solana-transaction-safety

Transaction Submission

• ALWAYS submit transactions via Helius Sender endpoints — never raw sendTransaction to standard RPC
• ALWAYS include skipPreflight: true and maxRetries: 0 when using Sender
• ALWAYS include a Jito tip instruction (minimum 0.0002 SOL) for dual routing
• ALWAYS include ComputeBudgetProgram.setComputeUnitPrice — use getPriorityFeeEstimate MCP tool, never hardcode fees
• ALWAYS include ComputeBudgetProgram.setComputeUnitLimit — simulate first to get actual CU usage, add 10% margin; never leave the default 200,000 CU limit
• Instruction ordering: CU limit first, CU price second, your instructions, Jito tip last

Browser Safety

• From the browser, use the HTTPS Sender endpoint: https://sender.helius-rpc.com/fast
• NEVER use regional HTTP Sender endpoints from the browser — CORS preflight will fail
• For WebSocket data, use a server relay — never open Helius WebSockets directly from the browser (API key exposed in URL)

Commitment Levels

• Use confirmed by default
• Use finalized for critical operations that can wait seconds for confirmation
• Never rely on processed for anything important

Phantom Wallet Signing

• For extension wallets ("injected" provider): use signTransaction then submit via Helius Sender
• For embedded wallets ("google", "apple" providers): use signAndSendTransaction — signTransaction is NOT supported
• NEVER auto-approve transactions — each must be explicitly approved by the user
• ALWAYS handle user rejection gracefully — this is not an error to retry