Over the Counter Desk

Digital Asset Exchange & Custodial Trading

The Challenges

The platform was built for one market, Kyrgyzstan, so it had to work with the local currency and the local banking system rather than a generic international setup.
Customers hold both money and crypto. Splitting those across two platforms means losing them at the point where they move between the two.
Fiat had to enter and leave through banks, in KGS and USD, by transfer and by card.
Customers arrive holding different assets on different chains. Supporting only one network means turning most of them away.
The platform holds customer funds. Transaction signing and verification are the platform's responsibility, and a mistake is a loss of real money.
Identity checks and daily trading limits are not optional in this business, and doing them by hand does not scale.
Customers want to trade with each other as well as with the platform.
Smart contracts cannot be corrected after deployment, so errors are permanent and expensive.
Deposits, swaps, P2P trading, withdrawals and compliance all grow at different rates and cannot be tied to one another's capacity.
The build had to move quickly.

Built the platform as a custodial exchange holding one balance per customer, so fiat and crypto sit in the same account and moving between them is an internal operation.
Opened fiat deposits by bank transfer in KGS and USD, holding the funds and converting them into USDT.
Opened crypto deposits for USDT, BTC, SOL, BNB, ETH and TRX across BEP20, TRC20, ERC20 and SOL, so customers arrive with what they already hold.
Added OTC swapping against the custodial balance, so a customer changes one asset for another instantly without going outside the platform.
Added a P2P module for customers to buy and sell directly with each other.
Opened withdrawals both ways - fiat to a bank account or card, crypto to any supported network.
Integrated Identomat for identity verification, and wired KYC status directly to automatic daily limits on deposits, withdrawals and OTC trades.
Built on a microservices architecture on Azure, so each part of the platform scales on its own demand.
Handled transaction verification and signing through Alchemy RPC.
Built, deployed and tested every smart contract on testnets mirroring mainnet - Ethereum Remix, Tron Remix, Solana CLI - before anything touched customer funds.
Used AI-assisted coding tools during development to shorten delivery.

Local customers move money in and out in their own currency through their own bank. Without this the platform has no market; with it, it is usable by ordinary customers rather than only crypto-native ones.
Money and crypto sit in one balance, so the customer has no reason to open an account somewhere else to make a conversion, and the platform keeps the volume it would otherwise hand to a competitor.
Three routes to trade - OTC swap, P2P and fiat conversion - mean the platform earns from a customer whichever way that customer prefers to work.
Compliance runs itself. KYC status and daily limits are enforced automatically, so the platform can take on more customers without adding people to check them, and limit breaches are prevented rather than found afterwards.
Six assets across four networks covers what customers already hold, so onboarding does not start with asking them to move funds elsewhere first.
Testing every contract against a mirror of the live environment before release protects customer funds, which in this business is the whole basis of trust.

Backend & frontend: Node.js, TypeScript, NestJS, GraphQL, TypeORM, PostgreSQL, ReactJS
Architecture & cloud: microservices on Microsoft Azure
Blockchain libraries: Web3.js, Ethers.js, TronWeb, @solana/web3.js
Blockchain infrastructure: Alchemy RPC for transaction verification and signing
Smart contracts: built, deployed and tested on testnets mirroring mainnet using Ethereum Remix, Tron Remix, Solana CLI
Identity / KYC: Identomat
Development: AI-assisted coding tools

Node.jsTypeScriptNestJSGraphQLPostgreSQLReactJSAzureWeb3.jsEthers.jsSolana