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Bitcoin Fee Forecast & Transaction Cost Estimator
x402
Bitcoin Fee Forecast & Transaction Cost Estimator is a paid API for AI agents from finanz.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).
Returns current Bitcoin mempool fee rates by confirmation target and estimates the total fee in satoshis for a described transaction based on its virtual size.
Price / call$0.004
Success—
StatusUnknown
How this service works
Returns the current fee rates for the usual confirmation targets together with the state of the mempool behind them, and then does the part that is usually missing: it estimates the virtual size of the transaction you describe and computes the resulting total fee in satoshis for each target.
Output
Returns a list of confirmation targets (e.g. next block, 3 blocks, 6 blocks) each with the current fee rate in sat/vB, the estimated virtual size of the described transaction in vBytes, the computed total fee in satoshis, and mempool state information (e.g. pending transactions, congestion level).
Example use cases
Wallet fee suggestion for user withdrawal
“I'm sending Bitcoin from my wallet — it has 1 input and 1 P2WPKH output. What's the cheapest fee in satoshis to get confirmed within 6 blocks right now, and what does the mempool look like?”
Exchange batch payout fee planning
“We're doing a batch Bitcoin payout with 10 inputs and 25 outputs using native SegWit. Estimate the total fee in satoshis for next-block, 3-block, and 6-block confirmation targets so we can pick the most cost-effective option.”
DCA bot pre-send fee check
“Before my Bitcoin DCA bot sends its weekly transaction (1 input, 1 output, SegWit), can you check current mempool conditions and tell me exactly how many satoshis the fee will be for a 3-block confirmation?”
Technical details
Endpoint
POSThttps://finanz.halowerk.com/v1/bitcoin-fee-forecastWhen to prefer
Choose this endpoint when you need both a live mempool fee rate AND a transaction-specific total fee estimate in a single call — it eliminates the two-step process of fetching rates and separately calculating vsize. Ideal for wallets, DCA bots, exchanges, or any agent that needs to present precise fee costs to a user before broadcasting a Bitcoin transaction.
Side effects
- Invalid or missing transaction description causes 400 error
- Mempool data temporarily unavailable from upstream node
- Unreachable confirmation target (too low or too high) returns an error
- Malformed input counts or transaction type enum returns validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputs | integer | Number of inputs your transaction spends. This is what drives the cost. |
| outputs | integer | Number of outputs, usually recipient plus change. |
| input_type | string | |
| output_type | string |
Tags
x402
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