Crypto Payments & Reward Smart Contracts

Crypto payments fail for commercial reasons long before they fail technically. A customer pays in USDC on Polygon, the merchant banks in euros, a sales partner earns a percentage of that sale, and the finance lead needs one record that ties the three together. Card settlement covers part of that journey on its own timetable, and leaves partner rewards to a spreadsheet nobody trusts at month end.

We build the payment and reward layer for those flows: peer-to-peer and peer-to-business transfers, merchant settlement, escrow, and referral programmes that pay several levels from contract rules. Balances live on-chain where each participant can check their own, and the transaction history exports in a form your accountant can work with.

The problems we get called in for

A merchant accepts pay-ins in one asset and wants pay-outs in another, on a schedule, with a visible fee. Someone has to decide who absorbs the swap cost, what happens when gas spikes, and what a customer sees when a transfer confirms on one chain but is not credited on the other.

A platform owes money to people who do not work for it. Drivers, resellers, hosts, and affiliate partners earn a share of revenue and expect to withdraw without a finance team approving each transfer by hand. Once the programme has more than one level, the rules for who earns what become a product feature.

Funds sit in escrow until a milestone is delivered, an arbitrator signs off, or a timeout passes. The release conditions have to be obvious before anyone deposits, because a locked balance with unclear terms generates disputes.

Who this is for

• Marketplaces that collect from buyers and pay sellers, drivers, or hosts
• Merchants accepting crypto who want scheduled settlement to a treasury or a fiat off-ramp
• Companies running affiliate, reseller, or agent programmes with more than one level
• Fintech products adding transfers, balances, and payout screens
• Token projects that owe contributors or holders recurring rewards

What we deliver

Payment and escrow contracts

We implement the patterns that fit the commercial arrangement: deposit and release escrow with a named arbiter, milestone escrow with per-stage approvals, time-locked release, refund paths, and dispute windows with a defined duration. Release authority is a role rather than a hardcoded address, so staff changes do not require a redeployment. Where counterparties already trust an existing escrow contract, we integrate it.

Referral and reward distribution

The attribution model comes first: who counts as a referrer, at which level, for which product, and for how long. The on-chain piece holds and distributes value, while an off-chain service resolves eligibility from your orders and computes each participant's share. Multi-level trees, capped depth, vesting periods, and clawbacks stay configurable, because reward programmes change faster than contracts should.

Controls against abuse

Self-referral, duplicate reward addresses, circular trades, and signup farming all appear within weeks of a launch. We combine off-chain identity checks with on-chain limits: one payout address per verified participant, a minimum transaction age before a reward vests, per-account and per-period caps, a payout delay that feeds a review queue, and a pause function that halts distribution without touching held balances.

Settlement, batching, and who pays gas

Paying forty participants one transfer at a time wastes most of the budget on fees. For a stable participant list we use a distributor contract where each person claims a share, or post a Merkle root that holders claim against, while a short list is cheaper in one batched call. Claim-based designs move gas to the recipient, push designs keep it on the treasury, and sponsored transactions through a relayer suit onboarding while adding an operational wallet to fund and watch. The choice goes into the specification.

Bookkeeping across two ledgers

Chain state is the record for custody and payouts. Your accounting system remains the record for orders, invoices, VAT, payroll, and fiat movements. We build a daily export mapping each on-chain event to the internal order it belongs to, with reconciliation checks and alerts when the two disagree.

Legal and tax positions stay with you

We implement the technology. Legal, licensing, regulatory, tax, accounting, and investment questions remain the client's responsibility, to be settled with your own advisers in each market where you operate. That covers whether a reward structure counts as a security, which registrations you need, and how payouts are taxed. We document the architecture and produce the records your advisers ask for. We do not provide legal or tax advice.

How the engagement runs

Discovery takes about a week. You describe the money movement: who pays, who receives, in which assets, on which chains, who absorbs fees, and which systems need a record of it. We map it to a payment flow and list the open questions for your advisers.

Modelling follows. We decide what belongs on-chain, how roles and addresses are structured, whether payouts are claimed or pushed, how the contract can be paused or upgraded, and which keys control what. You receive a short specification for your lawyer or compliance officer to review before any code is written.

The build runs two to six weeks for a first release. Contracts arrive with tests, the off-chain attribution and indexing service comes with the admin screens your team needs, and the release is deployed to a testnet with real participants before mainnet. Anything holding customer funds goes through an external audit before launch, and we handle the remediation that follows, covered on our smart contract audit and remediation page.

Launch is staged, with caps on transfer size and daily volume for the first weeks, monitoring for failed transactions, and an incident runbook naming who acts when a key is compromised or a payout misbehaves. Handover includes the repository, deployment documentation, and a statement of who owns each admin key.

What it costs

Work is billed at our flat rate of $39 per hour, or as a fixed scope once discovery is complete. Teams with continuous contract and dashboard work usually move to a monthly capacity plan from $2,699. Both models are on the pricing page, with the typical orders we publish for other project types.

An escrow contract with one settlement path and clean tests is often a three to five week project. A programme with multi-level referral payouts, merchant settlement, batched distributions, and reconciliation reporting typically runs six to ten weeks. Scope moves with the number of chains, whether payouts are claimed or pushed, how much existing order data has to be imported, and whether you want a fiat off-ramp inside the flow. An external audit is quoted by the audit firm, outside our fee.

Proof

Send Crypto is a payments product for global peer-to-peer and peer-to-business transfers, built on Polygon with public Solidity contracts and refinements that followed an audit dated 24 October 2022. It shows payment rules on-chain where users can inspect them, and hardening that continued after launch.

OnlinePay Wallet covered native iOS and Android applications for a payments company processing high transaction volumes, including biometric login, encrypted local storage, identity verification hooks, and audit logging. It shows the account, compliance, and operations side of a money product shipping alongside the on-chain layer.

Coinage Wallet is a customised exchange platform built on the Peatio framework with client branding, multi-currency support, and security work around exchange operations. It shows we can take proven open-source financial infrastructure and turn it into a product a client can launch under their own name.

Related services

• Fintech and Web3 development for regulated financial products, wallets, and payment rails
• dApp development for the interface, indexing, and wallet connection work on top
• Smart contract development for the contract engineering and testing behind these builds
• Payment gateway integration when card and bank rails run beside the crypto flow
• Smart contract audit and remediation to close out audit findings before a mainnet release

Next step

Describe the money movement you have in mind: who pays, who receives, in which asset, and what has to happen before a payout releases. We will say what belongs on-chain, what stays in your database, and which questions to put to your advisers first.

Contact us with the flow you want to build, or run your requirements through the Vasilkoff.info estimator to get an initial scope and cost range.