Transaction Broadcast · SolanaLand first.
Earn the spread.
Every transaction you send moves prices and that movement is worth real SOL. Fast captures the resulting arbitrage and routes it back to your wallet as a cashback.
"cashbackAddress": "YourSolanaAddress"+ cashbackcurrent slot
298 472 841
next slot
298 472 842
How it worksSubmit to confirmed, same slot.
Submit your raw transaction
Send your Base58 or Base64 encoded transaction to fast.circular.fi/transactions via a standard JSON-RPC POST. Include your API key in the x-api-key header.
Instant network propagation
Fast pushes your transaction through the broadest possible set of nodes simultaneously. The goal is simple: reach as many validators as possible before the current slot boundary.
Land in the current slot
Your transaction lands in the slot that's already open, not the next one. For snipers, liquidators, and time-sensitive strategies, that single slot is the difference between winning and missing.
FeaturesBuilt for 0-slot landing.
Current slot, not next
Most transactions miss the current slot and land in the next one. Fast reaches validators before the slot boundary closes, giving your transaction the best possible chance of landing immediately.
Lands in current slot
0-slot delay
Queued for next slot
~400ms behind
Front-running protection
One flag to control how your transaction propagates.
falseMAXIMUM REACHtrueSTEALTH MODEGlobal infrastructure
Nodes distributed worldwide minimize the physical distance between your request and the nearest validator. Every millisecond counts.
Drop-in JSON-RPC
Same sendTransaction format as any Solana RPC. Swap the URL, add your API key header. Nothing else changes in your code.
Base58 or Base64
Send your transaction in either encoding. No serialization changes needed, whatever your wallet or SDK already produces.
One endpoint.
Up and running in minutes.
Fast uses the standard JSON-RPC sendTransaction format. If you already talk to a Solana RPC, switching to Fast is a one-line change.
POST fast.circular.fi/transactionsx-api-key headerJSON-RPC 2.0 · sendTransactioncurl -X POST https://fast.circular.fi/transactions \
-H "Content-Type: application/json" \
-H "x-api-key: YOUR_API_KEY" \
-d '{
"jsonrpc": "2.0",
"id": 1,
"method": "sendTransaction",
"params": [
"<BASE58_OR_BASE64_TX>",
{
"frontRunningProtection": false
}
]
}'
The same endpoint, any throughput.
All plans use the same URL and the same JSON-RPC format. Only your throughput ceiling changes.
Free
requests / second
Get started with no commitment. Great for testing and low-volume strategies.
Searcher
requests / second
For active traders who need consistent throughput without interruption.
Startup
Most popularrequests / second
High-frequency bots and production workloads that can't afford to be throttled.
Pro
Max performancerequests / second
Full access with priority routing and dedicated support for serious teams.
Need more credits or a higher limit?
Upgrade your plan on the Circular dashboard, no API change required.
View plans →