---
title: "Smart contracts done right: Best practices that will save you from a hack"
url: "https://www.unknowngravity.com/en/articulos/contratos-inteligentes-bien-hechos-buenas-practicas-que-te-salvaran-de-un-hack"
site: Unknown Gravity
published: "2025-06-06T15:15:18+00:00"
modified: "2026-07-15T10:51:32+00:00"
language: en-US
description: Smart contracts are at the core of any blockchain project. However, their immutability and real fund management make them an attractive target for attackers.
section: "Home > Programming > Smart contracts done right: Best practices that will save you from a hack"
---

# Smart contracts done right: Best practices that will save you from a hack

Smart contracts are at the core of any blockchain project.

However, their immutability and real fund management make them an attractive target for attackers.

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**A single mistake can result in millions of dollars in losses and irreparable damage to reputation.**

Therefore, following good practices in development, testing and auditing is not optional: it's a critical need to ensure integrity and trust in your project.

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In this article, we'll review the keys to building well-designed smart contracts that minimize risks and avoid hacks.

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## Importance of a secure smart contract

- Contracts, once deployed, are immutable.
- Bugs can be exploited to steal funds, manipulate data, or block functions.
- A project's reputation is based on the trust of users and partners.
- Auditing and good practices significantly reduce the attack surface.

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## Best Practices for Developing Secure Smart Contracts

### 1. Write modular, readable code

- Divide the contract into modules with clear functions.
- It applies the principle of unique responsibility (each function does only one thing).
- Use clear and consistent names for variables and functions.

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This makes it easy to review, detect errors, and future extension.

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### 2. Use safe and tested design patterns

- **Pull over push**: To send funds, avoid sending ETH automatically; that the user withdraws (“pull payment”).
- **Checks-Effects-Interactions**: Order operations to avoid re-entries.
- **Ownable and roles**: Control access with standard contracts such as OpenZeppelin AccessControl.
- **Circuit Breaker**: Implement an “emergency switch” to stop functions in case of emergency.

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These patterns have proven effective in mitigating common vulnerabilities.

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### 3. Perform comprehensive and automated testing

- Implement unit tests for each function with frameworks such as Hardhat or Truffle.
- Try normal scenarios and borderline cases.
- Do integration and stress testing.
- Use static analysis and fuzz testing tools to detect bugs and vulnerabilities.

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Continuous testing allows faults to be detected before auditing and deployment.

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### 4. Version Control and Controlled Deployment

- Use a version control system such as Git to manage the code.
- Keep a clear history of peer-reviewed changes and merges.
- Use development and staging environments to test before deployment on mainnet.
- Consider using upgradable proxies and contracts to fix errors without losing state.

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Orderly control avoids human errors and allows traceability.

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### 5. Verification and external auditing

- Check the contract on browsers like Etherscan for transparency.
- Hire specialized external audits before the launch.
- Review audit reports with your team and correct anything detected.
- Perform frequent internal audits for future changes.

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Auditing is an essential extra layer to reinforce security.

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## Recommended tools for secure contracts

- **OpenZeppelin**: Audited libraries and contracts to implement standards and roles.
- **MythX and Slither**: Static analysis to detect vulnerabilities.
- **Hardhat and Foundry**: Robust frameworks for testing and deployment.
- **Etherscan**: Public verification and transparency of contracts.

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## Real cases that demonstrate the importance of safety

- **The DAO hack (2016):** Reentrancy exploit that led to millions of dollars in losses and a hard fork in Ethereum.
- **Parity multisig bug (2017):** A mistake in a multisig contract blocked more than 150,000 ETH.
- **Compound comptroller bug (2020):** Oracle vulnerability solved in time thanks to rigorous testing.

These examples underscore that security is at the core of every serious blockchain project.

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## Conclusion

Don't leave the security of your smart contracts to chance. Implement from the start:

- Modular and readable code
- Safe design patterns
- Automated and rigorous testing
- Version control and phased deployment
- External auditing and verification

Only then can you minimize risks and protect both your project and your users from critical hacks and failures.