How to see pending transactions on Solana
On Ethereum, pending transactions wait in a public mempool that anyone can watch. Solana has no such mempool. This guide explains where pending Solana transactions actually are and how you can see them before they execute.
Where pending transactions go
Wallets, dApps and bots send transactions to an RPC node or a sending service, which forwards them straight to the TPU (Transaction Processing Unit) of the current leader and the next leaders in the schedule. There is no shared waiting area: a pending transaction exists only in the TPU queues of the validators it was sent to, until a leader executes it.
Jito ran a mempool for bundle searchers, but suspended it in March 2024. Since then there has been no public way to watch pending transactions.
Your options
| Source | What you see | When |
|---|---|---|
| RPC and WebSocket subscriptions | Executed transactions | After replay |
| Shreds | Transactions the leader has already put into the block | During block production, before replay |
| Your own validator | Transactions sent to your validator | Around your own leader slots, which takes significant stake |
| Private orderflow from a validator network | Transactions arriving at the TPU of the validators in that network | Before execution |
Only the last two show transactions before they execute. Running your own validator only pays off with significant stake, so most searchers use orderflow from a validator network.
Streaming pending transactions with Private Orderflow
Private Orderflow streams transactions as they arrive at the TPU of validators in our network, before execution and block inclusion. Our relayer does not hold or delay them.
- gRPC push, compatible with Jito's protocol: your server acts as the block engine, our relayer connects to it and pushes
PacketBatchUpdatemessages. You filter on our side by the accounts and programs of interest your server sends. - WebSocket: a stream you filter on your side.
Each message carries the signed transaction, so you can decode its instructions, simulate its effect on the state you track and react. See Private Orderflow for the message formats and code examples.
What coverage to expect
The stream is never a complete mempool. You see the transactions that reach validators in our network, and your coverage grows with the stake pool in your offer. To estimate your share, compare the signatures you receive with the transactions that later land in blocks, as described in Private Orderflow.
Next steps
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