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Introduction to Solana: Architecture, Infrastructure, Smart Contracts, and Accounts

A beginner-friendly guide explaining Solana's architecture, infrastructure, smart contracts and accounts.

Written by BuildBear Team on Jul 22, 2025

Introduction to Solana

Solana is one of the most advanced blockchains designed for high-performance decentralized applications. While many know Solana as a fast chain for NFTs and DeFi, there’s much more under the hood.

In this guide, we'll simplify Solana’s architecture, from how it structures data to how smart contracts execute.

Blockchain: The Foundation

At its core, a blockchain is a chain of blocks, where each block contains a list of transactions and links to the previous block using cryptographic hashes.

Each block on Solana contains:

  • Header: Stores metadata, the hash of the previous block, and a Merkle root summarizing transactions.
  • Transactions: These are instructions or value transfers from users.
  • Merkle Root: A special hash that allows quick verification that transactions inside the block haven’t been tampered with.

Blockchain

If even a small part of the block’s header changes, the entire block hash changes, breaking the chain. This ensures tamper-proof history.

Blockchain vs Traditional Databases

Unlike regular databases that allow updates and deletions, a blockchain is append-only, blocks can only be added, not removed or changed. This guarantees historical integrity.

Each new block references the previous block’s hash, forming a linked chain, hence the term blockchain.

Beyond Just a Cryptocurrency

While most people associate Solana with its native token SOL, Solana is much more than just that:

  • A high-performance blockchain platform
  • Supports 65,000+ transactions per second
  • Minimal transaction fees
  • Lightning-fast confirmations (usually under 400ms)

This scalability makes Solana ideal for:

  • Decentralized Finance (DeFi)
  • NFT marketplaces
  • Blockchain-based games
  • Enterprise-level dApps

Solana as a Decentralized Supercomputer

Think of Solana as a global, decentralized supercomputer:

  • The blockchain acts like its hard drive, recording all actions.
  • The SOL token is fuel, used to pay for network usage.
  • Validators are the processors, handling computations and confirming data.

Anyone can deploy and run programs (smart contracts) on Solana, similar to how apps run on a normal computer.

Interconnected dApps on Solana

What makes Solana unique is the composable nature of its dApps:

  • Developers can build on existing programs.
  • Example:
    1. Use a dApp that mints NFTs for game cards.
    2. Integrate another dApp for in-game currency.
    3. Add a leaderboard service from a third dApp.

This ecosystem of reusable components supercharges innovation.

Infrastructure: Nodes, Validators & Protocol

Nodes

A node is a computer participating in Solana’s network.

Types of nodes:

  • Validator Nodes: Propose and vote on new blocks.
  • RPC Nodes: Allow users/dApps to query data and send transactions.

Nodes work together via a peer-to-peer (P2P) network.

Validator Clients

Validator nodes run special software called validator clients. To avoid risks from single points of failure, Solana promotes client diversity.

Popular validator clients include:

  • Agave
  • Jito Labs
  • Firedancer
  • Sig

Protocol Rules

A protocol defines how nodes communicate, validate transactions, and maintain the blockchain.

Key protocol components:

  • P2P messaging rules
  • Transaction structure
  • Consensus algorithm
  • Incentive system

SOL tokens incentivize nodes to secure the network.

Security: Why SOL Matters

  • Validators receive SOL rewards for processing and validating transactions.
  • Without incentives, nodes wouldn’t have a reason to participate.

1 SOL = 1_000_000_000 lamports (the smallest unit)

Slots, Epochs, and Leaders

Slots

  • Time is divided into slots (400 milliseconds each).
  • A selected validator (called a leader) proposes a block during each slot.
  • If the leader misses their slot, the network moves on.

Epochs

  • Epoch = ~432,000 slots (about 2 days)
  • At the start of each epoch:
    • Stake distribution is recalculated.
    • A new leader schedule is created.

More stake means higher chances of being a leader.

Transactions & Instructions

On Solana, every action is a transaction, a message stored on-chain after being validated.

