x402-gated card transaction endpoint on Base, pay $0.02 per request in USDC.
What it does
This endpoint at lowpaymentfee.com provides access to a card transactions resource at `/api/v1/cards/40/transactions` via the x402 payment protocol. The endpoint is live and returns a 402 challenge requiring payment in USDC on the Base network. The maximum amount required per call is 20,000 base units of USDC (6 decimals), which equals $0.02 USD per request.
The provider's site advertises a broad catalog of x402-gated APIs spanning data & analytics, AI/ML inference (sentiment analysis, summarization, classification, embeddings), finance & Web3 (price feeds, exchange rates, token quotes, gas estimates), and infrastructure utilities (geocoding, validation, conversion, generation) — all at $0.02 per request. However, this specific listing is for the `/api/v1/cards/40/transactions` endpoint, which is labeled "Premium API Access" and appears to be a card transactions resource. No detailed documentation, request/response schemas, or example payloads are available from the crawled pages (docs, pricing, and API pages all returned only a "Connect wallet" prompt with no further content).
Payment is settled on the Base L2 network using USDC (contract `0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`). The endpoint accepts POST requests, requires no API keys, and advertises no rate limits. The x402 challenge specifies a 300-second payment timeout.
Capabilities
Use cases
- —Retrieving or submitting card transaction data via a pay-per-call model
- —Integrating card transaction lookups into agent workflows without API key management
- —Programmatic access to card transaction records settled with USDC on Base
Fit
Best for
- —Developers wanting keyless, pay-per-request card transaction access
- —AI agents that can settle x402 payments in USDC on Base
- —Prototyping integrations that need card transaction data without subscription commitments
Not for
- —Users who need detailed API documentation or response schemas before integrating
- —High-volume production workloads where per-request pricing may not be cost-effective
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/cards/40/transactions \
-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 documentation, no request/response schema, and no examples available. The purpose of the 'cards/40/transactions' resource is unclear beyond the generic 'Premium API Access' label. Most crawled pages returned only 'Connect wallet' with no usable content.
Warnings
- —No API documentation available — docs, pricing, and API pages all render only a 'Connect wallet' prompt with no further content.
- —No request or response schema is published; the exact purpose and expected input/output of /api/v1/cards/40/transactions is unknown.
- —The endpoint path suggests card-specific transaction data but no details confirm what 'card 40' refers to.
- —The provider site lists many diverse API categories but none specifically mention a 'cards' endpoint, raising questions about this resource's purpose.
Citations
- —Endpoint returns HTTP 402 with x402 challenge requiring 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/cards/40/transactions
- —USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/cards/40/transactions
- —Provider advertises $0.02 per request, no API keys, no rate limits, instant access on Base networkhttps://lowpaymentfee.com
- —Docs, pricing, and API pages return only 'Connect wallet' with no further documentationhttps://lowpaymentfee.com/docs