Pay-per-call tax returns API for 2026, settled in USDC on Base via x402.
What it does
This endpoint at lowpaymentfee.com provides a tax returns API for the year 2026, accessible via the x402 payment protocol. It accepts POST requests and charges $0.02 per call in USDC on the Base network. Payment is handled inline via the X-PAYMENT header — no API keys, accounts, or rate limits are required.
The endpoint is part of a broader platform (lowpaymentfee.com) that offers dozens of pay-per-call APIs spanning data analytics, AI/ML inference, finance/Web3 data, and infrastructure utilities, all at a uniform $0.02/request price point. However, the specific endpoint listed here (`/api/v1/tax/returns/2026`) is not explicitly mentioned on the provider's landing page among the advertised API categories. Its exact input schema and response format are undocumented — the only confirmed details come from the x402 challenge: it accepts POST, returns application/json, and costs up to 20,000 base units of USDC (i.e., $0.02 given USDC's 6 decimals).
Because there is no OpenAPI spec, no request/response examples, and no dedicated documentation page for this specific endpoint (the /docs, /pricing, and /README pages all returned only a wallet-connect prompt with no substantive content), the actual functionality and data returned by this endpoint remain unclear. Prospective callers should be aware that the "tax returns 2026" framing is unverified and the endpoint may return placeholder or generic data.
Capabilities
Use cases
- —Retrieving tax return data for the year 2026 via a single paid API call
- —Integrating pay-per-call tax data into automated financial workflows
- —Agent-driven tax document retrieval without pre-registration
Fit
Best for
- —Developers needing on-demand tax data without API key management
- —AI agents that can settle USDC payments on Base
- —Prototyping x402 payment flows with a low-cost endpoint
Not for
- —Production tax filing or compliance — endpoint functionality is unverified
- —Users who need detailed documentation or guaranteed SLAs before integration
- —Anyone without a Base-compatible USDC wallet
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/tax/returns/2026 \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402-payment-token>" \
-d '{}'Endpoint
Quality
The endpoint is live (returns a valid x402 402 challenge) and pricing is clear ($0.02 USDC on Base), but there is no documentation, no OpenAPI schema, no request/response examples, and the specific /tax/returns/2026 path is not listed among the provider's advertised APIs. Functionality is essentially unverified.
Warnings
- —The /api/v1/tax/returns/2026 endpoint is not listed among the provider's advertised APIs on the landing page — its actual functionality is unknown.
- —No documentation exists: /docs, /pricing, and /README pages all return only a wallet-connect prompt with no content.
- —No OpenAPI spec or request/response schema is available; input format must be guessed.
- —'Tax returns 2026' is a future tax year — the data returned may be placeholder or synthetic.
Citations
- —The endpoint returns a valid x402 challenge with maxAmountRequired of 20000 base units of USDC on Basehttps://lowpaymentfee.com/api/v1/tax/returns/2026
- —The platform advertises $0.02/request pricing with no API keys, no rate limits, and instant access on the Base networkhttps://lowpaymentfee.com
- —The USDC asset contract on Base is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913https://lowpaymentfee.com/api/v1/tax/returns/2026
- —The /api/v1/tax/returns/2026 path is not listed among the provider's advertised API categorieshttps://lowpaymentfee.com