@repla/sdk-ts

TypeScript SDK for the REPLA framework — a workbench for Solana game-specific L3 rollups. It gives you three things: an HTTP client for the REPLA backend API, the byte-identical state-root hash the Rust sequencer runtime uses, and helpers for deriving the on-chain settler program's PDAs.

REPLA settles game state to Solana via an Anchor program and runs live state inside a MagicBlock-backed sequencer. The settler program is currently deployed on mainnet.

Install

npm i @repla/sdk-ts

Requires Node ≥ 20.

Exports

| Export | Kind | What it does | | --- | --- | --- | | ReplaClient | class | HTTP client for the REPLA backend API (/api/health, /api/launch, /api/stats, /api/settle). | | computeStateRoot(payloads) | fn | 32-byte root over raw payloads; byte-identical to the Rust runtime's batch.rs. | | stateRootFromOps(ops) / merkleRoot(leaves) | fn | Apply 40-byte ledger ops ({ account, delta }) to a sorted balance ledger and Merkle-commit the resulting state; byte-identical to the Rust runtime's state machine. | | bytesToHex(bytes) | fn | Lowercase hex encoding of a byte array. | | REPLA_PROGRAM_ID | const | Settler program id (mainnet 42LxZ…). | | registryPda / sequencerPda / l3Pda / settlementPda | fn | Derive the settler program's PDAs. | | l3IdFromString(hex) | fn | Parse a 64-char hex id into a 32-byte Uint8Array. | | defaultConnection() / PUBLIC_MAINNET_RPC | fn / const | Convenience Connection to the public mainnet-beta RPC. | | LaunchConfig, LaunchResponse, StatsResponse, SettleRequest, Engine, GameType, LedgerOp | type | Request / response shapes for the API, plus the ledger op shape. |

REPLA API client

ReplaClient is a thin HTTP client over the REPLA backend service. It does not sign or send Solana transactions itself — it calls the REPLA API, which queues the on-chain work and reports status.

import { ReplaClient } from '@repla/sdk-ts';

const client = new ReplaClient({ apiUrl: 'https://api.repla.fun' });

const health = await client.health(); // { ok, version, network }
const stats = await client.stats();   // { sequencer_count, l3_count, settlement_count, ... }

const launch = await client.launchL3({
  game_name: 'my-game',
  engine: 'web',
  owner: 'YOUR_OWNER_PUBKEY',
});

const settle = await client.settle({
  l3_id: '00'.repeat(32),
  from_slot: 1,
  to_slot: 200,
  state_root: '00'.repeat(32),
  action_count: 0,
  sequencer: 'YOUR_SEQUENCER_PUBKEY',
}); // { queued, tx_intent }

Pass a custom fetchImpl (new ReplaClient({ apiUrl, fetchImpl })) to run the client outside a runtime that has a global fetch.

State root

import { computeStateRoot, bytesToHex } from '@repla/sdk-ts';

const payloads = [new Uint8Array([0x61]), new Uint8Array([0x62, 0x62])];
const root = computeStateRoot(payloads);
console.log(bytesToHex(root));

computeStateRoot takes the ordered action payloads and returns the 32-byte root: each payload is prefixed with its 4-byte little-endian length, then the whole stream is hashed once with SHA-256. This is byte-identical to the Rust sequencer runtime (packages/sequencer-runtime/src/batch.rs), so the same inputs produce the same root the chain settles against.

PDAs

import { PublicKey } from '@solana/web3.js';
import {
  registryPda,
  sequencerPda,
  l3Pda,
  settlementPda,
  l3IdFromString,
} from '@repla/sdk-ts';

const [registry] = registryPda();
const [sequencer] = sequencerPda(new PublicKey('OPERATOR_PUBKEY'));
const l3Id = l3IdFromString('00'.repeat(32));
const [l3] = l3Pda(l3Id);
const [settlement] = settlementPda(l3Id, 200n); // toSlot is a bigint

Each helper returns the [PublicKey, bump] tuple from PublicKey.findProgramAddressSync and derives against REPLA_PROGRAM_ID by default; pass a different program id as the last argument to target another deployment.

On-chain

Anchor settler program (mainnet): 42LxZbUQHUSiBvuVzo1YtAxbjDbxLDLHNmQhyG5wabVV. Mainnet deploy is scheduled into the launch sequence.

Related

• repla-cli — terminal interface, uses this SDK under the hood.
• @repla/magicblock-adapter — binds the sequencer runtime to MagicBlock Ephemeral Rollups.

Links

• Site — https://repla.fun
• Diorama — https://repla.fun/diorama
• Bench — https://repla.fun/bench
• Reference crate — https://github.com/replalabs/repla-core
• X — https://x.com/replagg

License

Apache-2.0.