How to Understand a Solana Transaction Before You Sign It
Decode and simulate Solana transactions before signing. Understand what you're approving, spot hidden fees, avoid scams. Offline-capable.
What transactions actually contain
A Solana transaction is a bundle of instructions. Each instruction calls a specific program with specific data and affects specific accounts. Your wallet simplifies this, but the details matter.
A swap transaction might contain: an instruction to transfer SOL from your wallet to the DEX, an instruction for the DEX to execute the swap, an instruction to transfer new tokens to you, and instructions for protocol fees. All of this happens atomically, but 'everything' might include things you didn't expect.
Decoding in practice
Paste a transaction into the decoder—raw bytes, base58/64 encoded, or fetched by signature. The tool breaks down: programs called, what each instruction does in human-readable terms, which accounts the transaction reads or writes, who needs to sign, and the complete fee structure.
Beyond static decoding, the tool can simulate transactions against current blockchain state, showing you balance changes, token amounts, new accounts created, and accounts closed—all before anything is committed.
Red flags to watch for
Unknown programs warrant scrutiny. Unusual token approvals where delegate authority is granted to addresses you don't control—this is how 'approve and drain' attacks work. Hidden fees beyond what you expected. Account closures happening unexpectedly. Multiple signers required when you don't understand why.
Someone shared a 'claim' link or 'airdrop' transaction? Decode it before signing to see if it's actually draining your wallet instead.
Integration with your workflow
The decoder is for understanding, not signing. Get a transaction to sign from a DApp or protocol. Before signing, paste it into the decoder. Review the breakdown and simulation. If everything looks correct, sign in your normal wallet. If something's wrong, reject and investigate.
The decoder works offline for analyzing transaction data you already have. This is useful for air-gapped security review. Simulation requires network access to fetch current state.
Related product: PTT Transaction Lens — $9.99