Pay-per-call API access on Base via x402 — $0.02/request in USDC, no keys required.
What it does
lowpaymentfee.com hosts a collection of pay-per-request API endpoints gated by the x402 protocol on the Base network. The specific endpoint `/api/v1/keys/76` is listed as "Premium API Access" and costs up to 20,000 base units of USDC (0x8335…2913 on Base, 6 decimals), which equals $0.02 per request. Payment is made inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required.
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 endpoints are listed at $0.02 per call. This particular endpoint (`/api/v1/keys/76`) does not clearly map to any of those named categories — its exact functionality beyond "Premium API Access" is not documented.
The endpoint is live and returns a valid x402 challenge (version 1, scheme "exact") when called without payment. It accepts POST requests, settles in USDC on Base, and has a payment timeout of 300 seconds. No OpenAPI schema, detailed documentation, or example responses were found in the crawl.
Capabilities
Use cases
- —Accessing premium API functionality with per-call USDC micropayments on Base
- —Agent-driven workflows that need keyless, on-demand API access
- —Programmatic access without subscription commitments or rate limits
Fit
Best for
- —Developers who want zero-signup, pay-as-you-go API access
- —AI agents with Base USDC wallets needing on-demand endpoints
- —Low-volume or bursty usage patterns where subscriptions are wasteful
Not for
- —Users who need detailed API documentation or guaranteed SLAs before purchasing
- —High-volume consumers who would benefit from bulk pricing or subscriptions
- —Developers without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/keys/76 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is live and returns a valid x402 challenge, but there is no OpenAPI schema, no documentation of request/response formats, and the exact functionality of this specific endpoint (/api/v1/keys/76) is unclear beyond the generic label 'Premium API Access'. Pricing is clear but everything else must be guessed.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown
- —The exact functionality of /api/v1/keys/76 ('Premium API Access') is not described anywhere in the crawled content
- —No example requests or responses are available
- —The /api, /pricing, and /README pages all returned only a 'Connect wallet' prompt with no useful content
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/keys/76
- —USDC contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/keys/76
- —All listed endpoints cost $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —The platform offers endpoints across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com