# Smart Contract & Protocol Development

> Smart contract development services: Solidity protocols engineered for invariants and upgradeability, verified before mainnet on EVM chains. By Sentient Arc.

The contract layer done right: Solidity protocols engineered around the invariants that must never break, with chain selection, gas, and upgradeability decided before a line ships.

## Deployed code holds money and cannot be patched
A contract carries a bar most software never faces: it holds value, everyone can read it, and there is no patch window after deployment. The bug you ship is the bug attackers get to keep.

Writing Solidity is the easy part. The hard part is the properties that must always hold under every ordering an adversary can arrange: no lost funds, no unauthorized mint, no reentrant drain.

## From chain choice to verified deploy
We start above the code: which chain or L2, which upgrade strategy, which trust assumptions, because those decisions constrain everything downstream and are the most expensive to reverse.

Then we engineer for correctness, not coverage: the invariants written down explicitly, adversarial tests and fuzzing aimed at them, and a staged release ladder that raises exposure only as the system holds.

## What we build
- **Protocol architecture**: Contract systems and trust boundaries designed before code: chain choice, module split, and upgrade strategy.
- **Invariant & fuzz testing**: The properties that must never break, written down and hammered with adversarial and property-based tests.
- **Upgradeability & admin**: Proxy patterns, timelocks, and access controls designed so governance and fixes do not widen the attack surface.
- **Gas & audit prep**: Gas profiling, storage-layout discipline, and documentation that makes an external audit fast and cheap.

## Stack
- **Contracts:** Solidity, Hardhat, Foundry
- **Verification:** Fuzzing, Invariant testing, Slither, Echidna
- **Chains:** Ethereum, L2 rollups, EVM chains

## FAQ
**What do your smart contract development services cover?**

Protocol architecture, Solidity implementation, invariant and fuzz testing, upgradeability, and gas and audit preparation, everything from chain selection to a verified, deployable contract system.

**Do you get contracts audited?**

We engineer for audit and prepare the codebase and documentation for one, and coordinate a third-party audit where value warrants it. We are the builders and the audit prep, not a substitute for an independent auditor.

**How do you reduce the risk of an exploit?**

By treating correctness as the deliverable: explicit invariants, adversarial and property-based fuzzing aimed at them, and a staged testnet-to-mainnet release ladder rather than a single risky launch.

**Which chains do you work on?**

Primarily the EVM ecosystem, Ethereum and its L2 rollups, in Solidity. For non-EVM chains we scope feasibility openly before committing to a build.

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Canonical page: https://www.sentientarc.com/capabilities/blockchain-development