@soroban-dev-kit/core

Framework-agnostic transaction lifecycle for Stellar/Soroban: the Connector/Submitter abstractions, the idle → simulating → simulated → signing → submitting → pending → success state machine, and two Submitter implementations — DirectSubmitter (the user's own account pays the fee) and RelayerSubmitter (a relay service sponsors it via the fee-bump pattern).

Most apps won't use this package directly — install @soroban-dev-kit/react instead, which wraps this in React hooks. Use core directly for a non-React integration (a CLI, a backend job, a different framework).

npm install @soroban-dev-kit/core @stellar/stellar-sdk

Example: simulate and submit a contract call

import { DirectSubmitter, NETWORK_PRESETS, buildContractCallTransaction } from "@soroban-dev-kit/core";
import { Keypair, TransactionBuilder, nativeToScVal } from "@stellar/stellar-sdk";

const network = NETWORK_PRESETS.testnet;
const submitter = new DirectSubmitter();
const keypair = Keypair.fromSecret("S...");

const unsignedXdr = await buildContractCallTransaction({
  sourceAddress: keypair.publicKey(),
  contractId: "C...",
  method: "transfer",
  args: [nativeToScVal(keypair.publicKey(), { type: "address" }), /* ... */],
  network,
});

const sim = await submitter.simulate(unsignedXdr, { network });

const signedTx = TransactionBuilder.fromXDR(sim.assembledTransactionXdr, network.networkPassphrase);
signedTx.sign(keypair);

const result = await submitter.submit(
  { kind: "signed-envelope", signedTransactionXdr: signedTx.toXDR() },
  { network },
);

What's in here

• DirectSubmitter, RelayerSubmitter, LaunchtubeAdapter — the Submitter implementations.
• TxLifecycle, TX_LIFECYCLE_TRANSITIONS — the write-transaction state machine.
• buildContractCallTransaction, simulateReadContract — transaction/simulation building blocks.
• signAuthEntriesForAddress, signAuthEntriesToPayload, getUnsignedAuthEntryAddresses — auth-entry signing for multi-signer and sponsor-as-source flows.
• NETWORK_PRESETS, fundTestnetAccount — network config and a testnet friendbot helper.

Full docs and the design rationale: see the soroban-dev-kit repo and its SKILL.md.