Using Claude Code to Interface with JSON-RPC APIs

Claude Code is revolutionizing how developers interact with APIs, and JSON-RPC endpoints are no exception. In this guide, we'll explore how to use Claude Code to work with Stellar's Soroban RPC and other JSON-RPC APIs, making blockchain development faster and more intuitive.

What is Claude Code?

Claude Code is Anthropic's official CLI tool that brings AI assistance directly to your terminal. It can read files, execute commands, make API calls, and help you understand complex codebases—all through natural language conversation.

For blockchain developers working with JSON-RPC APIs like Soroban RPC, Claude Code offers a powerful way to:

Explore and understand API endpoints

Generate and test RPC requests

Debug responses and errors

Build integration code

Setting Up for Soroban RPC Development

Before diving in, ensure you have Claude Code installed and your LumenQuery API key ready.

# Install Claude Code
npm install -g @anthropic-ai/claude-code

# Set your API key
export LUMENQUERY_API_KEY="lq_your_api_key"

Exploring JSON-RPC Methods with Claude Code

One of Claude Code's strengths is helping you understand unfamiliar APIs. Simply ask it about available methods:

You: What JSON-RPC methods are available on Soroban RPC?

Claude Code: Soroban RPC provides these core methods:

Network & Health:
- getHealth - Check RPC server status
- getNetwork - Get network configuration
- getLatestLedger - Current ledger sequence

Transactions:
- simulateTransaction - Test transaction before submitting
- sendTransaction - Submit signed transaction
- getTransaction - Get transaction by hash
- getTransactions - Query multiple transactions

Contract Data:
- getLedgerEntries - Read contract state
- getEvents - Query contract events
- getFeeStats - Current fee statistics

Making RPC Calls with Claude Code

Claude Code can help you construct and execute JSON-RPC requests. Here's how to check the health of your Soroban RPC endpoint:

You: Make a getHealth request to the Soroban RPC at rpc.lumenquery.io

Claude Code: I'll make that request for you.

curl -X POST https://rpc.lumenquery.io \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $LUMENQUERY_API_KEY" \
  -d '{"jsonrpc":"2.0","id":1,"method":"getHealth"}'

Response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "status": "healthy"
  }
}

Building a Transaction Flow

Claude Code excels at helping you build complex multi-step workflows. Here's an example of simulating and submitting a transaction:

Step 1: Get the Latest Ledger

You: Get the latest ledger sequence from Soroban RPC

curl -X POST https://rpc.lumenquery.io \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $LUMENQUERY_API_KEY" \
  -d '{"jsonrpc":"2.0","id":1,"method":"getLatestLedger"}'

Step 2: Simulate Your Transaction

You: Help me simulate a transaction. I have this XDR: AAAAAgAAAA...

Claude Code can help you construct the proper request:

curl -X POST https://rpc.lumenquery.io \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $LUMENQUERY_API_KEY" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "simulateTransaction",
    "params": {
      "transaction": "AAAAAgAAAA..."
    }
  }'

Step 3: Analyze the Response

When you receive a complex response, ask Claude Code to explain it:

You: What does this simulation response mean? [paste response]

Claude Code: This simulation shows:
- Estimated resource usage (CPU, memory, ledger entries)
- Required fees based on current network conditions
- Any errors that would occur if submitted
- The expected result of contract invocation

Debugging RPC Errors

JSON-RPC errors can be cryptic. Claude Code helps decode them:

You: I got this error: {"code":-32602,"message":"invalid params"}

Claude Code: This error indicates your request parameters
are malformed. Common causes:

1. Missing required fields in params object
2. Incorrect data types (string vs number)
3. Malformed XDR encoding for transactions
4. Invalid account addresses or contract IDs

Let me see your request to identify the specific issue.

Generating Integration Code

Claude Code can generate production-ready code for your JSON-RPC integrations:

You: Generate a TypeScript function to call getLatestLedger
with proper error handling

interface RpcResponse<T> {
  jsonrpc: string;
  id: number;
  result?: T;
  error?: { code: number; message: string };
}

interface LatestLedger {
  id: string;
  sequence: number;
  protocolVersion: number;
}

async function getLatestLedger(): Promise<LatestLedger> {
  const response = await fetch('https://rpc.lumenquery.io', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-API-Key': process.env.LUMENQUERY_API_KEY!,
    },
    body: JSON.stringify({
      jsonrpc: '2.0',
      id: 1,
      method: 'getLatestLedger',
    }),
  });

  const data: RpcResponse<LatestLedger> = await response.json();

  if (data.error) {
    throw new Error(`RPC Error ${data.error.code}: ${data.error.message}`);
  }

  return data.result!;
}

Real-World Workflow: Contract Event Monitoring

Here's a practical example of using Claude Code to build an event monitoring system:

You: Help me build a script that monitors events from a
Soroban contract and logs them

Claude Code can generate a complete solution:

const CONTRACT_ID = 'CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC';

async function pollEvents(startLedger) {
  let cursor = startLedger;

  while (true) {
    const response = await fetch('https://rpc.lumenquery.io', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'X-API-Key': process.env.LUMENQUERY_API_KEY,
      },
      body: JSON.stringify({
        jsonrpc: '2.0',
        id: 1,
        method: 'getEvents',
        params: {
          startLedger: cursor,
          filters: [{
            type: 'contract',
            contractIds: [CONTRACT_ID],
          }],
          pagination: { limit: 100 },
        },
      }),
    });

    const { result } = await response.json();

    for (const event of result.events) {
      console.log('Event:', event.type, event.topic, event.value);
    }

    cursor = result.latestLedger;
    await new Promise(r => setTimeout(r, 5000)); // Poll every 5s
  }
}

Best Practices

1. Use Environment Variables

Never hardcode API keys. Claude Code can help you set up proper configuration:

You: Help me set up a config file for my RPC endpoints

2. Implement Retry Logic

Ask Claude Code to add resilience to your code:

You: Add exponential backoff retry logic to this RPC call

3. Validate Before Submitting

Always simulate transactions before sending:

You: Create a wrapper that simulates then submits transactions

4. Monitor Rate Limits

Claude Code can help you implement rate limiting:

You: Add rate limiting to stay within 60 requests per minute

Combining with LumenQuery

LumenQuery provides both Horizon REST API and Soroban RPC through a unified authentication layer. Claude Code makes it easy to work with both:

You: Get an account's XLM balance from Horizon, then check
their contract interactions via Soroban RPC

This kind of cross-API workflow becomes trivial with AI assistance.

Conclusion

Claude Code transforms how developers work with JSON-RPC APIs. Instead of memorizing method signatures and parameter formats, you can focus on what you're building while Claude Code handles the details.

For Stellar developers using LumenQuery's Soroban RPC, this means faster development cycles, fewer errors, and more time spent on application logic rather than API mechanics.

*Ready to supercharge your Soroban development? Sign up for LumenQuery and get 10,000 free API requests per month.*