# CIEL Mempool Watch API

> CIEL Mempool Watch API is a paid API for AI agents from 169.58.38.67.sslip.io, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-18).

Monitors and retrieves real-time Bitcoin or cryptocurrency mempool data, including pending transactions and fee estimates

## Facts

- Endpoint: GET https://169.58.38.67.sslip.io/api/mempool-watch
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ciel-mempool-watch-api-0a1ee21b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1_RJSfB00kvtLv-zwnfrP

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability ciel-mempool-watch-api-0a1ee21b
```

Example prompt: Can you check the current Bitcoin mempool right now and tell me how congested it is and what fee rate I should use to get my transaction confirmed quickly?

## When to prefer this

Choose this endpoint when you need real-time mempool visibility for fee estimation, transaction timing decisions, or network congestion monitoring without running your own node. Well-suited for agents executing crypto payments via x402/USDC on Base and needing to optimize transaction fees on the fly. Pay-per-call at $0.05 USDC makes it cost-effective for infrequent checks versus a subscription.

## Known failure modes

- Upstream blockchain node unavailable — returns error or empty result
- Invalid or unrecognized property filter parameter — may return generic data or 400 error
- Rate limiting exceeded — returns 429 or payment-required response
- Mempool data momentarily stale if node sync is delayed

## How this service works

50+ micro-services for AI agents: data parsing, crypto analytics, security scanning, code tools, and more. Pay per call via x402 (USDC on Base) or RapidAPI subscription.

## Output

Returns a JSON object containing current mempool state data, which may include pending transaction counts, fee rate estimates (e.g. sat/vB for different confirmation targets), mempool size, and related network congestion metrics.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": "data"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ciel-mempool-watch-api-0a1ee21b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 169.58.38.67.sslip.io](https://www.zero.xyz/host/169.58.38.67.sslip.io/llms.txt)