What are Smart Contracts?

By: WEEX|Sep 19, 2025

Intro to Smart Contracts

Smart contracts are self-executing agreements written in code and deployed on a blockchain. They automatically enforce the terms of an agreement between parties when predefined conditions are met, removing the need for intermediaries. By automating transactions, smart contracts enhance efficiency, reduce costs, and increase transparency and trust across a variety of industries. These intelligent contracts represent a fundamental shift in digital agreement design and execution.

Before the advent of smart contracts, it was difficult to create decentralized systems where multiple parties could transact without relying on a central authority. Platforms like Uber and Airbnb, for instance, depend on a central entity to manage transactions and enforce rules between users and service providers.

With the emergence of blockchain technology, smart contracts offer a more secure, efficient, and trustless way to execute agreements. They enable direct peer-to-peer transactions, opening the door to a new generation of decentralized applications.

This article explores what smart contracts are, how they work, their benefits and limitations, and the transformative impact they are having across numerous sectors.

What Are Smart Contracts?

A smart contract is a self-executing program stored on a blockchain that runs automatically when specific conditions are satisfied. Unlike traditional contracts, which rely on legal language and third-party enforcement, smart contracts operate based on code.

A useful analogy is a vending machine: you insert payment, and the machine automatically dispenses the product. Similarly, smart transactions eliminate manual intervention and reduce the need for intermediaries.

Because they reside on a decentralized blockchain, smart contracts are transparent, tamper-resistant, and immutable once deployed. This ensures reliability and security across various use cases.

The History and Evolution of Smart Contracts

The term "smart contract" was coined in 1994 by computer scientist and legal scholar Nick Szabo, who also conceptualized "Bit Gold" in 1998—a precursor to Bitcoin. He envisioned computerized protocols that could execute contract terms automatically, inspired by electronic systems like point-of-sale terminals.

In a 1996 paper, Szabo defined a smart contract as:

"a set of promises, specified in digital form, including the protocols within which the parties perform on the other promises."

He accurately predicted that financial instruments such as derivatives and securities could be standardized and traded efficiently via automated systems.

While some have speculated that Szabo might be Bitcoin’s anonymous creator, Satoshi Nakamoto, he has denied this. Nevertheless, his work laid the theoretical foundation for smart contracts long before blockchain technology existed.

How Do Smart Contracts Work?

Smart contracts operate using simple "if-then" logic. They are triggered by specific events—such as a payment, a date, or an input from an external data source (via "oracles").

Once deployed on a blockchain, the contract is distributed across the network. Each node validates the conditions and execution, ensuring consensus and transparency. When the conditions are met, the contract automatically performs the agreed-upon actions.

Although Ethereum popularized smart contracts, many other blockchains—including Solana, Cardano, Polkadot, and Tezos—now support them. Developers write smart contracts in programming languages such as Solidity, Plutus, and Michelson. Many projects also rely on smart contract templates to accelerate development and improve security.

This automation enables more efficient and secure processes in areas like finance, real estate, and supply chain management.

Pros and Cons of Smart Contracts

Pros

Automation & Efficiency: Self-executing contracts save time and reduce manual effort.
Cost Reduction: Removing intermediaries lowers transaction fees.
Transparency & Trust: Terms and executions are visible and verifiable by all parties.
Security: Cryptographic encryption and decentralization help prevent fraud and tampering.

Cons

Rigidity: Contracts are only as good as their code. They lack flexibility for unplanned scenarios or subjective interpretations.
Difficulty Updating: Fixing bugs or changing terms requires broad consensus and is often complex.
Dependence on Oracles: Many contracts need external data, which must be reliably supplied—introducing potential complexity and points of failure.

Use Cases of Smart Contracts

Smart contracts are already transforming industries by enabling trustless automation and reducing operational costs. Many people also explore how to make money with smart contracts through yield farming, NFT minting, and decentralized app (dApp) development.

Mortgages Automating verification, payment schedules, and fund disbursement speeds up processes and reduces the need for banks or lawyers.
Digital Identity Individuals can control and share personal data securely without intermediaries. Estonia’s blockchain-based digital ID system is a leading example.
Supply Chain Every step of a product’s journey can be recorded on a blockchain, increasing traceability and reducing fraud.
Bank Bot Smart Contracts Automated banking agents powered by smart contracts can handle loans, payments, and compliance checks without human intervention, streamlining financial operations.
DeFi and Etherions Core Smart Contracts Embedded Many decentralized finance platforms rely on highly optimized smart contract systems like Etherions core smart contracts embedded in their architecture to ensure security and high-performance transactions.

Challenges and the Road Ahead

Despite their potential, smart contracts are not without risks. The infamous DAO hack in 2016, where millions in ETH were stolen due to a code vulnerability, highlighted the importance of security audits and careful design.

Because smart contracts are immutable, errors can be costly. Today, many projects rely on professional third-party audits to minimize risks.

Still, the technology is young and evolving. As tools and best practices improve, smart contracts are expected to gain broader adoption.

Conclusion

Smart contracts represent a major shift in how agreements are made and executed. By replacing intermediaries with transparent and automated code, they reduce cost and build trust between parties.

While challenges around security, flexibility, and real-world data integration remain, the potential applications are vast and transformative. From intelligent contracts in governance to automated bank bot smart contracts in finance, the technology is paving the way for a more efficient digital economy.

The technology is still developing, and wider acceptance appears inevitable as blockchain ecosystems mature and more industries recognize the benefits of decentralized, self-executing contracts.