Pay-per-call premium API access on Base via x402 — $0.02/request in USDC.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints gated by the x402 payment protocol. The specific endpoint at `/api/v1/charges/299` is labeled "Premium API Access" and accepts POST requests. Payment is settled on the Base network in USDC (contract 0x8335…2913) with a maximum charge of 20,000 base units, which equals $0.02 per request (USDC uses 6 decimals). No API keys, rate limits, or upfront commitments are required — callers simply attach an X-PAYMENT header with a valid x402 payment proof.
The broader lowpaymentfee.com 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.
Documentation is extremely sparse — the /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawled material. The endpoint is confirmed live (returns a proper 402 challenge), but without documentation it is unclear what request body this specific `/charges/299` endpoint expects or what response payload it returns.
Capabilities
Use cases
- —Accessing premium API functionality with per-request USDC micropayments on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Programmatic access without subscription commitments or rate limits
Fit
Best for
- —Developers who want zero-commitment, pay-per-use API access
- —AI agents with x402-compatible payment capabilities
- —Users already holding USDC on the Base network
Not for
- —Users who need detailed API documentation or request/response schemas before integrating
- —High-volume consumers who prefer subscription-based pricing for cost predictability
Quick start
# The endpoint returns 402 with an x402 challenge.
# Attach a valid X-PAYMENT header (x402 proof) to pay $0.02 in USDC on Base.
curl -X POST https://lowpaymentfee.com/api/v1/charges/299 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Endpoint
Quality
The endpoint is confirmed live with a valid 402 challenge and clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, and all documentation pages are empty stubs. The purpose and behavior of this specific /charges/299 endpoint are undocumented, making this effectively a stub listing.
Warnings
- —No API documentation available — /docs, /api, /pricing, and /README pages all show only 'Connect wallet' with no technical content.
- —No OpenAPI or schema definition found; request body and response format for /api/v1/charges/299 are unknown.
- —The specific functionality behind 'Premium API Access' at /charges/299 is not described anywhere in the crawled material.
- —The broader platform lists many endpoint categories (AI, finance, data, etc.) but none have documented schemas or examples.
Citations
- —Endpoint returns 402 with x402 challenge, maxAmountRequired 20000 USDC on Base networkhttps://lowpaymentfee.com/api/v1/charges/299
- —All endpoints priced at $0.02/request with no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/charges/299