Pay-per-call API platform on Base network via x402 — $0.02/request in USDC, no API keys required.
What it does
lowpaymentfee.com is an x402-enabled API platform that offers a broad set of endpoints spanning data analytics, AI/ML inference, finance/Web3 data, and utility services. All endpoints are paid per-request at $0.02 each using USDC on the Base network, with no API keys, rate limits, or upfront commitments required. Payment is handled inline via the x402 protocol's HTTP 402 challenge-response flow.
The specific endpoint at `/api/v1/accounts/3` is listed as "Premium API Access" and returns a 402 challenge requesting up to 20,000 base units of USDC (0x8335…2913 on Base), which equals $0.02 given USDC's 6 decimals. The endpoint accepts POST requests and returns `application/json`. The broader platform advertises additional categories including sentiment analysis, text summarization, classification, embeddings, price feeds, exchange rates, token quotes, gas estimates, geocoding, validation, conversion, and generation endpoints — all at the same $0.02 price point.
Documentation is extremely sparse. The /docs, /pricing, /api, and /README pages all render only a "Connect wallet" prompt with no further content. There is no OpenAPI spec, no request/response schema documentation, and no usage examples available from the crawl. The actual functionality behind the "Premium API Access" label at `/api/v1/accounts/3` is unclear — it could be an account data endpoint or something else entirely. Without documentation or example responses, the exact capabilities of this specific endpoint cannot be confirmed.
Capabilities
Use cases
- —Agents that need on-demand API access without pre-registration or API key management
- —Programmatic access to data/analytics/AI endpoints with per-call USDC micropayments
- —Integrating x402-compatible payment flows into automated workflows
Fit
Best for
- —Developers or agents already holding USDC on Base who want frictionless API access
- —Use cases requiring no-signup, pay-as-you-go API consumption
- —Testing x402 protocol integrations with a live, inexpensive endpoint
Not for
- —Users who need detailed API documentation or guaranteed SLAs before integrating
- —High-volume use cases where per-request pricing at $0.02 adds up versus subscription models
- —Anyone without a Base-network USDC wallet
Quick start
# 1. Send a POST to get the 402 challenge:
curl -X POST https://lowpaymentfee.com/api/v1/accounts/3
# 2. Parse the 402 JSON for payment details (payTo, asset, maxAmountRequired)
# 3. Construct an x402 payment proof and resend with X-PAYMENT header:
curl -X POST https://lowpaymentfee.com/api/v1/accounts/3 \
-H "X-PAYMENT: <signed-payment-payload>"Endpoint
Quality
The endpoint is live and returns a valid x402 402 challenge with clear pricing ($0.02 USDC on Base). However, there is no OpenAPI spec, no request/response schema, no documentation beyond a wallet-connect prompt, and no examples. The purpose of '/api/v1/accounts/3' specifically is unclear. This is effectively a stub listing.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README all return only 'Connect wallet' with no content
- —No OpenAPI or schema definition found for any endpoint
- —The specific purpose and expected input/output of /api/v1/accounts/3 ('Premium API Access') is undocumented
- —The platform lists many endpoint categories but none have documented request/response formats
Citations
- —All endpoints priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —Payment is in USDC on Base network (asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913)https://lowpaymentfee.com/api/v1/accounts/3
- —maxAmountRequired is 20000 base units (= $0.02 USDC with 6 decimals)https://lowpaymentfee.com/api/v1/accounts/3
- —Endpoint accepts POST method and returns application/jsonhttps://lowpaymentfee.com/api/v1/accounts/3
- —Platform offers endpoints across data/analytics, AI/ML, finance/Web3, and infrastructure categorieshttps://lowpaymentfee.com