First Program & dApp

avm use 0.32.1
anchor init hello_counter
cd hello_counter
anchor build && anchor test
anchor deploy --provider.cluster devnet
# then scaffold Next.js client with @solana/kit@7.0.0

use anchor_lang::prelude::*;
 
declare_id!("<GENERATED_PROGRAM_ID>");
 
#[program]
pub mod hello_counter {
    use super::*;
 
    pub fn initialize(ctx: Context<Initialize>) -> Result<()> {
        ctx.accounts.counter.count = 0;
        Ok(())
    }
 
    pub fn increment(ctx: Context<Increment>) -> Result<()> {
        ctx.accounts.counter.count = ctx.accounts.counter.count.checked_add(1).unwrap();
        Ok(())
    }
}
 
#[account]
pub struct Counter {
    pub count: u64,
}
 
#[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>,
}
 
#[derive(Accounts)]
pub struct Increment<'info> {
    #[account(mut)]
    pub counter: Account<'info, Counter>,
}

anchor build
anchor test          # uses LiteSVM or validator per Anchor.toml
anchor deploy --provider.cluster devnet
solana program show <PROGRAM_ID>

import { createSolanaRpc, address } from "@solana/kit";
 
const rpc = createSolanaRpc("https://api.devnet.solana.com");
const counter = address("<COUNTER_ACCOUNT_PUBKEY>");
 
const info = await rpc.getAccountInfo(counter, { encoding: "base64" }).send();
console.log("account data length:", info.value?.data.length);
// Wire Codama-generated increment ix in the next onboarding step

# Generate kit client from IDL (team Codama config)
npx codama run --config codama.json
 
# Map env vars
NEXT_PUBLIC_PROGRAM_ID=...
NEXT_PUBLIC_RPC_URL=https://api.devnet.solana.com