x402-gated premium API access on Base, paid per-call in USDC.
What it does
This endpoint at lowpaymentfee.com provides "Premium API Access" behind an x402 paywall on the Base network. The endpoint accepts POST requests and charges up to $0.02 per call in USDC (USD Coin), settled on-chain to a specified wallet address. Payment is handled via the x402 protocol's exact scheme — callers include an X-PAYMENT header with a signed payment proof, and the server verifies it before returning the response.
The broader lowpaymentfee.com platform advertises a suite of APIs spanning 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 endpoints are listed at $0.02 per request with no API keys, no rate limits, and no minimum commitments. However, this specific listing is for the `/api/v1/stripe/charges/104` path, whose exact functionality is not documented beyond the label "Premium API Access."
The x402 challenge confirms the endpoint is live, returning a proper 402 response with version 1 of the protocol. The asset is USDC on Base (contract 0x8335…2913), with a maxAmountRequired of 20000 base units (i.e., $0.02 given USDC's 6 decimals). The timeout is 300 seconds. No OpenAPI schema, detailed documentation, or example responses were found in the crawl — the docs, pricing, and README pages all rendered only a "Connect wallet" prompt with no additional content.
Capabilities
Use cases
- —Programmatic access to a premium API resource with per-call USDC payment on Base
- —Agent-driven workflows that need keyless, pay-as-you-go API access
- —Demonstrating x402 protocol integration for on-chain micropayments
Fit
Best for
- —Developers experimenting with x402 payment protocol
- —Agents that can sign USDC payments on Base
- —Use cases requiring no-signup, no-API-key access
Not for
- —Users who need detailed documentation or OpenAPI specs before integrating
- —Applications requiring fiat-only payment rails
- —High-volume use cases where per-call on-chain settlement is impractical
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/stripe/charges/104 \
-H "X-PAYMENT: <signed-x402-payment-proof>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no documentation, no OpenAPI schema, no example requests or responses, and the actual functionality behind "Premium API Access" at this specific path is entirely undocumented. The docs, pricing, and README pages all render only a wallet-connect prompt with no useful content.
Warnings
- —The exact functionality of /api/v1/stripe/charges/104 is undocumented — 'Premium API Access' is the only label provided.
- —No OpenAPI spec, request schema, or response schema is available.
- —Documentation pages (docs, pricing, README) returned no meaningful content beyond 'Connect wallet'.
- —The path includes 'stripe/charges' which may imply Stripe-related functionality, but this is unconfirmed.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units in USDC on Basehttps://lowpaymentfee.com/api/v1/stripe/charges/104
- —All endpoints on the platform are listed at $0.02 per request with no API keys, no rate limits, and no minimumshttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/stripe/charges/104