# Bitcoin Mempool Size and Backlog

> Bitcoin Mempool Size and Backlog is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-01).

Returns the current Bitcoin mempool size and transaction backlog, including a payment receipt for the x402 micropayment.

## Facts

- Endpoint: POST https://twin.unykorn.org/btc-mempool?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/bitcoin-mempool-size-and-backlog-dec19269
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__ETzCOlMkYMqvyGl_d2LQ

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 bitcoin-mempool-size-and-backlog-dec19269 -d '<json body>'
```

Example prompt: How congested is the Bitcoin network right now? Give me the current mempool size and backlog so I can decide whether to send a transaction.

## When to prefer this

Choose this endpoint when you need a quick, low-cost snapshot of Bitcoin mempool congestion, especially in an agentic workflow that pays per-call via x402 micropayments. Prefer this over running your own Bitcoin node query when you want a hosted, no-setup solution for mempool monitoring or fee estimation heuristics.

## Known failure modes

- Network or upstream Bitcoin node unavailable — returns error or non-ok response
- Payment failure via x402 micropayment protocol — call may not proceed without valid payment
- Stale data if the upstream mempool source is lagging
- Malformed response if the Bitcoin node is syncing or unreachable

## How this service works

Bitcoin mempool size and backlog — Genesis402 / UnyKorn Operator Network

## Output

Returns a JSON object with 'ok' status, a type field ('btc-mempool'), the mempool data (size and backlog), a timestamp ('generated_at' in ISO 8601), and a payment receipt containing the transaction hash, USD amount charged, and a unique receipt ID.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "btc-mempool",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.002,
   "receipt_id": "g402-<16hex>"
  },
  "generated_at": "<iso8601>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/bitcoin-mempool-size-and-backlog-dec19269/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)