Slipstream API integration guide

Slipstream takes a signed raw transaction over HTTPS, checks it against the avonpool betanet node and a fee rule, and broadcasts it so the pool mines it. Base URL: https://slipstream.beta.avonpool.xyz. No API key, JSON responses, CORS open to any origin.

Endpoints

All paths are relative to https://slipstream.beta.avonpool.xyz. Plain HTTP redirects to HTTPS with a 301.

Submitting a transaction

Send the fully signed transaction as hex in one POST. The service runs testmempoolaccept first, so nothing is broadcast unless the node and the fee rule both accept it. Two body formats are accepted:

• Content-Type: text/plain (or none): the body is the hex string itself.
• Content-Type: application/json: {"hex": "0200..."}. A bare JSON string or {"tx": "..."} also works.

curl -s -X POST --data-binary "$RAW_TX_HEX" \
  https://slipstream.beta.avonpool.xyz/api/tx

const BASE = 'https://slipstream.beta.avonpool.xyz';

async function submitTx(hex) {
  const res = await fetch(`${BASE}/api/tx`, {
    method: 'POST',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ hex }),
  });
  const body = await res.json();
  if (res.status === 429) throw new Error('rate-limited: retry next minute');
  if (res.status >= 500) throw new Error(`slipstream unavailable: ${body.reject_reason ?? res.status}`);
  return body; // check body.accepted, then body.reject_reason
}

An accepted response carries the stored record, abridged here (the full field list is under Tracking a transaction):

{
  "accepted": true,
  "txid": "3f1c...",
  "wtxid": "9a2e...",
  "status": "pending",
  "vsize": 141,
  "weight": 561,
  "fee_sats": 282,
  "fee_rate": 2,
  "required_fee_rate": 1,
  "submitted_height": 970802
}

Submitting the same transaction again is safe. It returns accepted: true with already_tracked: true and the current record, instead of an error.

Responses and reject reasons

Always read accepted from the body: a rejection by the node or the fee rule comes back as HTTP 200 with accepted: false. Only malformed input, rate limiting and outages use other status codes.

Tracking a transaction

Poll GET /api/tx/{txid} until tx.status is confirmed or dropped. The service rechecks every transaction on each new block template, so polling every 30–60 seconds is enough.

The usual path is pending → in_template → mined → confirmed. Two moves go backwards: a block that is orphaned returns its transaction to pending, and a transaction that leaves the mempool is resent automatically, ending in pending or dropped. A dropped transaction can be submitted again once it is valid.

curl -s https://slipstream.beta.avonpool.xyz/api/tx/$TXID

The tx object has these fields: txid, wtxid, vsize, weight, fee_sats, fee_rate, required_fee_rate, submitted_at, submitted_height, submitter, status, status_reason, status_at, first_in_template_at, last_in_template_at, mined_block_hash, mined_height, mined_at, mined_by_pool, confirmations, confirmed_at, resubmissions. Times are Unix seconds; rates are sat/vB. events is the history as [{ts, event, detail}], oldest first.

GET /api/txs?status=in_template&limit=100 lists recent transactions across all submitters, without submitter.

Fees

Build the transaction at or above required_rate from GET /api/fees, or it is refused with fee-rate-too-low. The required rate is the higher of the pool's floor (1 sat/vB) and the current mineable rate. The mineable rate equals the floor while the block template has room, and becomes the cheapest included transaction's rate once the template is full.

curl -s https://slipstream.beta.avonpool.xyz/api/fees

{"min_submission_rate":1,"mineable_rate":1,"required_rate":1,"template_height":970802,"template_weight":3766,"updated_at":1790866502}

The fee rate is checked as fee in sats divided by virtual size, so read it just before signing and add a margin if blocks are filling up.

info.json

GET /info.json describes the pool for pool directories and is cached for 60 seconds. Mode, fee, coinbase tag and addresses are read from the running pool, so they always match what the coinbase pays. The same document is served at https://pool.beta.avonpool.xyz/info.json.

{
  "name": "avonpool_beta",
  "operator": "avonpool",
  "chain": "betanet",
  "mode": "solo",
  "fee_bps": 100,
  "coinbase_tag": "/avonpool/",
  "stratum_url": "stratum+tcp://pool.beta.avonpool.xyz:3334",
  "dashboard_url": "https://pool.beta.avonpool.xyz",
  "status_url": "https://pool.beta.avonpool.xyz/api/status",
  "slipstream_url": "https://slipstream.beta.avonpool.xyz",
  "operator_address": "bc1qljvzxk0tp6qtrunt590z5rtdhs8jhkkn4ny4rm",
  "pool_btc_address": null,
  "payout": "The stratum username is your BTC address; each block's coinbase pays the miner who found it.",
  "software": "simplepool",
  "version": "0.1.0",
  "logo": null,
  "contact": "pool@ecash.com"
}

fee_bps is in basis points (100 = 1%). status_url returns live pool statistics (hashrate, workers, blocks).

Limits and caveats

• Standard transactions only. The betanet node reports its chain as main, where Bitcoin Core does not allow non-standard transactions. A non-standard output is refused with scriptpubkey. BIP300 deposits are standard and are accepted.
• Not exclusive to avonpool. An accepted transaction is relayed like any other, so another pool may mine it first. mined_by_pool says which.
• Rate limit: 30 submissions per minute per client IP, counted in fixed one-minute windows. Reads are limited by nginx with a burst of 20.
• Size: at most 1 MB of transaction per request.
• Your IP is stored. Each submission records the client IP as submitter, and GET /api/tx/{txid} returns it to anyone who knows the txid.
• Health check: before a batch of submissions, GET /healthz returns 503 if the pool cannot build templates, and submissions may then fail with node-unavailable.