FAQ

Authentication & Access

• How do I get an API key for the Avalanche C-Chain? Sign up at TheRPC.io, open the Dashboard, go to API Keys, and generate one. Append it to https://avalanche.therpc.io/YOUR_API_KEY and send it in the Authorization header.
• Can I create multiple API keys? Yes. Multiple keys let you isolate environments and apps — for example a separate key for local development, staging, and production, or one per service — so you can track usage and revoke any single key without disrupting the rest.
• What if a key is compromised? Revoke it immediately from the dashboard, then generate a new one and update your environment configuration. Revoking takes effect right away, cutting off any leaked key.

API Usage

• HTTP or WebSocket? Use the HTTP endpoint for single, stateless requests like reading an AVAX balance or sending a transaction. Use the WebSocket endpoint when you need real-time subscriptions on the C-Chain — streaming new blocks or event logs via eth_subscribe instead of polling.
• How do I handle rate limits? Catch the rate-limit error and retry with exponential backoff. If you hit limits regularly, consider upgrading your plan for a higher quota.
• What timeouts should I use? A reasonable default is a 30-second timeout for HTTP requests, a 60-second WebSocket ping/pong keep-alive, and a 30-second timeout for subscription operations.

Error Handling

The Avalanche C-Chain API uses the standard JSON-RPC error codes, summarized in the table below: -32700 for a parse error, -32600 for an invalid request, -32601 for a method that was not found, -32602 for invalid params, -32603 for an internal error, and the -32000 to -32099 range for server errors. Four habits make error handling robust: always check the error field before using a result, retry transient failures with exponential backoff, log the full error details for debugging, and set sensible timeouts so a slow call never hangs your application.

Common Error Response

1{
2  "jsonrpc": "2.0",
3  "error": {
4    "code": -32601,
5    "message": "Method not found"
6  },
7  "id": 1
8}

Standard JSON-RPC Error Codes

Technical Questions

• How do I track a pending transaction? Poll eth_getTransactionReceipt with the transaction hash until a receipt appears, or subscribe to updates in real time with eth_subscribe over WebSocket. On the C-Chain's fast finality, receipts typically arrive within a couple of seconds.
• How do I keep transactions in order? Sequence them by nonce. Fetch the current nonce with eth_getTransactionCount, increment it per transaction, and use an application-level queue so you never send two transactions with the same nonce.
• How do I handle chain reorganizations? Wait for a few confirmations by watching eth_blockNumber advance, listen to newHeads via eth_subscribe to react to new blocks, and verify finality by re-reading the block with eth_getBlockByNumber. Avalanche's Snowman consensus reaches finality quickly, but waiting for confirmations is still good practice for high-value operations.

Transaction Tracking Example

1// Example of transaction tracking
2const receipt = await web3.eth.getTransactionReceipt(txHash);
3if (receipt) {
4  console.log(`Transaction confirmed in block ${receipt.blockNumber}`);
5}

Performance

• How do I optimize API usage on the C-Chain? Batch multiple JSON-RPC calls into a single request, switch from polling to WebSocket subscriptions for real-time data, cache responses for slowly-changing values like block data or contract code, and tune your polling intervals to the chain's one-to-two-second block cadence rather than hammering the endpoint.
• What about high-throughput workloads? Use connection pooling to reuse sockets, queue requests so you stay under your rate limit, monitor your remaining quota from the response headers, and consider a dedicated plan with higher limits if you are running heavy indexing or trading infrastructure.

Network Specific

• How do I switch between networks? Just change the endpoint URL. The same API key and the same JSON-RPC request format work across every network TheRPC hosts, so moving from the Avalanche C-Chain to another chain is a one-line change. Confirm which network you reached with net_version.
• Does my code need to change per network? No — the code is identical; only the endpoint differs. The Avalanche C-Chain mainnet uses chain ID 43114 (0xa86a in hex), which you can verify at runtime with eth_chainId before signing transactions.

Development & Integration

• Which Web3 libraries work with the C-Chain? Because the Avalanche C-Chain is fully EVM-compatible, standard Ethereum tooling works unchanged: web3.js or ethers.js for JavaScript and TypeScript, web3.py for Python, and web3j for Java. See Quick Start for setup in each language.
• How should I test my integration? Start against the Avalanche testnet (Fuji) with a test API key before touching mainnet, build in error handling from the start, validate connectivity with a simple eth_blockNumber call, and monitor latency and quota as you scale up.