Launchtube Plugin

A plugin for OpenZeppelin Relayer that simplifies submitting Stellar Soroban transactions by handling fees, sequence numbers, and retries.

Prerequisites

• Node.js >= 18
• pnpm >= 10
• OpenZeppelin Relayer

Installation & Setup

LaunchTube can be added to any OpenZeppelin Relayer in two ways:

1. Install from npm (recommended)

# From the root of your Relayer repository
cd plugins
pnpm add @openzeppelin/relayer-plugin-launchtube

2. Use a local build (for development / debugging)

# Clone and build the plugin
git clone https://github.com/openzeppelin/relayer-plugin-launchtube.git
cd relayer-plugin-launchtube
pnpm install
pnpm build

Now reference the local build from your Relayer’s plugins/package.json:

{
  "dependencies": {
    "@openzeppelin/relayer-plugin-launchtube": "file:../../relayer-plugin-launchtube",
  },
}

Install dependencies:

pnpm install

---

Create the plugin wrapper

Inside the Relayer create a directory for the plugin and expose its handler:

mkdir -p plugins/launchtube

plugins/launchtube/index.ts

export { handler } from '@openzeppelin/relayer-plugin-launchtube';

Provide a configuration file

Copy the bundled example and tweak it to your needs:

cp node_modules/@openzeppelin/relayer-plugin-launchtube/config.example.json plugins/launchtube/config.json

Edit plugins/launchtube/config.json (see Configuration section).

Your Relayer should now contain:

relayer/
└─ plugins/
   ├─ package.json              # lists the dependency
   └─ launchtube/
      ├─ index.ts
      └─ config.json

LaunchTube is now ready to serve Soroban transactions 🚀

Development

Building from Source

# Install dependencies
pnpm install

# Build the plugin
pnpm build

# Run tests
pnpm test

# Lint and format
pnpm lint
pnpm format

Overview

Launchtube accepts Soroban operations and handles all the complexity of getting them on-chain:

• Automatic fee bumping using a dedicated fund account
• Sequence number management with a pool of sequence accounts
• Transaction simulation and rebuilding
• Retry logic and error handling

Configuration

Create config.json in the plugin directory:

{
  "fundRelayerId": "launchtube-fund",
  "sequenceRelayerIds": ["launchtube-seq-001", "launchtube-seq-002"],
  "maxFee": 1000000,
  "network": "testnet",
  "rpcUrl": "https://soroban-testnet.stellar.org"
}

Configuration Options:

• fundRelayerId: Relayer ID for the account that pays fees
• sequenceRelayerIds: Array of relayer IDs for sequence accounts
• maxFee: Maximum fee in stroops (1 XLM = 10,000,000 stroops)
• network: Either "testnet" or "mainnet"
• rpcUrl: Stellar Soroban RPC endpoint

API Usage

Submit with Transaction XDR

Submit a complete, signed transaction:

curl -X POST http://localhost:8080/api/v1/plugins/launchtube/call \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "params": {
      "xdr": "AAAAAgAAAAA...",
      "sim": false
    }
  }'

Submit with Function and Auth

Submit just the Soroban function and auth entries:

curl -X POST http://localhost:8080/api/v1/plugins/launchtube/call \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "params": {
      "func": "AAAABAAAAAEAAAAGc3ltYm9s...",
      "auth": ["AAAACAAAAAEAAAA..."],
      "sim": true
    }
  }'

Parameters

• xdr (string): Complete transaction envelope XDR
• func (string): Soroban host function XDR
• auth (array): Array of Soroban authorization entry XDRs
• sim (boolean): Whether to simulate the transaction before submission

Note: Provide either xdr OR func+auth, not both.

Response

{
  "transactionId": "tx_123456",
  "status": "submitted",
  "hash": "1234567890abcdef..."
}

How It Works

1. Request Validation: Validates input parameters and extracts Soroban data
2. Sequence Account Pool: Acquires an available sequence account
3. Auth Checking: Validates authorization entries
4. Simulation (if enabled): Simulates transaction and rebuilds with proper resources
5. Fee Bumping: Fund account wraps transaction with fee bump
6. Submission: Sends to Stellar network

License

MIT License