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fastapi.online — Bitcoin Network Fee Estimator
x402
fastapi.online — Bitcoin Network Fee Estimator is a paid API for AI agents from api.fastapi.online, paid per call via x402, $0.0005/call, status down (last checked 2026-10-31).
Returns current Bitcoin network transaction fee estimates (e.g. sat/vbyte rates) for different confirmation speed targets
Price / call$0.0005
Success—
StatusDown
How this service works
Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding & crypto utilities, date/time calculators, geo/coordinate math, math & finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.
Output
Returns current Bitcoin network fee estimates, typically including recommended fee rates in satoshis per virtual byte (sat/vbyte) for different confirmation speed tiers (e.g. next block, within a few blocks, economy/slow). Useful for setting appropriate miner fees before broadcasting a transaction.
Example use cases
Optimize BTC transaction fee before sending
“Before I send this Bitcoin transaction, what fee rate should I set in sats per vbyte to get it confirmed within the next block or two?”
Monitor Bitcoin mempool congestion
“Check the current Bitcoin network fees for me — I want to know if the mempool is congested right now and what the recommended fee tiers look like.”
Estimate BTC transfer cost for a payment app
“I'm building a Bitcoin payment flow — can you fetch the current fee estimates so I can show the user low, medium, and high priority fee options before they confirm the send?”
Technical details
Endpoint
POSThttps://api.fastapi.online/btc-fees?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need a quick, pay-per-call Bitcoin fee estimate without API key signup, especially in agent workflows that need real-time fee data to construct or validate BTC transactions. Prefer this over building your own mempool query when you want a simple HTTP call with crypto micropayment billing.
Side effects
- Service unavailable or self-hosted node offline — 5xx error
- Empty or malformed request body may cause 422 validation error
- Payment not included or insufficient — 402 Payment Required response
- Bitcoin node data stale or out of sync — fee estimates may lag real mempool conditions
- Rate limiting if payment not processed correctly
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object |
Tags
x402
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