Pay-per-call OpenAI API key access via x402 on Base for $0.02 USDC per request.
What it does
This x402 endpoint at lowpaymentfee.com provides on-demand access to an OpenAI API key. When you pay the per-request fee, the endpoint returns a usable OpenAI API key that you can use for downstream calls. The payment is settled in USDC on the Base network using the x402 exact-payment scheme.
The endpoint charges a maximum of 20,000 base units of USDC (6 decimals), which equals $0.02 per request. There are no API keys, subscriptions, or rate limits required on the lowpaymentfee.com side — you simply attach an X-PAYMENT header with a valid x402 payment proof and receive the key in the JSON response. The site advertises a broader suite of APIs across data/analytics, AI/ML, finance/Web3, and utility categories, all at the same $0.02 per-request price point.
The endpoint is live and returns a proper x402 challenge (HTTP 402) when called without payment. It accepts POST requests and returns application/json. The payment is directed to address 0x1A2B13E97f5F837C8F9FA1F95a1484B7C70d85F3 using USDC contract 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base.
Capabilities
Use cases
- —Agents that need temporary OpenAI API access without managing their own key
- —One-off LLM calls where maintaining a subscription is unnecessary
- —Programmatic access to OpenAI capabilities paid per-call in crypto
- —Serverless or ephemeral workflows that need short-lived API credentials
Fit
Best for
- —AI agents needing on-demand OpenAI access without pre-registration
- —Developers who want to pay per-call in USDC on Base
- —Crypto-native applications that avoid traditional billing
Not for
- —High-volume production workloads where a direct OpenAI subscription is cheaper
- —Users who need guaranteed long-lived API keys with SLA guarantees
- —Applications requiring non-USDC or non-Base payment methods
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/integrations/openai/key \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>"Example
Request
{
"url": "https://lowpaymentfee.com/api/v1/integrations/openai/key",
"method": "POST",
"headers": {
"X-PAYMENT": "<x402_payment_proof_for_20000_USDC_base_units>",
"Content-Type": "application/json"
}
}Endpoint
Quality
The endpoint is live and returns a valid x402 challenge with clear pricing. However, there is no OpenAPI schema, no documentation of the response format, and no examples of what the returned payload looks like. The crawled pages beyond the homepage were empty (just 'Connect wallet'). The exact nature of the returned key (ephemeral vs. persistent, usage limits) is unknown.
Warnings
- —No documentation of the response schema — unclear what fields are returned beyond presumably an OpenAI API key
- —No OpenAPI or machine-readable schema available
- —Unclear whether the returned OpenAI key is ephemeral, rate-limited, or shared
- —The broader site lists many endpoints but detailed docs pages returned no content
- —Security consideration: using a third-party-provided API key means the provider can see all traffic routed through that key
Citations
- —Endpoint returns HTTP 402 with x402 challenge requiring 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/integrations/openai/key
- —USDC contract address is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Base networkhttps://lowpaymentfee.com/api/v1/integrations/openai/key
- —All APIs priced at $0.02 per request with no API keys, no rate limits, and instant accesshttps://lowpaymentfee.com