Check Filecoin (FIL) wallet balances via a pay-per-call x402 endpoint on Base.
What it does
This endpoint at lowpaymentfee.com returns Filecoin (FIL) wallet balance data, accessed via the x402 payment protocol. Each call costs $0.02 in USDC on the Base network — no API keys, no rate limits, and no subscriptions required. The caller simply includes an X-PAYMENT header with a valid x402 payment proof and receives a JSON response.
The endpoint is part of a broader suite of APIs offered by lowpaymentfee.com spanning data analytics, AI/ML inference, finance/Web3 data, and utility services — all priced uniformly at $0.02 per request. The specific endpoint `/api/v1/wallet/FIL/balance` sits in the Finance & Web3 category and is designed to return balance information for Filecoin wallets. Payment settles in USDC (contract 0x8335…2913) on Base using the "exact" x402 scheme, with a maximum amount of 20,000 base units (i.e., $0.02 given USDC's 6 decimals).
Documentation on the site is extremely sparse — the docs, pricing, and API pages all render only a "Connect wallet" prompt with no further technical detail. There is no OpenAPI spec, no request/response schema, and no usage examples available from the crawled material. The endpoint is confirmed live (returns a proper 402 challenge), but the actual request format (e.g., whether a wallet address is passed in the body or URL) and response schema are unknown.
Capabilities
Use cases
- —Querying the balance of a Filecoin wallet address programmatically
- —Integrating FIL balance checks into a portfolio tracker or dashboard
- —Automated monitoring of Filecoin wallet balances in agent workflows
Fit
Best for
- —Agents or apps needing on-demand FIL balance lookups without managing API keys
- —Developers who want pay-per-call crypto data without subscriptions
- —x402-native workflows settling micropayments on Base
Not for
- —Bulk or high-frequency balance polling where per-call fees add up quickly
- —Users who need detailed FIL transaction history or on-chain analytics beyond balance
Quick start
curl -X POST https://lowpaymentfee.com/api/v1/wallet/FIL/balance \
-H "Content-Type: application/json" \
-H "X-PAYMENT: <x402_payment_proof>" \
-d '{"address": "f1..."}'Example
Request
{
"address": "f1examplefilecoinaddress"
}Endpoint
Quality
The endpoint is confirmed live via a valid 402 challenge and pricing is clear ($0.02 USDC on Base). However, there is no OpenAPI spec, no documented request/response schema, no usage examples, and the docs pages are empty stubs. The request body format and response structure are entirely inferred.
Warnings
- —No OpenAPI or schema documentation available — request and response formats are unknown
- —Docs, pricing, and API pages on the site render only a 'Connect wallet' prompt with no technical content
- —Example request JSON is speculative; actual required fields are undocumented
- —The broader site lists many API categories but none have visible documentation
Citations
- —Endpoint returns a 402 challenge with x402Version 1, scheme 'exact', network 'base', maxAmountRequired 20000 USDChttps://lowpaymentfee.com/api/v1/wallet/FIL/balance
- —All APIs on the site are priced at $0.02 per request with no API keys, no rate limits, and instant access on Base networkhttps://lowpaymentfee.com
- —USDC asset contract is 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 on Basehttps://lowpaymentfee.com/api/v1/wallet/FIL/balance