Each transaction consists of:

  • One or more instructions.
  • Instructions are like commands:
    • Transfer SOL
    • Call a smart contract function
    • Create an account

Multiple instructions can be bundled in a single transaction.

Smart Contracts on Solana

A smart contract is code deployed on-chain. Once deployed, it becomes immutable and self-executing.

Solana smart contracts:

  • Store critical data on-chain in accounts.
  • Run business logic when invoked via transactions.

Solana Virtual Machine (SVM)

  • Solana uses the Solana Virtual Machine (SVM) to execute smart contract code.
  • Written in Rust, the SVM can process thousands of transactions per second.

Note: Only transactions interacting with smart contracts are processed via the VM.

Solana Development Ecosystem

  • Rust: Primary language for writing smart contracts.
  • C and C++: Also supported for low-level developers.
  • JavaScript/TypeScript: Used for interacting with deployed contracts via Solana libraries (like @solana/web3.js).

Solana’s developer ecosystem offers:

  • SDKs
  • CLI tools
  • APIs for dApp integration

What Are Solana Accounts?

At its core, a Solana account is simply a container for data, identified by a unique address.

You can think of an account like a labeled folder, permanently recorded on-chain.

Solana programs don’t maintain internal storage, instead, everything is stored externally in accounts.

The Three Main Types of Solana Accounts

Solana divides accounts into three main categories:

User Accounts

  • Controlled by wallets.
  • Store SOL, tokens, or NFTs.
  • You interact with these accounts daily via Phantom, Trust, etc. wallets.

Data Accounts

  • Store application-specific data.
  • Could store token balances, staking states, metadata, or even the state of a dApp.
  • Controlled by a specific Solana program.

Program Accounts

  • Store compiled executable bytecode.
  • They are immutable after deployment.
  • Owned by the BPF Loader Program.
  • Think of them as the deployed smart contract code itself.

Solana Accounts

Understanding these distinctions is essential for any Solana developer.

Fields Inside Every Solana Account

Each Solana account contains several important fields:

  • Owner: The program that controls the account. For example, a token account would typically be owned by the SPL Token Program.
  • Executable: A boolean flag. If true, the account contains executable bytecode (program code).
  • Lamports: The amount of SOL (Solana’s native token) the account holds.
    • 1 SOL = 1_000_000_000 lamports
  • Data: Serialized binary data stored inside the account.
  • Rent Epoch: Tracks rent exemption status over time.

Every account, from your wallet address to a token mint address, follows the following model. Solana Account Fields

Take a look at the above account fields for different Solana account types: Solana Epoch Info

Rent and Rent Exemption on Solana

On Solana, storing data costs rent.

Originally:

  • Rent was deducted every epoch (approximately every 2 days).

But today:

  • Accounts must deposit enough SOL upfront to become rent-exempt.
  • Rent-exempt accounts remain permanently stored unless manually deleted.

When you create an account:

  • You calculate how much SOL to deposit for rent exemption.
  • This ensures your account’s data stays on-chain without additional payments.

Solana Rent

What Is an Epoch on Solana?

An epoch is a checkpoint period on Solana, typically lasting about 2 days.

During an epoch:

  • Validators vote and confirm blocks.
  • Staking rewards are calculated and distributed.
  • Cluster upgrades or network changes may occur.

Historically, rent collection happened per epoch. But now, upfront deposits handle rent automatically.

Solana Epoch Info

Conclusion

Solana isn’t just a fast blockchain, it’s a full-fledged decentralized platform supporting:

  • Scalable dApps
  • NFTs and DeFi products
  • Complex program logic through smart contracts
  • An ever-growing composable ecosystem

With concepts like slots, epochs, and validator client diversity, Solana balances decentralization, speed, and security, all critical components for next-gen blockchain platforms.

Much of the technical insight in this blog is made possible thanks to the excellent documentation and research shared by the Solana developer community. For deeper exploration and original sources, we encourage readers to refer to the official docs and foundational materials from Solana and Ackee.

For more blockchain tutorials blogs, and guides , follow BuildBear on Twitter or explore our developer docs.

Introduction to Solana: Architecture, Infrastructure, Smart Contracts, and Accounts - BuildBear Labs