Stream scheduled Solana transactions
Preconfirmations stream transactions the instant a validator's scheduler commits to executing them — earlier than shred delivery and confirmed-commitment streams.
Available on all paid plans
A filtered firehose, built for the fast path
Open a single preconfSubscribe WebSocket and stream scheduled transactions as compact binary frames, a fixed 18-byte header your decoder reads in nanoseconds.
- Lifecycle stage
- Scheduled txn
- Transport
- WebSocket
- Billing
- 10 credits/message; 300-credit minimum/subscription when a slot delivers ≥1 message
Preconfs are an early signal, not a guarantee
A preconfirmation means a validator's scheduler has committed to executing the transaction, but it has not yet landed onchain and could still fail or drop. Coverage scales with participating validator stake, so expect and account for gaps.
The earliest point in the transaction lifecycle
Latency increases from left to right. Preconfirmations tap the scheduled-transaction stage before shreds exist.
Subscribe once, react first
Open a subscription
Connect to the Helius Gatekeeper endpoint and send a single preconfSubscribe request. Filter by account, region, or status. Only stream what you care about.
Get the earliest signal
Notifications arrive as compact binary frames with the slot, transaction index, status, and full transaction as soon as the scheduler commits to executing them.
Pay per message
Slots with zero delivered messages cost zero credits. When a slot delivers at least one message, each subscription is billed the greater of 300 credits or 10 credits per delivered message.
{
"jsonrpc": "2.0",
"id": 1,
"method": "preconfSubscribe",
"params": [
{
"failed": false,
"regionInclude": ["ewr", "fra"],
"accountInclude": ["TARGET_WALLET_ADDRESS"],
"accountExclude": ["TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA"],
"accountRequired": ["11111111111111111111111111111111"]
}
]
}Open a subscription
Connect to the Helius Gatekeeper endpoint and send a single preconfSubscribe request. Filter by account, region, or status. Only stream what you care about.
Get the earliest signal
Notifications arrive as compact binary frames with the slot, transaction index, status, and full transaction as soon as the scheduler commits to executing them.
Pay per message
Slots with zero delivered messages cost zero credits. When a slot delivers at least one message, each subscription is billed the greater of 300 credits or 10 credits per delivered message.
{
"jsonrpc": "2.0",
"id": 1,
"method": "preconfSubscribe",
"params": [
{
"failed": false,
"regionInclude": ["ewr", "fra"],
"accountInclude": ["TARGET_WALLET_ADDRESS"],
"accountExclude": ["TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA"],
"accountRequired": ["11111111111111111111111111111111"]
}
]
}Who are preconfs for?
Prop AMMs & HFTs
React to onchain activity at the earliest possible moment to stay ahead of the book
Snipers
See new launches the instant they're scheduled, not after they're confirmed
Copy traders
Mirror a target wallet's trades the moment their transaction is scheduled
Liquidation bots
Detect liquidation opportunities faster than your competitors
Searchers
Use preconfs to act on order flow your competitors can't see
Earn revenue by sending preconfirmations
Any validator can join and earn revenue by sending preconfirmations to Helius. The more participating stake, the broader the coverage is for everyone.
Preconfirmations (Preconfs) stream transactions at the earliest point they can be observed: the moment a validator schedules them, before they are collected into entries and converted into shreds. This is the lowest-latency transaction signal Helius offers.
Yes, there are gaps in coverage. Preconfirmations are only available for transactions scheduled by validators that forward their stream to Helius. Coverage scales with the share of network stake currently sending to Helius, so the stream is not continuous. Your trading system should account for gaps in coverage.
Preconfirmations are streamed the moment a validator's scheduler commits to executing a transaction, before any block data leaves the leader. Preprocessed Transactions come one stage later: once the block has been shredded and propagated. Helius decodes the raw shreds and streams the signed transactions to you over WebSocket, up to 8ms before the processed commitment level. Preconfirmations and Preprocessed Transactions are available on all paid plans. See pricing for more details.
Helius Preconfirmations are available on all paid plans (Developer, Business, Professional, and Enterprise). Slots with zero delivered messages cost zero credits. When a slot delivers at least one message, each open preconfSubscribe subscription is billed the greater of 300 credits or 10 credits per delivered message. See Credits for details.
To get started, explore these resources:
Get the earliest signal on Solana
Subscribe to preconfs and react the moment txs are scheduled. Available on all paid plans.