` on Base. No API keys or rate limits are advertised — access is gated purely by the x402 payment header.
Documentation is extremely sparse. The docs, API, pricing, and README pages all render only a "Connect wallet" prompt with no additional content. There is no OpenAPI schema, no request/response examples, and no description of what this particular endpoint (`/payments/78`) actually returns or what input it expects beyond a POST with a payment header. The site's landing page lists many endpoint paths but provides no technical documentation for any of them. Prospective users should be aware that the actual functionality behind this endpoint is unclear from available materials.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API keys
- —Programmatic pay-as-you-go access to data, AI, finance, or utility endpoints
Fit
Best for
- —Developers wanting keyless, pay-per-call API access settled in USDC
- —AI agents that can handle x402 payment challenges autonomously
- —Users who prefer crypto micropayments over subscription billing
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —Anyone without a Base-compatible USDC wallet
- —High-volume consumers who would benefit from bulk pricing or subscriptions
Quick start
# The endpoint returns 402 with an x402 challenge.
# Supply a valid X-PAYMENT header (x402 v1, USDC on Base) to access.
curl -X POST https://lowpaymentfee.com/api/v1/payments/78 \
-H 'Content-Type: application/json' \
-H 'X-PAYMENT: <x402-payment-token>'Endpoint
Quality
The x402 challenge is live and pricing is clear ($0.02 USDC on Base), but there is zero documentation on what this endpoint actually does, no request/response schema, and no examples. The docs pages are empty beyond a wallet-connect prompt. This is effectively a stub listing.
Warnings
- —No documentation available — docs, API, pricing, and README pages all show only 'Connect wallet'
- —No OpenAPI or output schema describing what /api/v1/payments/78 returns
- —The specific functionality of this endpoint (labeled 'Premium API Access') is unknown from available materials
- —No request body schema or example responses provided anywhere on the site
Citations
- —The endpoint returns a 402 x402 challenge requesting 20,000 base units of USDC on Base (=$0.02)https://lowpaymentfee.com/api/v1/payments/78
- —All endpoints are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —The site offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/payments/78