solana-proxy/docs/solana-free-websocket-providers.md

Free Solana WebSocket Providers

1. Alchemy

• Endpoint: wss://solana-mainnet.g.alchemy.com/v2/YOUR_API_KEY
• Free Tier Limits:
  • 300M Compute Units (CUs) monthly (~12M transactions)
  • 10 concurrent requests per WebSocket connection on free tier
  • 20,000 WebSocket connections per API Key limit
  • 1,000 parallel WebSocket subscriptions per connection
• Authentication: API key required (free signup)
• Pros:
  • Large monthly CU allocation
  • Professional infrastructure
  • 99.9% uptime SLA
  • Additional features (Smart Wallets, Webhooks)
• Cons:
  • Severe concurrent request limit on free tier (only 10)
  • Some users report issues with Solana WebSocket implementation
  • Requires registration

2. PublicNode

• Endpoint: wss://solana-rpc.publicnode.com
• Limits: None specified (completely free)
• Authentication: None required
• Pros:
  • No registration needed
  • No API keys
  • Privacy-focused
  • Simple to get started
• Cons:
  • No SLA or uptime guarantees
  • May have undocumented rate limits
  • No support

2. Helius

• Endpoint: wss://mainnet.helius-rpc.com/?api-key=YOUR_API_KEY
• Free Tier Limits:
  • 1M credits per month
  • 10 requests per second
  • Standard WebSockets included
• Authentication: API key required (free signup)
• Pros:
  • Reliable infrastructure
  • Community support
  • Additional APIs available (NFT, Token APIs)
  • Clear rate limits
• Cons:
  • Limited credits (1M/month)
  • Enhanced WebSockets only on paid tiers
  • Requires registration

4. QuickNode

• Endpoint: wss://YOUR_ENDPOINT_NAME.quiknode.pro/YOUR_TOKEN/
• Free Tier Limits:
  • 10M credits per month
  • WebSocket responses cost 50 credits each
  • ~200,000 WebSocket responses per month
• Authentication: Endpoint URL with token
• Billing Model: Pay per response, not per subscription
• Pros:
  • Generous credit allocation
  • Professional infrastructure
  • Good documentation
  • Multiple solutions (WebSockets, Streams, gRPC)
• Cons:
  • Credit-based billing for responses
  • Advanced features require paid plans
  • Must track response usage

4. Solana Public RPC

• Endpoint: wss://api.mainnet-beta.solana.com
• Limits: Subject to change without notice
• Authentication: None
• Pros:
  • Official Solana endpoint
  • No registration required
  • Completely free
• Cons:
  • NOT for production use
  • Aggressive rate limiting
  • Can block IPs without warning
  • No SLA or reliability guarantees
  • Poor performance under load

Recommendations

1. For Development/Testing: Use PublicNode or Solana Public RPC
2. For Small Projects: Helius (1M credits) or PublicNode
3. For Medium Projects: Alchemy (300M CUs but with concurrent limit) or QuickNode (10M credits)
4. For High-Volume HTTP with occasional WebSocket: Alchemy (best CU allocation)
5. For WebSocket-Heavy Applications: Avoid Alchemy free tier due to 10 concurrent request limit

Important Notes

• WebSocket subscriptions are stateful - you cannot easily switch providers mid-subscription
• Each provider may have slight differences in response format or timing
• Always implement reconnection logic for production applications
• Consider implementing client-side failover rather than load balancing for WebSockets
• Monitor your usage carefully, especially on QuickNode where responses consume credits