Pay-per-call USD/SEK forex exchange rate via x402 on Base (USDC).
What it does
This endpoint provides the current USD/SEK foreign exchange rate through a simple POST request, paid per call using the x402 protocol. It is hosted on lowpaymentfee.com, a platform offering a variety of pay-per-request APIs spanning finance, AI, data analytics, and utility services.
The endpoint accepts x402 payments on the Base network using USDC (contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913). The maximum amount required per request is 20,000 base units of USDC, which equals $0.02 (USDC uses 6 decimals). No API keys or rate limits are advertised — access is gated solely by the x402 payment header. The response MIME type is application/json.
Documentation beyond the landing page is extremely sparse. The /docs, /pricing, /api, and /README pages all returned only a "Connect wallet" prompt with no additional technical content. There is no OpenAPI spec, no request/response schema documentation, and no example payloads available. The endpoint is confirmed live (returns a proper 402 challenge), but the actual response format for a successful paid request is unknown and must be inferred from the endpoint path (likely a JSON object containing the USD/SEK exchange rate).
Capabilities
Use cases
- —Fetching the current USD/SEK exchange rate for financial applications
- —Automating currency conversion calculations in trading bots
- —Embedding live forex data into dashboards or reports
- —Agent-driven forex lookups without API key management
Fit
Best for
- —Developers needing on-demand USD/SEK rates without subscription commitments
- —AI agents that need programmatic forex data with crypto-native payment
- —Low-volume or sporadic forex rate lookups at $0.02 per call
Not for
- —High-frequency trading requiring sub-second latency and bulk rate plans
- —Users who need historical forex time-series data (no evidence this is supported)
- —Teams requiring detailed API documentation and SLA guarantees
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/forex/USDSEK/rate \
-H "X-PAYMENT: <x402-payment-header>" \
-H "Content-Type: application/json"Endpoint
Quality
The endpoint is confirmed live with a valid x402 402 challenge and clear pricing ($0.02/request in USDC on Base). However, there is no OpenAPI spec, no request/response schema, and all documentation pages are empty stubs showing only 'Connect wallet'. The actual response format is entirely unknown.
Warnings
- —No API documentation available — /docs, /pricing, /api, and /README pages are all empty stubs
- —No OpenAPI or JSON schema for request or response bodies
- —Response format for a successful paid call is unknown and cannot be verified
- —The platform lists many diverse API categories (AI, analytics, finance, utilities) all at the same price, which may indicate placeholder or thin implementations
Citations
- —The endpoint returns a 402 challenge with maxAmountRequired of 20000 base units of USDC on Base networkhttps://lowpaymentfee.com/api/v1/forex/USDSEK/rate
- —Platform pricing is $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/forex/USDSEK/rate
- —Documentation pages (/docs, /pricing, /api, /README) contain only 'Connect wallet' with no technical contenthttps://lowpaymentfee.com/docs