How to Write Smart Contracts for Solana Without Going Mad from Boilerplate

If you've ever tried writing programs for Solana in pure Rust, you probably remember that feeling when five lines of business logic required writing fifty lines of account validation checks, manual deserialization via Borsh, and signature validation. Got the order of keys wrong in the transaction — you get a runtime error that sometimes takes hours to debug.

In the Ethereum world, developers have long been accustomed to Solidity and ready-made wrappers like Hardhat or Foundry. In Solana, the analogous standard became Anchor — a framework that handles all the routine work of data parsing, access control checks, and client code generation.

What Anchor Handles for You

Essentially, Anchor is a DSL (domain-specific language) on top of Rust. It doesn't change Solana's internal BPF execution model, but packages low-level calls into understandable declarative macros.

When you write a program with Anchor, the framework solves four main tasks:

1. Serialization and deserialization of account data without manual unpacking method calls.
2. Account constraint validation right in the structure signature via attributes (owner check, signature verification, memory initialization).
3. IDL (Interface Description Language) specification assembly — Ethereum's ABI equivalent.
4. Creation of ready-to-use TypeScript and Rust clients for interacting with the contract directly from the frontend or tests.

What the Code Looks Like in Practice

Let's look at a classic counter example. In the pure Solana SDK, you'd have to manually parse the byte array InstructionData, extract account slices, check is_signer on the caller's address, and validate the system program address.

Here's what the same contract looks like in Anchor:

use anchor_lang::prelude::*;

declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");

#[program]
mod counter {
    use super::*;

    pub fn initialize(ctx: Context<Initialize>, start: u64) -> Result<()> {
        let counter = &mut ctx.accounts.counter;
        counter.authority = *ctx.accounts.authority.key;
        counter.count = start;
        Ok(())
    }

    pub fn increment(ctx: Context<Increment>) -> Result<()> {
        let counter = &mut ctx.accounts.counter;
        counter.count += 1;
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(init, payer = authority, space = 48)]
    pub counter: Account<'info, Counter>,
    pub authority: Signer<'info>,
    pub system_program: Program<'info, System>,
}

#[derive(Accounts)]
pub struct Increment<'info> {
    #[account(mut, has_one = authority)]
    pub counter: Account<'info, Counter>,
    pub authority: Signer<'info>,
}

#[account]
pub struct Counter {
    pub authority: Pubkey,
    pub count: u64,
}

The difference is immediately apparent. All validation logic is moved to the Initialize and Increment structures.

The #[account(init, payer = authority, space = 48)] attribute tells the runtime: create a new account, allocate 48 bytes for it, and charge the rent to the authority wallet.

The #[account(mut, has_one = authority)] construct automatically checks that the authority field inside the Counter structure matches the passed account authority, and that this account actually signed the transaction. If there's no signature or a different wallet was passed, execution will abort before entering the function body increment.

IDL and Frontend Without the Headache

The most convenient thing in the Anchor bundle is the IDL file in JSON format. The compiler assembles it automatically when building the project.

The IDL describes all instructions, data structures, and possible custom error types of the program. Based on this file, the @anchor-lang/core library generates a typed interface for JavaScript or TypeScript.

You no longer need to remember byte offsets when assembling a transaction on the client. Calling a method from the frontend becomes a regular function call:

await program.methods
  .increment()
  .accounts({
    counter: counterPubkey,
    authority: wallet.publicKey,
  })
  .rpc();

TypeScript will highlight errors if you forget to pass a required account or specify the wrong argument type.

Built-in Fuzzing for Finding Vulnerabilities

In smart contracts, the cost of a mistake is too high, which is why testing plays a special role. The CLI includes integration with the Crucible tool for coverage-guided fuzzing testing.

The anchor fuzz init command generates a test harness, and anchor fuzz run runs it with random input data, trying to find edge cases that lead to panics or invalid account states. This helps catch non-obvious overflows or missed checks before deploying to a testnet.

# Инициализация фазз-тестов
anchor fuzz init program_name

# Запуск тестов в release-сборке
anchor fuzz run program_name test_name --release

Installation and Getting Started

For managing toolchain versions, developers created a special utility called AVM (Anchor Version Manager). This saves you from version conflicts between the Solana compiler and the framework itself, when different projects require different sub-versions.

The utility installs with a single line:

curl -sSfL https://raw.githubusercontent.com/otter-sec/anchor/master/avm/install | sh

After installation, you can switch to nightly builds or pin specific releases for your workspaces:

avm nightly
avm nightly --disable

Who Will Benefit from Anchor

If you're just getting started with Solana development, starting without Anchor is practically pointless. You'll spend weeks reinventing the wheel for account parsing and discriminator validation.

The framework covers the main needs:

• Gives Rust backend developers strict typing and protection against common validation vulnerability patterns.
• Gives frontend developers ready-made TypeScript types and convenient methods for sending transactions.

The only case where Anchor might seem excessive is writing micro-programs with extreme binary size optimization (compute budget limit), where literally every byte of instructions matters. In all other scenarios, it's the de facto standard that saves hundreds of hours of work.