Crypto infrastructure that settles correctly.

A customer sends USDC

250.00 USDC leaves the customer’s wallet for the deposit address assigned to them.

Confirmed on-chain

The deposit counts only after the confirmations the network needs to make it final.

Credited exactly once

The ledger credits the deposit keyed by its transaction hash. A repeated event changes nothing.

Reconciled with the chain

The balance on-chain and the balance in the ledger are compared, and they match.

Smart contracts, wallets, and multi-chain payment flows, built with the same rigor as the rest of your financial stack.

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What we build

Systems that move real value on-chain and keep a correct record of it off-chain.

Smart contracts and programs
Contracts and on-chain programs for payments, escrow, staking, and tokens, tested before they hold real value.
Wallets and custody flows
Deposit addresses, signing, and withdrawals with limits, approvals, and audit trails.
Multi-chain deposits and withdrawals
Solana, EVM networks, the XRP Ledger, and stablecoins like USDC and USDT.SolanaEVMXRP LedgerUSDCUSDT
Stablecoin and token integrations
Minting, transfers, and conversions between stablecoins, tokens, and fiat rails.
On-chain and off-chain reconciliation
Every on-chain movement matched to a ledger entry, and every ledger entry to a transaction.

How we build on-chain

  • Credit exactly once

    Deposits are keyed to their transaction, so reorgs and duplicate events never double-credit.

  • Finality before value

    Funds are credited only after the confirmations each chain needs.

  • Keys are a liability

    Signing is isolated, limited, and logged.

  • The chain is the source of truth

    Balances are reconciled against the chain, not only against our own records.

Case study

Multi-chain deposits for a card program

We built the deposit infrastructure that lets customers fund their cards from several blockchains, crediting each deposit exactly once.

What we built

  • Deposit addresses across multiple chains
  • Confirmation tracking per network
  • Idempotent crediting into a double-entry ledger
  • Stablecoin support, including USDC and USDT
  • Reconciliation between on-chain balances and the ledger
The ledger side of this work: Financial systems/financial-systems

Contact

Building on-chain?

Tell us what you are building. We will tell you how we would make it safe to hold real value.

Email
gustavo@tavin.dev
Include
What it should do, who uses it, and any deadline.
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