Solana Programs

Build on-chain Solana programs with Anchor - account constraints, instructions, and cross-program invocation in Rust.

Recipe

use anchor_lang::prelude::*;
 
declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");
 
#[program]
pub mod hello_anchor {
    use super::*;
 
    pub fn initialize(ctx: Context<Initialize>) -> Result<()> {
        ctx.accounts.counter.count = 0;
        Ok(())
    }
}
 
#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(init, payer = user, space = 8 + 8)]
    pub counter: Account<'info, Counter>,
    #[account(mut)]
    pub user: Signer<'info>,
    pub system_program: Program<'info, System>,
}
 
#[account]
pub struct Counter {
    pub count: u64,
}

When to reach for this:

• High-throughput DeFi, NFT, or gaming logic on Solana
• Teams wanting IDL-generated TypeScript/Rust clients
• Composable protocols via CPI to SPL Token and other programs

Working Example

Increment instruction with signer and account constraints:

use anchor_lang::prelude::*;
 
declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS");
 
#[program]
pub mod counter {
    use super::*;
 
    pub fn increment(ctx: Context<Increment>) -> Result<()> {
        ctx.accounts.counter.count = ctx.accounts.counter.count
            .checked_add(1)
            .ok_or(ProgramError::InvalidArgument)?;
        Ok(())
    }
}
 
#[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,
}

What this demonstrates:

• has_one ties signer to stored authority pubkey
• Checked add maps overflow to program error
• Account mutability declared explicitly in derive

Deep Dive

How It Works

• Transactions invoke programs with account metas (writable, signer).
• Anchor #[account(...)] macros validate owners, seeds, and rent.
• IDL describes instructions for client SDKs.
• CPI lets your program call SPL Token transfer with invoked signer seeds.

Account Types

Gotchas

• Account space too small - upgrade fails silently or rejects init. Fix: space = 8 + sizeof(T) plus discriminator.
• Missing signer on mut account - transaction simulation fails. Fix: mark Signer and mut correctly in Accounts struct.
• Compute budget exceeded - loop-heavy logic fails on mainnet. Fix: profile CU in local validator, optimize or split instructions.
• PDA seed collisions - bricked accounts. Fix: namespace seeds with program id and domain tags.
• Unchecked external accounts - arbitrary CPI targets drain funds. Fix: whitelist program IDs in constraints.

Alternatives

FAQs

Related

• Blockchain Basics in Rust - primitives
• Wallets & Key Management - signers
• Security & Auditing - vulnerabilities
• Applied Cryptography - hashes and curves

Stack versions: This page was written for Rust 1.97.0 (edition 2024), Tokio 1.x, Axum 0.8, serde 1.0, sqlx 0.8, clap 4, and Polars 0.46+.

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