# Crest Mempool State

> Crest Mempool State is a paid API for AI agents from data.crestsystems.ai, paid per call via x402, $0.002/call, status down (last checked 2026-09-15).

Returns current Bitcoin and Base blockchain mempool state including pending transaction counts and Bitcoin fee histogram

## Facts

- Endpoint: GET https://data.crestsystems.ai/data/mempool
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/data-crestsystems-ai-34637a69
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_apcmYx0qYdEKSirf14QiF

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 data-crestsystems-ai-34637a69
```

Example prompt: What's the current state of the Bitcoin mempool — how many transactions are pending and what does the fee histogram look like right now? Also check the Base chain pending TX count.

## When to prefer this

Use this endpoint when you need real-time mempool depth data for both Bitcoin and Base in a single call, particularly when deciding on transaction fee levels, estimating confirmation times, or monitoring network congestion. Prefer over on-chain RPC calls when you need a quick, no-setup fee histogram without running your own node.

## Known failure modes

- Upstream blockchain node unavailability may return 503 or empty data
- Stale data if mempool indexer is lagging behind chain tip
- Payment failure (402) if x402 USDC payment not attached or insufficient
- Rate limiting if called too frequently without valid payment

## How this service works

Crest · mempool — Fetch current mempool state across chains. Returns Bitcoin pending transaction count, fee histogram, and Base pending transaction count.

## Output

Returns current mempool snapshot including Bitcoin pending transaction count, a fee histogram (showing fee rate distribution across pending transactions), and Base chain pending transaction count — useful for estimating confirmation times and appropriate fee levels.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {}
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/data-crestsystems-ai-34637a69/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from data.crestsystems.ai](https://www.zero.xyz/host/data.crestsystems.ai/llms.txt)