Alchemy Common Errors

Overview

Troubleshooting guide for Alchemy SDK errors covering rate limits, RPC failures, invalid parameters, and network-specific issues.

Error Reference

Authentication & Rate Limits

| HTTP Code | Error | Root Cause | Fix | |-----------|-------|-----------|-----| | 401 | Unauthorized | Invalid or missing API key | Verify key in Alchemy Dashboard | | 403 | Forbidden | API key disabled or app deleted | Create new app in Dashboard | | 429 | Too Many Requests | Rate limit exceeded | Implement backoff; upgrade plan | | 429 | Compute Units exceeded | CU quota depleted | Check CU usage in Dashboard |

Alchemy Rate Limits by Plan

| Plan | Compute Units/sec | Throughput | |------|-------------------|------------| | Free | 330 CU/s | ~25 requests/s | | Growth | 660 CU/s | ~50 requests/s | | Scale | Custom | Custom |

RPC & Query Errors

typescript
// Common RPC error handler
import { Alchemy, Network } from 'alchemy-sdk';

async function safeAlchemyCall<T>(
  operation: () => Promise<T>,
  context: string
): Promise<T | null> {
  try {
    return await operation();
  } catch (error: any) {
    const code = error.code || error.response?.status;

    switch (code) {
      case -32602: // Invalid params
        console.error(`[${context}] Invalid parameters: ${error.message}`);
        console.error('Common causes: wrong address format, invalid block number, missing 0x prefix');
        break;

      case -32600: // Invalid request
        console.error(`[${context}] Malformed JSON-RPC request`);
        break;

      case -32601: // Method not found
        console.error(`[${context}] RPC method not available on this network`);
        console.error('Some Enhanced APIs are Ethereum-only');
        break;

      case -32000: // Server error
        console.error(`[${context}] Node server error — usually transient, retry`);
        break;

      case 429:
        const retryAfter = error.response?.headers?.['retry-after'] || 1;
        console.error(`[${context}] Rate limited — retry after ${retryAfter}s`);
        break;

      default:
        console.error(`[${context}] Unknown error: ${code} — ${error.message}`);
    }
    return null;
  }
}

NFT API Errors

| Error | Root Cause | Fix | |-------|-----------|-----| | Empty ownedNfts | Address has no NFTs on this chain | Check correct network | | Missing image.cachedUrl | IPFS/Arweave gateway timeout | Use image.originalUrl fallback | | getNftsForContract empty | Contract not indexed | Wait for indexing; try refreshContract | | Spam NFTs in results | No spam filter | Add excludeFilters: ['SPAM'] option | | getNftMetadataBatch fails | Batch too large | Limit to 100 tokens per batch |

Enhanced API Errors

| Error | Root Cause | Fix | |-------|-----------|-----| | getAssetTransfers empty | Wrong category | Include all: EXTERNAL, ERC20, ERC721, ERC1155 | | getTokenBalances timeout | Too many tokens | Paginate or use specific contract addresses | | getTokenMetadata null fields | Token not verified | Handle null name/symbol gracefully | | WebSocket disconnect | Idle timeout (5 min) | Implement auto-reconnect logic |

Network-Specific Issues

typescript
// Diagnostic function
async function diagnoseAlchemyIssue(alchemy: Alchemy): Promise<string[]> {
  const issues: string[] = [];

  try {
    const blockNumber = await alchemy.core.getBlockNumber();
    console.log(`Connected: block #${blockNumber}`);
  } catch (err: any) {
    if (err.message?.includes('apiKey')) issues.push('API key invalid or missing');
    else if (err.code === 'ECONNREFUSED') issues.push('Cannot reach Alchemy servers — check network');
    else issues.push(`Connection error: ${err.message}`);
  }

  return issues;
}

Quick Diagnostic

bash
# Test Alchemy API directly
curl -s "https://eth-mainnet.g.alchemy.com/v2/${ALCHEMY_API_KEY}" \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":0}' | jq .

# Check CU usage (requires auth token)
curl -s "https://dashboard.alchemy.com/api/stats" \
  -H "Authorization: Bearer ${ALCHEMY_AUTH_TOKEN}" | jq .

Output

• Error classified by type (auth, rate limit, RPC, network)
• Root cause identified with specific fix
• Diagnostic function for automated troubleshooting

Resources

• Alchemy Error Codes
• Alchemy Rate Limits
• JSON-RPC Error Codes

Next Steps

For collecting debug bundles, see alchemy-debug-bundle.