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
// 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} — ${error.message}`);
}
return null;
}
}
NFT API Errors
| Error | Root Cause | Fix |
|---|
Empty ownedNfts | Address has no NFTs on this chain | Check correct network |
Missing image.cachedUrl | IPFS/Arweave gateway timeout | Use image.originalUrl fallback |
getNftsForContract empty | Contract not indexed | Wait for indexing; try refreshContract |
| Spam NFTs in results | No spam filter | Add excludeFilters: ['SPAM'] option |
getNftMetadataBatch fails | Batch too large | Limit to 100 tokens per batch |
Enhanced API Errors
| Error | Root Cause | Fix |
|---|
getAssetTransfers empty | Wrong category | Include all: EXTERNAL, ERC20, ERC721, ERC1155 |
getTokenBalances timeout | Too many tokens | Paginate or use specific contract addresses |
getTokenMetadata null fields | Token not verified | Handle null name/symbol gracefully |
| WebSocket disconnect | Idle timeout (5 min) | Implement auto-reconnect logic |
Network-Specific Issues
// Diagnostic function
async function diagnoseAlchemyIssue(alchemy: Alchemy): Promise<string[]> {
const issues: string[] = [];
try {
const blockNumber = await alchemy.core.getBlockNumber();
console.log(`Connected: block #${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: ${err.message}`);
}
return issues;
}
Quick Diagnostic
# Test Alchemy API directly
curl -s "https://eth-mainnet.g.alchemy.com/v2/${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
Next Steps
For collecting debug bundles, see alchemy-debug-bundle.
