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Satoshi API - Bitcoin Fee Window Watch
x402
Satoshi API - Bitcoin Fee Window Watch is a paid API for AI agents from bitcoinsapi.com, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).
Starts a fee-window watch that monitors Bitcoin mempool fees and alerts when fees drop below (or meet) a specified sat/vB threshold within a defined time window
Price / call$0.1
Success—
StatusUnknown
How this service works
Know when to send Bitcoin and when to wait. Satoshi API gives apps and AI agents live fee recommendations, mempool context, and cost estimates. Free, open source.
Output
Returns a JSON object with a human-readable briefing string summarizing the watch, a watch object confirming the condition and threshold, poll instructions for the agent to check status (free after the paid watch start), an agent_action object with next steps, and status information. The response also echoes back the x402 price paid ($0.10).
Example use cases
Delay transaction until fees are cheap
“I need to send some Bitcoin but fees are high right now — set a watch for the next 8 hours and alert me when fees go below 8 sat/vB so I can send without overpaying.”
Automated DCA bot fee gating
“My Bitcoin DCA bot is about to broadcast a transaction — start a fee-window watch labeled 'dca-weekly' and hold until fees drop below 6 sat/vB within the next 12 hours.”
Time a large on-chain payment
“I'm moving a significant amount of Bitcoin and want to minimize fees — watch the mempool for the next 24 hours and tell me when fees fall below 4 sat/vB so it's safe to send.”
Technical details
Endpoint
POSThttps://bitcoinsapi.com/api/v1/watch/fee-windowWhen to prefer
Use this endpoint when an agent or app needs to defer a Bitcoin transaction until fees are favorable, rather than polling repeatedly on its own. It is ideal when you want a managed fee-watch with a briefing and poll-back pattern rather than fetching instantaneous fee data. Prefer this over a simple fee-lookup endpoint when the goal is conditional triggering — wait until fees are below X — rather than just knowing the current fee level.
Side effects
- Missing or invalid threshold_sat_vb — returns validation error
- Invalid condition value — watch cannot be created
- window_hours out of acceptable range — rejected
- Payment not included or insufficient — x402 payment required response
- Network or mempool data unavailable — service may return error or degraded briefing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| label | string | |
| condition | string | |
| window_hours | integer | |
| threshold_sat_vb | number | Fee threshold in sat/vB. |
Output
Schema · Response
{
"type": "json",
"schema": {
"type": "object",
"required": [
"briefing",
"watch",
"poll"
],
"properties": {
"poll": {
"type": "object"
},
"watch": {
"type": "object"
},
"status": {
"type": "object"
},
"briefing": {
"type": "string"
},
"agent_action": {
"type": "object"
}
}
},
"example": {
"poll": {
"method": "GET",
"payment": "free_poll_after_paid_start"
},
"watch": {
"condition": "below",
"threshold_sat_vb": 5
},
"briefing": "Bitcoin fee-window watch",
"x402_price_usd": "$0.10"
},
"mimeType": "application/json"
}Tags
x402
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