@hashlock/sdk

TypeScript SDK for HashLock — institutional OTC trading with HTLC atomic settlement on Ethereum and Bitcoin.

📐 Architecture: how this SDK is layered and how it connects to the Hashlock Markets backend — docs/architecture/ARCHITECTURE.md (Русский).

Install

npm install @hashlock/sdk
# or
pnpm add @hashlock/sdk

Quick Start

import { HashLock } from '@hashlock/sdk';

const hl = new HashLock({
  endpoint: 'http://142.93.106.129/graphql',
  accessToken: 'your-jwt-token',
});

// Create an RFQ to sell 1 ETH for USDT
const rfq = await hl.createRFQ({
  baseToken: 'ETH',
  quoteToken: 'USDT',
  side: 'SELL',
  amount: '1.0',
});

console.log(`RFQ created: ${rfq.id}`);

Authentication

Get a JWT token by logging into the HashLock platform, then pass it to the SDK:

const hl = new HashLock({
  endpoint: 'http://142.93.106.129/graphql',
  accessToken: 'eyJhbGciOiJIUzI1NiIs...',
});

// Or update the token later
hl.setAccessToken('new-token');

RFQ Trading

Create an RFQ (Request for Quote)

const rfq = await hl.createRFQ({
  baseToken: 'BTC',
  quoteToken: 'USDT',
  side: 'BUY',
  amount: '0.5',
  expiresIn: 300, // 5 minutes
});

Respond with a Quote

const quote = await hl.submitQuote({
  rfqId: rfq.id,
  price: '68500.00',
  amount: '0.5',
});

Accept a Quote (creates a Trade)

const accepted = await hl.acceptQuote(quote.id);
// accepted.trade.id -> trade ready for settlement

List & Query

const { rfqs, total } = await hl.listRFQs({ status: 'ACTIVE', page: 1 });
const rfq = await hl.getRFQ('rfq-uuid');
const quotes = await hl.getQuotes('rfq-uuid');

Instant Settlement (Lane A)

Solvers (market makers running the instant-settlement flow) can commit to fronting the taker's asset immediately when their quote is accepted, and get reimbursed when the underlying trade settles. The whole surface is feature-flagged on the backend — when the flag is off, the SDK degrades gracefully (see Flag-off behaviour below).

Money fields: InstantFill.amountWei is the committed amount in the asset's smallest on-chain unit (wei / sats / MIST) as a decimal string covering the full uint256 range. Never convert it to a JS number (precision is lost above 2^53) — use BigInt(fill.amountWei).

Taker flow

The canonical instant path is: requestInstantFill succeeds first, then acceptQuote. The requestInstantFillAndAccept helper enforces this order inside the SDK and maps every failure mode to a typed result:

import { policyPresets } from '@hashlock-tech/sdk';

const res = await hl.requestInstantFillAndAccept(rfq.id, quote.id, {
  policy: policyPresets.instant, // optional preference (see Policy semantics)
});

switch (res.kind) {
  case 'instant':
    // Fill committed AND quote accepted — solver fronting is on its way.
    console.log('instant fill', res.fill.id, BigInt(res.fill.amountWei));
    break;
  case 'standard':
    // Instant path refused with a typed reason — the SDK already fell
    // back to a normal acceptQuote, the trade proceeds on the standard path.
    // res.reason: 'disabled' | 'lane_conflict' | 'already_requested'
    // res.lane is set for lane_conflict.
    console.log('standard path:', res.reason);
    break;
  case 'fill_orphaned':
    // requestInstantFill succeeded but acceptQuote failed — the fill is
    // committed server-side. Retry the ACCEPT ONLY (never re-request the
    // fill: instant fills are exactly-once per quote and would 409):
    const retry = await hl.retryAcceptAfterInstantFill(res.fill);
    break;
}

Decision table implemented by the helper:

requestInstantFill	acceptQuote	Result
OK	OK	{ kind: 'instant', fill, quote }
INSTANT_FILL_DISABLED	OK (fallback)	{ kind: 'standard', reason: 'disabled', quote }
lane conflict (extensions.lane)	OK (fallback)	{ kind: 'standard', reason: 'lane_conflict', lane, quote }
already requested (exactly-once)	OK (fallback)	{ kind: 'standard', reason: 'already_requested', quote }
any other error	— (not attempted)	thrown (auth/network/unknown errors are never swallowed)
OK	FAIL	{ kind: 'fill_orphaned', fill, error: InstantFillOrphanedError }

Takers can watch for the fronting payment (payload: InstantFillFrontedEvent — the fill id arrives as fillId):

const handle = hl.onInstantFillFronted((event) => {
  console.log('fronted!', event.fillId, event.frontTxHash);
});
// later: handle.unsubscribe();

Solver flow

Submit an instant-fill quote, then serve incoming fill requests:

