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Internet Money · Crypto financial services

One wallet interface across five blockchains

A multi-chain crypto platform where every chain hides behind one interface, with a tamper-evident audit trail underneath it. $10M+ moves through it monthly.

$10M+monthly transaction volume

At a glance

Duration
61 weeks
Team size
6 people
Engagement
New build
Project type
Web application
Industry
Fintech

The situation

The challenge

Multi-chain integration is a compatibility problem disguised as a feature. Every blockchain brings its own RPC protocol, transaction format, fee model, confirmation semantics and failure modes — and regulation on top of that demanded a complete, tamper-evident audit trail for every transaction and balance query.

What we did

We put an adapter behind every chain and one interface in front of them all, then built the audit trail as a hash chain rather than a log anyone could quietly edit.

The calls that mattered

  • A chain-agnostic wallet abstraction

    One adapter per chain — bitcoinjs-lib, ethers.js, web3.js, binance-chain-js — behind a single interface: getBalance, buildTransaction, signTransaction, broadcastTransaction, getTransactionStatus. Chain-specific data lives in opaque JSONB on a unified Transaction type, so adding a chain stopped being a refactor and became an adapter.

  • Price consensus rather than a price source

    CoinGecko, Binance WebSocket and Chainlink aggregated to a median, with outliers beyond 2% rejected and a circuit breaker per source. A single feed is a single point of failure that reports confidently right up until it is wrong.

  • An audit log that cannot be edited quietly

    Row-level hash chaining in PostgreSQL, so tampering breaks the chain and shows up. A separate compliance service generates regulatory reports from those records rather than from live tables.

What changed

monthly volume
$10M+monthly volume
uptime
99.99%uptime
to integrate a new chain
2-3 daysto integrate a new chain
price feed consensus latency
<200msprice feed consensus latency
  • $10M+ — across five chains
  • 99.99% — 52 minutes of downtime over 14 months
  • 2-3 days — down from weeks

Zero gaps and zero tamper events across security audits, 99.99% uptime over fourteen months, and a new chain integration measured in days instead of weeks.

Services used

  • Chain-agnostic wallet abstraction with five chain adapters
  • Real-time multi-source price pipeline with consensus and failover
  • Tamper-evident audit log and compliance reporting service
  • Operational runbooks and alerting

What we would do differently

Every project has one of these. Publishing it is the point — a case study with no regrets in it is marketing, not evidence.

In fintech, correctness is non-negotiable but so is resilience. A system that silently drops a transaction because a downstream RPC node timed out is worse than one that fails loudly. Every external call ended up with explicit retry logic, a timeout budget, a circuit breaker and an alert — built on the assumption of failure rather than the hope of success.

Services used

More work

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