@otcdex/sdk

TypeScript client for the OTC escrow marketplace Solana program.

npm i @otcdex/sdk @solana/web3.js

Three things to know

1. maxPricePerToken is an all-in bound — it includes the buyer-side protocol fee. Passing a listing's raw price always reverts. Use quoteFill().
2. All money is bigint. A u64 of 6-decimal quote units exceeds Number.MAX_SAFE_INTEGER around 9 billion units.
3. Reads should come from the indexer API, not getProgramAccounts — public RPCs throttle it. OtcClient is for spot checks and tests.

Quote and fill

import { quoteFill, fillListing, OtcClient } from '@otcdex/sdk';

const client = new OtcClient(connection);
const listing = await client.getListing(listingAddress);
const { feeBps } = (await client.getConfig())!;

// Pure math, no RPC. 50 = 0.5% slippage headroom.
const q = quoteFill(listing!, amount, feeBps, 50);
// q.buyerPays, q.sellerReceives, q.protocolFee, q.maxPricePerToken

const ix = fillListing({
  buyer, listing: listing!.address,
  tokenMint: listing!.tokenMint, quoteMint: listing!.quoteMint,
  tokenProgram: listing!.tokenProgram, quoteTokenProgram: listing!.quoteProgram,
  buyerTokenAccount, buyerQuoteAccount, sellerQuoteAccount,
  amount, maxPricePerToken: q.maxPricePerToken,
});

Sweep several listings

import { buildBasket, planSweep } from '@otcdex/sdk';

const plan = planSweep(listings, targetAmount, feeBps, 50);
const { transactions, dropped } = await buildBasket(connection, ctx, plan.legs);
// `dropped` legs did NOT execute - surface them to the user.

Batches are capped at 10 fills per transaction. The binding limit is Solana's 64-account-lock budget, not transaction size or compute — measured, see basket.ts.

Also exported

createListing, updatePrice, cancelListing, admin instructions, decodeListing / decodeConfig, parseProgramEvents (rejects log lines forged by other programs), and all PDA helpers.

Docs

Security writeup · Frontend guide