Token contracts
Fungible and non-fungible tokens with the minting, supply, and permission rules your product needs.
Smart contract development tested like money depends on it.
Velvy writes smart contracts in Solidity for EVM chains and in Move for Sui. EVM contracts ship with a Foundry test suite of unit, fuzz, and invariant tests; Move contracts ship with their own test suite; both come with scripted deployments and documentation an independent auditor can work from. We also build the front end and backend that call the contracts, so the whole system is designed together.
Spec/services/smart-contract-development
Best-fit engagement
Milestone-based hourly
Per milestoneBuilt with
- Solidity
- Foundry
- Sui Move
- ethers
- viem
- TypeScript
- Node.js
Working
Deployed to production
Tested
Automated tests and evals
Observable
Logs, traces, and alerts
What we build
Contracts small enough to reason about, tested hard enough to ship.
Application logic
Escrow, vesting, staking, marketplace, and payment flows written as small, auditable contracts.
Access control and upgrades
Roles, pausing, and upgrade paths chosen deliberately, or immutability when that is the safer design.
Test suites
Foundry unit, fuzz, and invariant tests for EVM contracts, plus fork tests against live network state.
Deployment and verification
Scripted, repeatable deployments, verified source code, and a record of every deployed address and setting.
Audit preparation
Specs, threat notes, and tests packaged for an independent auditor, then fixes for whatever the audit finds.
How we build it
Specify, test, then deploy.
The stack
- Solidity
- Foundry
- Sui Move
- ethers
- viem
- TypeScript
- Node.js
01
Write the spec
Plain-language rules for who can do what, and the invariants that must always hold, agreed before any code.
02
Keep contracts small
Less code is less attack surface. Logic that does not need to be onchain stays offchain.
03
Test adversarially
Fuzz and invariant tests try to break the rules in the spec, alongside unit and fork tests.
04
Rehearse the deploy
Scripted deployments run on testnets and forks first, with admin keys and settings checked.
How to engage
Start with Milestone-based hourly.
Contract work fits milestone-based hourly: spec, implementation, test suite, and deployment as separate milestones, with audit fixes scoped once the report arrives.
We start with paid discovery, never an unpaid test project, so the plan rests on your real requirements.
Milestone-based hourly
Per milestoneHourly work organized into agreed milestones, each with clear acceptance criteria.
Also fits
Fractional engineering
2–3 days a weekFor a protocol that keeps evolving, fractional engineering keeps the same engineer on the contracts and the app.
Common questions
Smart contract development, answered.
Something else on your mind? Ask us directly at hello@velvy.ai, or book the intro call below.
Do you audit smart contracts?
No. We write and test contracts and prepare them for audit, but an audit should come from an independent firm that did not write the code. We help you scope the audit and fix what it finds.
Which languages and chains do you write contracts for?
Solidity for Ethereum and EVM-compatible chains, with Foundry for testing and deployment, and Move for Sui. On Solana and TON we build the application side that talks to onchain programs rather than the programs themselves.
What are fuzz and invariant tests?
Fuzz tests call a function with large numbers of generated inputs to find edge cases nobody thought to write down. Invariant tests check that rules which must always hold, such as total supply matching the sum of balances, stay true across random sequences of calls. Foundry supports both.
Should our contracts be upgradeable?
It depends on what your users need to trust. Upgradeability lets you fix bugs, but it means someone holds the power to change the rules. We walk through the trade-off with you and design the admin controls either way.
Can any developer guarantee a contract has no bugs?
No, and be wary of anyone who says otherwise. What careful engineering does is reduce risk: small contracts, written invariants, adversarial tests, rehearsed deployments, and an independent audit before significant value is at stake.
Get started
Bring the messy problem. Leave with a plan.
Book an intro call. Tell us what you’re trying to build or automate, and we’ll tell you plainly whether we’re a fit and what a first engagement would look like.
Prefer email? hello@velvy.ai