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FastPath API - Bitcoin RBF Bump Plan
x402
FastPath API - Bitcoin RBF Bump Plan is a paid API for AI agents from api.nativebtc.org, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Returns a Replace-By-Fee (RBF) bump plan for an unconfirmed Bitcoin transaction, including current and target fee amounts needed to reach a desired confirmation block target.
Price / call$0.01
Success—
StatusUnknown
How this service works
FastPath translates Ethereum-style JSON-RPC requests into Bitcoin data, fee intelligence, mempool insight, and Core v31 package signals. Paid by x402.
Output
Returns a JSON object indicating the RBF bump method (e.g. rbf_signed_replacement), whether a bump is available, the current fee in satoshis, the target fee in satoshis for the desired block confirmation, the additional satoshis required, and whether the service signs or custodies funds (always false).
Example use cases
Speed up stuck mempool transaction
“My Bitcoin tx a3f1b2c4d5e6f7890123456789abcdef0123456789abcdef0123456789abcdef01 has been unconfirmed for 6 hours. Can you tell me how much I need to bump the fee to get it confirmed within 2 blocks?”
Fee bump cost check before signing
“Before I sign an RBF replacement for txid b7c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8, can you check how many additional satoshis I'd need to target confirmation in 6 blocks?”
Automated wallet fee escalation
“For transaction c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2, generate a bump plan targeting 1 block confirmation so I can decide whether it's worth accelerating the fee right now.”
Technical details
Endpoint
POSThttps://api.nativebtc.org/v1/template/bump-planWhen to prefer
Use this endpoint when you need to programmatically calculate how much additional fee is required to bump an unconfirmed Bitcoin transaction to a specific block confirmation target via Replace-By-Fee. Prefer this over generic fee estimators when you have a specific txid and need a tailored bump plan rather than a general fee rate. Ideal for wallets, payment processors, or agents managing time-sensitive Bitcoin transactions.
Side effects
- Invalid txid format (not 64 hex characters) returns a validation error
- Transaction not found in mempool or already confirmed may return available: false
- targetBlocks below minimum (1) returns a schema validation error
- Transaction not signaling RBF may return available: false
- Network congestion or node connectivity issues may cause delays or 5xx errors
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| txid | string | Bitcoin transaction ID as 64 lowercase or uppercase hex characters. |
| targetBlocks | number | Desired confirmation target in blocks. |
Output
Schema · Response
{
"type": "json",
"example": {
"method": "rbf_signed_replacement",
"success": true,
"available": true,
"targetFeeSats": 330,
"currentFeeSats": 220,
"additionalFeeSats": 110,
"signsOrCustodiesFunds": false
}
}Tags
x402
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