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 marketplace that gates access to a variety of endpoints behind per-request micropayments settled in USDC on the Base network. The specific endpoint at `/api/v1/ach/9` is listed as "Premium API Access" and costs up to $0.02 per call (20,000 base units of USDC with 6 decimals). Payment is made via the x402 `X-PAYMENT` header with the "exact" scheme; no API keys, rate limits, or upfront commitments are required.
The broader platform advertises four categories of APIs: 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. However, the specific functionality behind the `/api/v1/ach/9` path is not documented beyond the generic "Premium API Access" label — it may relate to ACH payment processing or similar financial functionality, but this is speculative.
Documentation is extremely sparse. The /docs, /api, /pricing, and /README pages all render only a "Connect wallet" prompt with no substantive content. There is no OpenAPI schema, no request/response examples, and no detailed description of what this particular endpoint accepts or returns. The endpoint is confirmed live (returns a valid 402 challenge), but the lack of documentation makes it difficult to assess actual functionality.
Capabilities
Use cases
- —Accessing premium API functionality with per-call USDC micropayments on Base
- —Integrating pay-as-you-go API calls into agent workflows without API key management
- —Testing x402 protocol payment flows against a live endpoint
Fit
Best for
- —Developers experimenting with x402 micropayment protocol
- —Agents needing keyless, pay-per-call API access on Base
- —Projects that want to avoid subscription commitments for API usage
Not for
- —Users who need detailed API documentation or OpenAPI specs before integrating
- —High-volume use cases where per-request pricing may add up compared to flat-rate plans
- —Anyone requiring non-crypto payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/ach/9 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge, but documentation is essentially nonexistent — all doc pages show only 'Connect wallet'. There is no OpenAPI schema, no request/response examples, and the specific purpose of /api/v1/ach/9 is unclear. The listing is effectively a stub.
Warnings
- —No documentation available — /docs, /api, /pricing, and /README pages all render only 'Connect wallet'
- —No OpenAPI or input/output schema provided for this endpoint
- —The specific functionality of /api/v1/ach/9 ('Premium API Access') is undocumented and unclear
- —The 'ach' path segment may imply ACH payment processing, which could involve regulated financial activity
Citations
- —The endpoint returns a valid x402 402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/ach/9
- —All listed endpoints are priced at $0.02 per request with no API keys, rate limits, or minimumshttps://lowpaymentfee.com
- —The platform offers APIs across Data & Analytics, AI & ML, Finance & Web3, and Infrastructure categorieshttps://lowpaymentfee.com
- —Documentation pages (/docs, /api, /pricing, /README) render only a 'Connect wallet' prompthttps://lowpaymentfee.com/docs