API

JSON over HTTPS. Keys are issued by an admin.

Getting started

1Create an account
2Request access from your account page
3Once approved, create your secret key

curl https://api.fmze.dev/v1/stats \
  -H "X-API-Key: fmze_your_key"

Conventions

Base URL: https://api.fmze.dev/v1
Auth: X-API-Key header or Authorization: Bearer
Amounts: Integers in litoshis (1 LTC = 100000000)
Pages: ?page= returns { items, page, pageSize, total }
Errors: { "error": "..." } with a 4xx or 5xx status
Rate limits: Per key, per minute. Check X-RateLimit-Remaining.

Permissions

explorer: Read blocks, transactions, addresses and network stats
broadcast: Broadcast signed raw transactions
wallet:read: Read wallet balance, addresses and transactions
wallet:receive: Create new receiving addresses
wallet:send: Send LTC from the wallet

Network

GET/statsexplorer

Height, hashrate, difficulty, supply, mempool, fees, price, difficulty adjustment and halving.

GET/feesexplorer

Recommended fee rates in lit/vB to confirm within about 5 minutes (fast), 15 minutes (medium) and an hour (slow), and the minimum nodes relay.

GET/priceexplorer

LTC/USD and the 24 hour change.

GET/difficultyexplorer

Progress to the next difficulty adjustment and the estimated change.

GET/halvingexplorer

Next halving height, blocks left and estimated date.

GET/mining/pools?period=1dexplorer

Blocks found per pool. period is 1d or 1w.

GET/search?q={query}explorer

Finds a block height, block hash, txid or address. Returns { type, id }.

Blocks

GET/blocks?page={n}explorer

Latest blocks, 25 per page.

GET/blocks/tipexplorer

Height, hash and time of the latest block.

GET/blocks/{height|hash}?page={n}explorer

A block with 25 of its transactions per page.

GET/blocks/{height|hash}/txidsexplorer

Every transaction ID in the block.

GET/blocks/{height|hash}/hexexplorer

The raw block.

Transactions

GET/tx/{txid}explorer

Inputs with values, outputs with spent status, fee and confirmations.

GET/tx/{txid}/statusexplorer

Confirmed or not, confirmations and block. Cheap to poll.

GET/tx/{txid}/hexexplorer

The raw transaction.

POST/tx/decodeexplorer

Decodes a raw transaction without sending it.

{ "hex": "0200000001..." }

POST/tx/broadcastbroadcast

Sends a signed transaction. Returns { txid }.

{ "hex": "0200000001..." }

Mempool

GET/mempoolexplorer

Size, total fees, fee rate buckets, the block the node would mine next and the latest transactions.

GET/mempool/txidsexplorer

Every transaction ID waiting in the mempool.

Addresses

GET/address/{address}?page={n}explorer

Balance, totals and history with the change per transaction.

GET/address/{address}/utxosexplorer

Unspent outputs.

GET/address/{address}/validateexplorer

Whether the address is valid, and its type.

POST/addresses/balancesexplorer

Balances for up to 100 addresses.

{ "addresses": ["ltc1q...", "M8T1..."] }

Address watches

GET/watchesexplorer

Addresses this key is watching.

POST/watchesexplorer

Watch an address. Up to 1,000 per key.

{ "address": "ltc1q...", "label": "order-1042" }

DELETE/watches/{id}explorer

Stop watching.

Wallet

GET/walletwallet:read

Spendable, pending and immature balance.

GET/wallet/addresses?page={n}wallet:read

Receiving addresses and what each has received.

POST/wallet/addresseswallet:receive

New receiving address. type is bech32 (default), mweb, p2sh-segwit or legacy.

{ "label": "order-1042", "type": "bech32" }

GET/wallet/transactions?page={n}wallet:read

Wallet transactions, newest first.

GET/wallet/transactions/{txid}wallet:read

One wallet transaction.

GET/wallet/utxoswallet:read

Unspent outputs in the wallet.

POST/wallet/send/estimatewallet:send

The fee a send would pay, without sending. Same body as /wallet/send.

POST/wallet/sendwallet:send

Pays one or more addresses in one transaction. Use an Idempotency-Key header so a retry never pays twice.

{
  "to": [{ "address": "ltc1q...", "amount": 150000000 }],
  "subtractFee": false,
  "feeRate": 10,
  "comment": "payout 77"
}

Webhooks

address.transaction: A watched address sends or receives
wallet.transaction: The key's linked wallet sends or receives
Sent at: 0, 1 and 6 confirmations
Signature: X-Fmze-Signature: HMAC-SHA256 of {X-Fmze-Timestamp}.{body}
Retries: Up to 8 times over about 2 hours

{
  "event": "address.transaction",
  "address": "ltc1q...",
  "label": "order-1042",
  "txid": "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b",
  "amount": 150000000,
  "confirmations": 1,
  "blockHeight": 3104233
}

import { createHmac, timingSafeEqual } from 'node:crypto';

export function verifyWebhook(rawBody, headers, secret) {
  const expected = 'sha256=' + createHmac('sha256', secret)
    .update(headers['x-fmze-timestamp'] + '.' + rawBody)
    .digest('hex');
  const given = headers['x-fmze-signature'] ?? '';
  return given.length === expected.length &&
    timingSafeEqual(Buffer.from(given), Buffer.from(expected));
}