x402-gated API platform on Base offering data, AI, finance, and utility endpoints at $0.02/request.
What it does
lowpaymentfee.com is an x402-protocol API platform that gates access to a broad set of endpoints behind per-request micropayments settled in USDC on the Base network. The specific endpoint at `/api/v1/trades/120` is labeled "Premium API Access" and costs up to $0.02 per call (maxAmountRequired of 20,000 base units of USDC, which has 6 decimals = $0.02). 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 platform advertises four endpoint 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 the same $0.02/request price point. However, the specific `/api/v1/trades/120` endpoint does not clearly map to any of the documented categories — it may be a trade-data or financial endpoint, but its exact functionality is not documented.
The platform accepts POST requests and returns JSON responses. Payment is settled to address `0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3` using USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`) on Base. The x402 challenge was successfully captured with version 1 of the protocol, confirming the endpoint is live. Documentation pages beyond the landing page returned only a "Connect wallet" prompt with no additional technical detail.
Capabilities
Use cases
- —Fetching trade or financial data on a pay-per-request basis without API key management
- —Agent-driven workflows that need instant, keyless access to data endpoints
- —Prototyping integrations where per-call pricing avoids subscription overhead
Fit
Best for
- —Developers wanting zero-commitment, pay-as-you-go API access
- —AI agents that can settle x402 micropayments on Base
- —Use cases requiring low-cost ($0.02) individual API calls
Not for
- —High-volume consumers who need bulk/subscription pricing
- —Users without a Base-compatible wallet or USDC holdings
- —Anyone needing detailed API documentation or guaranteed SLAs
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/trades/120 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-proof>"Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge, and pricing is clear ($0.02 USDC on Base). However, there is no documentation for the /api/v1/trades/120 endpoint specifically — its request/response schema, purpose, and parameters are unknown. Docs pages returned only 'Connect wallet' with no technical content.
Warnings
- —The /api/v1/trades/120 endpoint is not listed among the documented API categories on the landing page — its exact functionality is unclear.
- —All documentation, pricing, and README pages beyond the homepage returned only 'Connect wallet' with no usable content.
- —No OpenAPI spec, request schema, or response schema is available for this endpoint.
- —No examples of request bodies or response payloads are documented anywhere.
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/trades/120
- —USDC asset address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/trades/120
- —All listed endpoints are priced at $0.02/request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com
- —Platform offers Data & Analytics, AI & ML, Finance & Web3, and Infrastructure endpoint categorieshttps://lowpaymentfee.com