Module mempool 

Native mempool.space REST client (provenance-upgrade Phase 3). Concrete solid_pod_rs::mrc20::MempoolLookup + the verify-side solid_pod_rs::provenance::BlockAnchorer. Server-side only (builds a reqwest::Client); wasm consumers implement the trait over fetch. Native mempool.space REST client — the read-side of block-trail anchors.

[MempoolHttpClient] is the server-side concrete implementation of the pure solid_pod_rs::mrc20::MempoolLookup trait. It speaks the mempool.space-style REST API over the reqwest client the crate already pulls in for the CORS proxy and webhook delivery:

Method	Path	Returns
GET	{base}/api/address/{addr}/utxo	Vec<Utxo>
GET	{base}/api/tx/{txid}	TxInfo

The wire shapes (status: {confirmed, block_height} nested objects) are deserialised into local *Wire structs and flattened into the crate’s transport-free [Utxo]/[TxInfo] value types, so the pure verification surface never learns the mempool.space schema.

wasm boundary

This module is native-only (it builds a reqwest::Client). It mirrors the JSS verifyMrc20Anchor mempool round-trip (mrc20.js:315-327, token.js:176-187) and is the production [MempoolLookup] the /pay/.deposit MRC20 path and /pay/.address derivation use. wasm consumers implement [MempoolLookup] over fetch instead and never compile this file.

Configuration

The base URL is read from JSS_PAY_MEMPOOL_URL (JSS mempoolUrl parity), defaulting to the testnet4 explorer https://mempool.space/testnet4. The reqwest json feature is not enabled crate-wide, so responses are read as text and parsed with serde_json (matching the proxy handler’s manual-parse style).

Structs

MempoolBlockAnchorer

A BlockAnchorer implementing both sides over a transport that can look up UTXOs (MempoolLookup) and broadcast transactions (MempoolBroadcast). Generic over that transport so a fixture drives it in tests and MempoolHttpClient drives it in production — without changing the logic.

MempoolHttpClient

A MempoolLookup backed by the mempool.space REST API over reqwest.

Constants

DEFAULT_MEMPOOL_URL

Default base URL — the mempool.space testnet4 explorer. Matches the JSS default (pay.js:243, mrc20.js:282).

MEMPOOL_URL_ENV

Environment variable selecting the mempool REST base URL (JSS parity).