Creating & Closing Accounts

Q: What does init do under the hood?

CPI to System Program create_account with space, owner, and lamports from payer.

Q: Who can close an account?

Your program via close constraint - typically requiring authority signer.

Q: Where do reclaimed lamports go?

The account specified in close = receiver.

Q: When is realloc needed?

When account data grows beyond originally allocated space.

Q: Can closed accounts be revived?

Same address can be re-initialized if recreated with init - treat as new account.

Q: How do I close multiple accounts at once?

Multiple close constraints in one instruction - watch CU limits.

Q: Does closing emit an event?

Not automatically. Add emit! for indexers.

Account creation allocates space, assigns an owner, and funds rent-exemption. Closing reclaims lamports. realloc grows or shrinks data in place.

Recipe

// Create
#[account(init, payer = payer, space = 8 + MyData::INIT_SPACE)]
pub data: Account<'info, MyData>,
 
// Grow
#[account(mut, realloc = new_size, realloc::payer = payer, realloc::zero = false)]
pub data: Account<'info, MyData>,
 
// Close
#[account(mut, close = receiver)]
pub data: Account<'info, MyData>,

When to reach for this:

User onboarding flows that create PDAs or config accounts
Migration instructions that expand account size
Cleanup incentives returning rent to users
Protocol shutdown reclaiming vault accounts

Working Example

use anchor_lang::prelude::*;
 
#[program]
pub mod lifecycle {
    use super::*;
 
    pub fn create(ctx: Context<Create>, label: String) -> Result<()> {
        ctx.accounts.data.authority = ctx.accounts.payer.key();
        ctx.accounts.data.label = label;
        Ok(())
    }
 
    pub fn expand(ctx: Context<Expand>, extra: u32) -> Result<()> {
        ctx.accounts.data.extra = extra;
        Ok(())
    }
 
    pub fn close_account(ctx: Context<CloseData>) -> Result<()> {
        Ok(())
    }
}
 
#[account]
#[derive(InitSpace)]
pub struct MyData {
    pub authority: Pubkey,
    #[max_len(20)]
    pub label: String,
    pub extra: u32,
}
 
#[derive(Accounts)]
pub struct Create<'info> {
    #[account(init, payer = payer, space = 8 + MyData::INIT_SPACE)]
    pub data: Account<'info, MyData>,
    #[account(mut)]
    pub payer: Signer<'info>,
    pub system_program: Program<'info, System>,
}
 
#[derive(Accounts)]
pub struct Expand<'info> {
    #[account(
        mut,
        realloc = 8 + MyData::INIT_SPACE,
        realloc::payer = payer,
        realloc::zero = false,
    )]
    pub data: Account<'info, MyData>,
    #[account(mut)]
    pub payer: Signer<'info>,
    pub system_program: Program<'info, System>,
}
 
#[derive(Accounts)]
pub struct CloseData<'info> {
    #[account(mut, close = receiver, has_one = authority)]
    pub data: Account<'info, MyData>,
    pub authority: Signer<'info>,
    #[account(mut)]
    pub receiver: SystemAccount<'info>,
}

What this demonstrates:

init CPIs to System Program for allocation + rent transfer
realloc may require additional lamports from realloc::payer
close zeros data and sends all lamports to receiver

Deep Dive

Creation Steps (Runtime)

Payer signs and provides lamports
System Program allocates space bytes
Owner set to calling program
Program writes initial data

Close Safety

Anchor close sets lamports to 0 and assigns owner to System Program
Always verify authority before close to prevent griefing
Cannot close accounts that still hold unexpected funds (add constraints)

Gotchas

init without system_program - compile/runtime failure. Fix: always include Program<'info, System>.
Realloc shrink losing data - truncates bytes. Fix: migrate data before shrinking or only grow.
Closing accounts referenced elsewhere - downstream indexers break. Fix: emit event and document lifecycle.
Forgot mut on payer for realloc - insufficient funding. Fix: mark payer mut when realloc may cost lamports.
Closing token accounts with balance - SPL requires empty balance first. Fix: transfer tokens then close via SPL CPI.

Alternatives

Alternative	Use When	Don't Use When
`init_if_needed`	Idempotent onboarding	Strict one-time creation security
Manual System CPI	Native programs without Anchor	Anchor projects (use macros)
New account migration	Breaking layout changes	Minor field additions
`realloc`	Modest size growth	Large dataset changes (new PDA)

FAQs

What does init do under the hood?

CPI to System Program create_account with space, owner, and lamports from payer.

Who can close an account?

Your program via close constraint - typically requiring authority signer.

Where do reclaimed lamports go?

The account specified in close = receiver.

When is realloc needed?

When account data grows beyond originally allocated space.

Does realloc cost extra rent?

Yes, if larger size requires higher rent-exempt minimum. Payer funds difference.

Can I close a PDA?

Yes. Program signs if needed; lamports go to receiver.

What is init_if_needed?

Creates account only if it doesn't exist - useful for ATAs-like patterns with care.

Can closed accounts be revived?

Same address can be re-initialized if recreated with init - treat as new account.

How do I close multiple accounts at once?

Multiple close constraints in one instruction - watch CU limits.

Does closing emit an event?

Not automatically. Add emit! for indexers.

Can users close accounts without program?

System-owned empty accounts can be drained; program-owned require program instruction.

What is realloc::zero?

Whether new bytes are zeroed. false preserves existing data during growth.

Rent & Rent-Exemption - funding amounts
Data Accounts & Layout - space planning
Program-Owned State - PDA creation

Stack versions: This page was written for Agave 4.1.1, Solana CLI 3.0.10, Anchor 0.32.1, anchor-lang 0.32.1, Rust 1.91.1, @solana/kit 7.0.0, Surfpool 0.12.0, and LiteSVM 0.6.x.

Recipe

// Create
#[account(init, payer = payer, space = 8 + MyData::INIT_SPACE)]
pub data: Account<'info, MyData>,
 
// Grow
#[account(mut, realloc = new_size, realloc::payer = payer, realloc::zero = false)]
pub data: Account<'info, MyData>,
 
// Close
#[account(mut, close = receiver)]
pub data: Account<'info, MyData>,

When to reach for this:

User onboarding flows that create PDAs or config accounts
Migration instructions that expand account size
Cleanup incentives returning rent to users
Protocol shutdown reclaiming vault accounts

Working Example

use anchor_lang::prelude::*;
 
#[program]
pub mod lifecycle {
    use super::*;
 
    pub fn create(ctx: Context<Create>, label: String) -> Result<()> {
        ctx.accounts.data.authority = ctx.accounts.payer.key();
        ctx.accounts.data.label = label;
        Ok(())
    }
 
    pub fn expand(ctx: Context<Expand>, extra: u32) -> Result<()> {
        ctx.accounts.data.extra = extra;
        Ok(())
    }
 
    pub fn close_account(ctx: Context<CloseData>) -> Result<()> {
        Ok(())
    }
}
 
#[account]
#[derive(InitSpace)]
pub struct MyData {
    pub authority: Pubkey,
    #[max_len(20)]
    pub label: String,
    pub extra: u32,
}
 
#[derive(Accounts)]
pub struct Create<'info> {
    #[account(init, payer = payer, space = 8 + MyData::INIT_SPACE)]
    pub data: Account<'info, MyData>,
    #[account(mut)]
    pub payer: Signer<'info>,
    pub system_program: Program<'info, System>,
}
 
#[derive(Accounts)]
pub struct Expand<'info> {
    #[account(
        mut,
        realloc = 8 + MyData::INIT_SPACE,
        realloc::payer = payer,
        realloc::zero = false,
    )]
    pub data: Account<'info, MyData>,
    #[account(mut)]
    pub payer: Signer<'info>,
    pub system_program: Program<'info, System>,
}
 
#[derive(Accounts)]
pub struct CloseData<'info> {
    #[account(mut, close = receiver, has_one = authority)]
    pub data: Account<'info, MyData>,
    pub authority: Signer<'info>,
    #[account(mut)]
    pub receiver: SystemAccount<'info>,
}

What this demonstrates:

init CPIs to System Program for allocation + rent transfer
realloc may require additional lamports from realloc::payer
close zeros data and sends all lamports to receiver

Deep Dive

Creation Steps (Runtime)

Payer signs and provides lamports
System Program allocates space bytes
Owner set to calling program
Program writes initial data

Close Safety

Anchor close sets lamports to 0 and assigns owner to System Program
Always verify authority before close to prevent griefing
Cannot close accounts that still hold unexpected funds (add constraints)

Gotchas

init without system_program - compile/runtime failure. Fix: always include Program<'info, System>.
Realloc shrink losing data - truncates bytes. Fix: migrate data before shrinking or only grow.
Closing accounts referenced elsewhere - downstream indexers break. Fix: emit event and document lifecycle.
Forgot mut on payer for realloc - insufficient funding. Fix: mark payer mut when realloc may cost lamports.
Closing token accounts with balance - SPL requires empty balance first. Fix: transfer tokens then close via SPL CPI.

Alternatives

Alternative	Use When	Don't Use When
`init_if_needed`	Idempotent onboarding	Strict one-time creation security
Manual System CPI	Native programs without Anchor	Anchor projects (use macros)
New account migration	Breaking layout changes	Minor field additions
`realloc`	Modest size growth	Large dataset changes (new PDA)

FAQs

What does init do under the hood?

CPI to System Program create_account with space, owner, and lamports from payer.

Who can close an account?

Your program via close constraint - typically requiring authority signer.

Where do reclaimed lamports go?

The account specified in close = receiver.

When is realloc needed?

When account data grows beyond originally allocated space.

Does realloc cost extra rent?

Yes, if larger size requires higher rent-exempt minimum. Payer funds difference.

Can I close a PDA?

Yes. Program signs if needed; lamports go to receiver.

What is init_if_needed?

Creates account only if it doesn't exist - useful for ATAs-like patterns with care.

Can closed accounts be revived?

Same address can be re-initialized if recreated with init - treat as new account.

How do I close multiple accounts at once?

Multiple close constraints in one instruction - watch CU limits.

Does closing emit an event?

Not automatically. Add emit! for indexers.

Can users close accounts without program?

System-owned empty accounts can be drained; program-owned require program instruction.

What is realloc::zero?

Whether new bytes are zeroed. false preserves existing data during growth.

Rent & Rent-Exemption - funding amounts
Data Accounts & Layout - space planning
Program-Owned State - PDA creation

Stack versions: This page was written for Agave 4.1.1, Solana CLI 3.0.10, Anchor 0.32.1, anchor-lang 0.32.1, Rust 1.91.1, @solana/kit 7.0.0, Surfpool 0.12.0, and LiteSVM 0.6.x.

Creating & Closing Accounts

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Creating & Closing Accounts