// 1. Commit on the quote (solverVaultAddr is required with instantFill)
const quote = await hl.submitQuote({
  rfqId: rfq.id,
  price: '3450.00',
  amount: '10.0',
  instantFill: true,
  solverVaultAddr: '0xYourVault...',
});

// 2. Watch for accepted instant fills and front them. The subscription
//    payload is InstantFillRequestedEvent — fillId/quoteId/rfqId/state/
//    amountWei/createdAt (NOT the InstantFill mutation type).
//    serveInstantFills = subscribe(instantFillRequested) + auto markInstantFillFronted
const handle = hl.serveInstantFills(async (event) => {
  const txHash = await vault.front(event.quoteId, BigInt(event.amountWei));
  return txHash; // SDK calls markInstantFillFronted(event.fillId, txHash) for you
}, {
  onFronted: (fill) => console.log('fronted', fill.id),
  onError: (err, event) => console.error('fronting failed', event?.fillId, err),
});

// Or drive the two halves manually:
hl.onInstantFillRequested(async (event) => {
  const txHash = await vault.front(event.quoteId, BigInt(event.amountWei));
  await hl.markInstantFillFronted(event.fillId, txHash);
});

Subscriptions use the graphql-transport-ws protocol. Browsers and Node >= 22 work out of the box (global WebSocket); on Node 18/20 pass an implementation: new HashLock({ ..., webSocket: (await import('ws')).default }). Streams are scoped server-side by the authenticated user (instantFillRequested → the quote's maker, instantFillFronted → the taker).

Policy semantics — a preference, not a commitment

acceptQuote(quoteId, policy) takes an optional AgentPolicy ({ maxLatencyMs?, maxFeeBps?, minTrust? }). A policy is routing advice: it never causes the accept to fail. The SDK sanitizes it before sending — invalid fields are dropped, and if nothing valid remains the accept silently proceeds on the standard path with no policy at all.

Presets mirror the human speed slider 1:1 (single engine, two adapters):

Preset	Policy	Under the hood
policyPresets.instant	{ maxLatencyMs: 3000 }	Lane A/B fronting, 0–1 confs, wide spread
policyPresets.balanced	{ minTrust: 'med' }	Lane A, 2–3 confs (add your own maxFeeBps)
policyPresets.trustless	{ minTrust: 'max' }	Lane Z pure HTLC, full confs, tight spread

await hl.acceptQuote(quote.id, { ...policyPresets.balanced, maxFeeBps: 30 });

minTrust on the wire: the schema's AgentPolicyInput.minTrust is an Int (a 0–100 solver trust/reputation score), so the SDK converts a TrustLevel string before sending (TRUST_LEVEL_TO_SCORE). The backend guard is minTrust > solverReputation (reputation stubbed at 50 until the reputation oracle lands):

TrustLevel	Int sent	Effect against the 50 stub
'low'	0	never constrains
'med'	50	passes (50 > 50 is false) — Lane A allowed
'max'	100	unmet → steers to the trustless pure-HTLC path

You may also pass a raw 0–100 integer directly ({ minTrust: 75 } — floored and clamped). Strings never reach the wire: an unconverted 'med' would fail GraphQL Int coercion and reject the entire accept, which would break the "a policy can never fail the accept" guarantee.

Flag-off behaviour

The instant-settlement feature is gated by a backend flag. When it is off:

• requestInstantFill fails with INSTANT_FILL_DISABLED → requestInstantFillAndAccept returns { kind: 'standard', reason: 'disabled' } and the trade completes on the standard path. Nothing throws.
• submitQuote with instantFill: true is rejected by the backend; plain quotes are unaffected.
• policy on acceptQuote remains a no-op preference — accepted and ignored.

HTLC Settlement — ETH / ERC-20

After a trade is accepted, both parties lock assets in HTLC contracts.

Record an HTLC Lock (after on-chain tx)

// 1. Send ETH lock tx on-chain via ethers.js / viem
// 2. Record it in HashLock:
const result = await hl.fundHTLC({
  tradeId: 'trade-uuid',
  txHash: '0xabc123...',
  role: 'INITIATOR',
  timelock: Math.floor(Date.now() / 1000) + 3600,
  hashlock: '0xdef456...',
  chainType: 'evm',
});

Claim an HTLC (reveal preimage)

const claimed = await hl.claimHTLC({
  tradeId: 'trade-uuid',
  txHash: '0xclaim...',
  preimage: '0xsecret...',
  chainType: 'evm',
});

Refund (after timelock expiry)

const refunded = await hl.refundHTLC({
  tradeId: 'trade-uuid',
  txHash: '0xrefund...',
});

Check HTLC Status

const status = await hl.getHTLCStatus('trade-uuid');
console.log(status?.initiatorHTLC?.status);    // 'ACTIVE'
console.log(status?.counterpartyHTLC?.status);  // 'PENDING'

HTLC Settlement — Bitcoin

Bitcoin HTLCs use P2WSH scripts (no smart contract deployment needed).

