Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com offers a suite of pay-per-request APIs accessible via the x402 payment protocol on the Base network. The `/api/v3/admin` endpoint is labeled "Premium API Access" and requires a USDC payment of up to $0.02 per call (20,000 base units of USDC with 6 decimals). No API keys, rate limits, or upfront commitments are needed — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader platform advertises endpoints across four categories: Data & Analytics (metrics, reports, data export, insights), AI & Machine Learning (sentiment analysis, text summarization, classification, embeddings), Finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and Infrastructure utilities (geocoding, validation, conversion, generation). All listed endpoints share the same $0.02/request pricing. However, the specific `/api/v3/admin` endpoint's functionality is not documented beyond the label "Premium API Access," so its exact capabilities are unclear.
Payment settles in USDC (contract 0x8335…2913) on Base to address 0x1A2B…85F3, with a 300-second timeout. The endpoint accepts POST requests and returns application/json. Documentation pages (/docs, /pricing, /README) all resolve but display only a "Connect wallet" prompt, providing no further technical detail about request/response schemas or endpoint behavior.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven API consumption without pre-registration or API key management
- —Programmatic access to data, AI, finance, or utility endpoints with instant crypto settlement
Fit
Best for
- —Developers or agents wanting keyless, pay-as-you-go API access
- —x402-compatible clients on the Base network
- —Low-friction micropayment API consumption without subscriptions
Not for
- —Users who need detailed API documentation or OpenAPI schemas before integrating
- —High-volume consumers who prefer subscription-based pricing
- —Callers who cannot settle payments in USDC on Base
Quick start
curl -X POST https://lowpaymentfee.com/api/v3/admin \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>" \
-d '{}'Endpoint
Quality
The x402 challenge is live and well-formed, confirming the endpoint exists and accepts USDC on Base at $0.02/call. However, there is no OpenAPI schema, no request/response examples, and all documentation pages return only a wallet-connect prompt. The actual functionality behind 'Premium API Access' at /api/v3/admin is undocumented, making this effectively a stub listing.
Warnings
- —The exact functionality of /api/v3/admin is not documented — 'Premium API Access' is the only description available.
- —All documentation pages (/docs, /pricing, /README, /api) render only a 'Connect wallet' prompt with no technical content.
- —No OpenAPI spec, request schema, or response schema is available.
- —The relationship between /api/v3/admin and the other advertised v1/v2 endpoints is unclear.
Citations
- —The endpoint returns a 402 x402 challenge requiring USDC payment on Base with maxAmountRequired of 20000 base units (=$0.02)https://lowpaymentfee.com/api/v3/admin
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v3/admin
- —Platform advertises $0.02/request pricing with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Available API categories include Data & Analytics, AI & Machine Learning, Finance & Web3, and Infrastructurehttps://lowpaymentfee.com
- —Documentation pages display only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs