ZK Compression on Solana

ZK Compression enables rent-free tokens and PDAs on Solana by storing state on the ledger instead of in accounts, using zero-knowledge proofs to validate state transitions. Built by Light Protocol and indexed by Helius Photon.

When to Use ZK Compression

Use ZK Compression when:

Creating millions of token accounts (5000x cheaper than regular accounts)
Minting to many recipients (airdrops, loyalty programs, gaming assets)
Building apps with many user accounts that are infrequently updated
Reducing rent costs for PDAs with low update frequency

Use regular accounts when:

Account is updated frequently (>1000 lifetime writes)
Account stores large data accessed in on-chain transactions
Compute budget is critical (compression adds ~100k CU overhead)

Quick Start

Installation

# TypeScript client
npm install @lightprotocol/stateless.js @lightprotocol/compressed-token

# Rust SDK for programs
cargo add light-sdk

# CLI for development
npm install -g @lightprotocol/zk-compression-cli

Local Development

# Start local validator with compression support
light test-validator

# Initialize a new Anchor project with compression
light init my-program

Mint Compressed Tokens (TypeScript)

import { createRpc } from '@lightprotocol/stateless.js';
import { createMint, mintTo, transfer } from '@lightprotocol/compressed-token';

const rpc = createRpc(); // or createRpc('https://mainnet.helius-rpc.com?api-key=YOUR_KEY')

// Create mint with token pool for compression
const { mint } = await createMint(rpc, payer, payer.publicKey, 9);

// Mint compressed tokens (creates compressed token accounts)
await mintTo(rpc, payer, mint, recipient, payer, 1_000_000_000);

// Transfer compressed tokens
await transfer(rpc, payer, mint, 500_000_000, owner, recipient);

// Query compressed token accounts
const accounts = await rpc.getCompressedTokenAccountsByOwner(owner, { mint });

Build Program with Compressed PDAs (Anchor)

use anchor_lang::prelude::*;
use light_sdk::{
    account::LightAccount,
    address::v1::derive_address,
    cpi::{v1::CpiAccounts, CpiSigner},
    derive_light_cpi_signer,
    instruction::{account_meta::CompressedAccountMeta, PackedAddressTreeInfo, ValidityProof},
    LightDiscriminator, LightHasher,
};

declare_id!("YourProgramID");

pub const LIGHT_CPI_SIGNER: CpiSigner = derive_light_cpi_signer!("YourProgramID");

#[program]
pub mod my_program {
    use super::*;
    use light_sdk::cpi::{v1::LightSystemProgramCpi, InvokeLightSystemProgram};

    pub fn create_account<'info>(
        ctx: Context<'_, '_, '_, 'info, MyAccounts<'info>>,
        proof: ValidityProof,
        address_tree_info: PackedAddressTreeInfo,
        output_state_tree_index: u8,
    ) -> Result<()> {
        let light_cpi_accounts = CpiAccounts::new(
            ctx.accounts.signer.as_ref(),
            ctx.remaining_accounts,
            crate::LIGHT_CPI_SIGNER,
        );

        let (address, address_seed) = derive_address(
            &[b"my_account", ctx.accounts.signer.key().as_ref()],
            &address_tree_info.get_tree_pubkey(&light_cpi_accounts)?,
            &crate::ID,
        );

        let new_address_params = address_tree_info.into_new_address_params_packed(address_seed);

        // Create new compressed account
        let mut account = LightAccount::<MyAccount>::new_init(
            &crate::ID,
            Some(address),
            output_state_tree_index,
        );
        account.owner = ctx.accounts.signer.key();
        account.data = 0;

        LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, proof)
            .with_light_account(account)?
            .with_new_addresses(&[new_address_params])
            .invoke(light_cpi_accounts)?;

        Ok(())
    }

    pub fn update_account<'info>(
        ctx: Context<'_, '_, '_, 'info, MyAccounts<'info>>,
        proof: ValidityProof,
        current_data: u64,
        account_meta: CompressedAccountMeta,
    ) -> Result<()> {
        // Modify existing compressed account
        let mut account = LightAccount::<MyAccount>::new_mut(
            &crate::ID,
            &account_meta,
            MyAccount {
                owner: ctx.accounts.signer.key(),
                data: current_data,
            },
        )?;

        account.data = account.data.checked_add(1).unwrap();

        let light_cpi_accounts = CpiAccounts::new(
            ctx.accounts.signer.as_ref(),
            ctx.remaining_accounts,
            crate::LIGHT_CPI_SIGNER,
        );

        LightSystemProgramCpi::new_cpi(LIGHT_CPI_SIGNER, proof)
            .with_light_account(account)?
            .invoke(light_cpi_accounts)?;

        Ok(())
    }
}

#[derive(Accounts)]
pub struct MyAccounts<'info> {
    #[account(mut)]
    pub signer: Signer<'info>,
}

#[event]
#[derive(Clone, Debug, Default, LightDiscriminator, LightHasher)]
pub struct MyAccount {
    #[hash]
    pub owner: Pubkey,
    pub data: u64,
}

Core Concepts

Compressed Account Model

Compressed accounts are similar to regular Solana accounts but stored differently:

| Aspect | Regular Account | Compressed Account | |--------|-----------------|-------------------| | Storage | AccountsDB (disk) | Ledger (call data) | | Rent | Required (~0.002 SOL per 100 bytes) | None | | Identification | Pubkey | Hash (changes on write) or Address | | State validation | Runtime checks | ZK validity proofs |

Key differences:

Hash changes on every write (accounts identified by content hash)
Optional persistent address for PDAs (similar to regular PDAs)
State stored in Merkle trees with only roots on-chain

State Trees

Compressed accounts are stored in concurrent Merkle trees using Poseidon hashing:

Only the tree root is stored on-chain
Leaves contain compressed account hashes
Validity proofs prove account inclusion in tree

V2 Batched Merkle Trees (mainnet, January 2026): State root updates are batched and verified with ZK proofs, reducing costs by ~250x per update and overall CU usage by ~70% compared to V1 trees. V1 trees remain supported for existing deployments. New deployments automatically use V2 trees.

Validity Proofs

ZK proofs (Groth16) validate state transitions:

Prove existence of N accounts in M state trees
Constant 128-byte proof size regardless of accounts
~100k CU for proof verification

Transaction Lifecycle

Build: Client fetches compressed accounts and validity proofs via RPC
Submit: Transaction includes account data + proof in payload
Validate: Light System Program verifies proof and account integrity
Update: New state appended to tree, old state nullified
Index: Photon RPC nodes index new state from ledger

LightAccount Operations

// Create new account (no input state, only output)
let account = LightAccount::<T>::new_init(&program_id, Some(address), tree_index);

// Modify existing account (input + output state)
let mut account = LightAccount::<T>::new_mut(&program_id, &account_meta, current_state)?;
account.field = new_value;

// Close account (input state, no output)
let account = LightAccount::<T>::new_close(&program_id, &account_meta, current_state)?;

Helius SDK Integration

Query compressed state via Helius RPC:

import { Helius } from 'helius-sdk';

const helius = new Helius('YOUR_API_KEY');

// Get compressed account by hash or address
const account = await helius.zk.getCompressedAccount({ address });

// Get all compressed accounts for owner
const accounts = await helius.zk.getCompressedAccountsByOwner(owner);

// Get compressed token accounts
const tokenAccounts = await helius.zk.getCompressedTokenAccountsByOwner(owner, { mint });

// Get validity proof for accounts
const proof = await helius.zk.getValidityProof({ hashes: [hash1, hash2] });

// Get compression signatures for account
const signatures = await helius.zk.getCompressionSignaturesForAccount(hash);

RPC Methods

ZK Compression RPC API (via Helius or self-hosted Photon):

| Method | Description | |--------|-------------| | getCompressedAccount | Get account by hash or address | | getCompressedAccountsByOwner | Get all accounts owned by pubkey | | getCompressedTokenAccountsByOwner | Get token accounts for owner | | getCompressedTokenBalancesByOwner | Get token balances summary | | getValidityProof | Get ZK proof for account inclusion | | getMultipleCompressedAccounts | Batch fetch accounts | | getCompressionSignaturesForAccount | Get transaction history |

Infrastructure

Node Types

| Node | Purpose | Run By | |------|---------|--------| | Photon RPC | Index compressed state, serve queries | Helius (canonical), self-host | | Prover | Generate validity proofs | Bundled with Photon or standalone | | Forester | Maintain state trees, empty nullifier queues | Light Protocol, community |

Running Photon Locally

# Install
cargo install photon-indexer

# Run against devnet
photon --rpc-url=https://api.devnet.solana.com

# With Postgres for production
photon --db-url=postgres://postgres@localhost/postgres --rpc-url=<RPC_URL>

# Load from snapshot for faster bootstrap
photon-snapshot-loader --snapshot-dir=~/snapshot --snapshot-server-url=https://photon-devnet-snapshot.helius-rpc.com

Trade-offs

| Consideration | Impact | |---------------|--------| | Larger transactions | +128 bytes for proof + account data in payload | | Higher CU usage | ~100k CU proof verification + ~6k CU per account | | Per-write cost | Each write nullifies old state, appends new | | Indexer dependency | Requires Photon RPC (or self-host) for queries |

Break-even analysis: With V2 batched trees, compressed accounts are cost-effective for significantly more writes than V1's ~1000 write threshold due to 250x cheaper state root updates. Exact break-even depends on tree utilization and batch sizes.

Reference Documentation

compressed-accounts.md - Detailed account model, hashing, addresses
compressed-tokens.md - Token operations, pools, batch operations
compressed-pdas.md - Building programs with compressed PDAs
client-integration.md - TypeScript/Rust client setup, RPC methods

solana-compression