Prepare a Bitcoin HTLC

const btcHtlc = await hl.prepareBitcoinHTLC({
  tradeId: 'trade-uuid',
  role: 'INITIATOR',
  senderPubKey: '02abc...',    // 33-byte compressed pubkey
  receiverPubKey: '03def...',
  timelock: Math.floor(Date.now() / 1000) + 7200,
  amountSats: '100000',        // 0.001 BTC
});

console.log(`Send BTC to: ${btcHtlc.htlcAddress}`);
// Fund this P2WSH address with your Bitcoin wallet

Claim a Bitcoin HTLC

// Build unsigned PSBT
const psbt = await hl.buildBitcoinClaimPSBT({
  tradeId: 'trade-uuid',
  htlcId: btcHtlc.htlcId,
  preimage: '0xsecret...',
  destinationPubKey: '02abc...',
  feeRate: 10, // sat/vB
});

// Sign with wallet (Xverse, Leather, UniSat, etc.)
const signedTx = await wallet.signPsbt(psbt.psbtBase64);

// Broadcast
const broadcast = await hl.broadcastBitcoinTx({
  tradeId: 'trade-uuid',
  txHex: signedTx,
});
console.log(`BTC claimed: ${broadcast.txid}`);

Cross-Chain Atomic Swap (ETH ↔ BTC)

// Alice (ETH side) locks USDT on Ethereum
await hl.fundHTLC({
  tradeId, txHash: evmTxHash, role: 'INITIATOR',
  hashlock, timelock: now + 7200, chainType: 'evm',
});

// Bob (BTC side) locks BTC on Bitcoin
const btc = await hl.prepareBitcoinHTLC({
  tradeId, role: 'COUNTERPARTY',
  senderPubKey: bobPub, receiverPubKey: alicePub,
  timelock: now + 3600, amountSats: '100000',
});
// Bob funds the P2WSH address, then:
await hl.fundHTLC({
  tradeId, txHash: btcFundingTxid, role: 'COUNTERPARTY',
  chainType: 'bitcoin', redeemScript: btc.redeemScript,
});

// Alice claims BTC (reveals preimage)
// Bob sees preimage on-chain → claims USDT on Ethereum
// Trade complete!

Error Handling

import { HashLockError, GraphQLError, AuthError, NetworkError } from '@hashlock/sdk';

try {
  await hl.getTrade('bad-id');
} catch (err) {
  if (err instanceof AuthError) {
    // Token expired — refresh and retry
  } else if (err instanceof GraphQLError) {
    console.error('API error:', err.errors);
  } else if (err instanceof NetworkError) {
    console.error('Network issue:', err.message);
  }
}

Configuration

const hl = new HashLock({
  endpoint: 'http://142.93.106.129/graphql', // mainnet
  accessToken: 'jwt-token',
  timeout: 30000,    // 30s (default)
  retries: 3,        // retry count (default)
});

Option	Type	Default	Description
endpoint	string	—	GraphQL API URL (required)
accessToken	string	—	JWT bearer token
timeout	number	30000	Request timeout (ms)
retries	number	3	Retry attempts for transient failures
fetch	typeof fetch	globalThis.fetch	Custom fetch implementation

Mainnet Contracts (Ethereum)

Contract	Address
HashedTimelockEther	0x0CEDC56b17d714dA044954EE26F38e90eC10434A
HashedTimelockEtherFee	0xfBAEA1423b5FBeCE89998da6820902fD8f159014
HashedTimelockERC20Fee	0x4B65490D140Bab3DB828C2386e21646Ed8c4D072

Development — vendored schema & drift guard

Every GraphQL operation string the SDK sends is validated in CI against a vendored copy of the authoritative trade-service SDL (test/fixtures/schema.graphql for queries/mutations, test/fixtures/schema.subscriptions.graphql for the graphql-ws subscription schema) — see src/__tests__/schema-validate.test.ts. The graphql package is a devDependency only; the published SDK keeps zero runtime dependencies.

When the backend schema changes, refresh the fixtures from the main repo's origin/main and re-run the tests:

git -C ../Cayman-Hashlock fetch origin
node scripts/vendor-schema.mjs ../Cayman-Hashlock   # optional: [path] [git-ref]
pnpm test

The fixture headers record the source path, git ref and commit SHA they were vendored from. Never edit the fixtures by hand.

License

MIT

About Hashlock Markets

Hashlock Markets (hashlock.markets) is operated by Hashlock Corp., a Delaware C-Corporation. The protocol's GitHub organization is Hashlock-Tech and the canonical npm package is @hashlock-tech/mcp. Hashlock Markets is not affiliated with Hashlock Pty Ltd (hashlock.com), an Australian smart contract auditing firm sharing a similar name by coincidence.

For more on the protocol: hashlock.markets · Documentation · llms.txt · MCP Registry · All Hashlock-Tech repos