Achieving Zero-Slot Execution with Sender and LaserStream

0xIchigo

Developer Experience Engineer

13 min read

Sep 11, 2025

Introduction

Everyone wants their transactions to land as fast as possible. However, as Solana trading infrastructure becomes more sophisticated and on-chain markets mature, simply sending a transaction and hoping for the best doesn’t cut it anymore—congestion, competition, and network quirks turn “fast” into “frustratingly unreliable.”

The goal is straightforward: when a signal hits—a price crosses a certain threshold, an account updates, a program is invoked—a transaction reacting to that signal should land in the same slot.

That’s the essence of zero-slot execution, where detection and submission happen so seamlessly that opportunities are captured before they vanish in milliseconds.

In practice, this is increasingly difficult to achieve, requiring ultra-low-latency signal ingestion and reliable, deterministic delivery.

Helius provides both.

By combining LaserStream for lightning-fast event detection with Sender for optimized transaction submission, Helius delivers an end-to-end pipeline purpose-built for zero-slot execution.

LaserStream and Sender: A Unified Workflow

Sender complements LaserStream to create a seamless, end-to-end pipeline for responsive trading workflows on Solana. In practice,

1. Use LaserStream to Listen For Signals: Shred-level ingestion and advanced filtering deliver real-time on-chain events faster than any other pipeline.
2. Use Helius Sender to React to Signals: Transactions are dispatched via SWQoS and Jito simultaneously, with global routing and validator-aware delivery to maximize inclusion and minimize latency.
3. Profit: Together, these services make securing profitable opportunities achievable in practice, not just theory.

With Helius, developers get a vertically integrated stack purpose-built for speed and reliability:

• No need to stitch together third-party RPCs, relays, or homegrown infrastructure.
• Global routing, automatic retries, and validator-aware delivery are built in.

Finding the Right Signal

Arbitrages and liquidations can vanish in milliseconds on Solana. Detecting the right on-chain signal in a timely manner is of paramount importance. Here, a “signal” refers to any real-time event, such as a token transfer, account update, or program invocation, which presents a tradeable opportunity. Without ultra-low-latency ingestion, edges evaporate before they can be acted upon, making reliable, high-speed data streaming essential.

LaserStream is Helius’ next-generation Solana data streaming service, which combines the speed of shred-level ingestion with the reliability and reach of a globally distributed service, without the cost or operational headaches of running multiple dedicated nodes.

Optimizing Transaction Sending Workflows

Transaction inclusion is a multi-variable optimization problem that requires a deep understanding of multiple areas of Solana’s architecture. Factors such as arrival time, simulation success, account lock conflicts, associated transaction fees, and priority all interplay to determine when a given transaction executes on-chain.

To effectively land a transaction on Solana today, a developer needs to:

Use Staked Connections

Staked connections leverage Solana’s Stake-Weighted Quality of Service (SWQoS), prioritizing traffic from staked validators and paired RPCs for better leader reachability and propagation speed.

Add Dynamic Priority Fees

Priority fees help boost a transaction’s position in the leader’s scheduler in the Banking Stage.

Optimize CU Usage

Compute Units (CUs) quantify a transaction’s computational demand. Exceeding the requested budget triggers execution failures, while over-requesting inflates priority costs.

Use the Proper Commitment Level For Fetching Data

Commitment levels determine the confirmation depth for fetched data like blockhashes.

Skip Preflight Checks

Preflight checks simulate a transaction on the RPC node prior to submission, verifying signatures, instructions, and execution to catch errors early.

Setting the maxRetries Parameter to Zero

The maxRetries parameter in the sendTransaction method enables automatic resends on the RPC side in the event of failures.

Consider Using Jito

Jito tips enable off-chain bundles via MEV auctions, ensuring guaranteed transaction inclusion and ordering for partial blocks.

Sender

Sender is Helius’s ultra-low-latency transaction sending service that leverages SWQoS and Jito’s off-chain auctions for MEV-optimized inclusion.

How Sender Works

Sender processes transactions via a simple JSON-RPC POST request, where the transaction is serialized to base64 and submitted to one of its endpoints.

How to Get Started

Working With LaserStream

LaserStream offers the same developer experience as working with gRPC. Simply change the endpoint and API key to point to LaserStream.

Working With Sender

Helius Sender is available to all users and doesn’t consume any additional credits—no paid plans or special access required.

Working With LaserStream and Sender

The real power of Helius comes from combining LaserStream and Sender into a single workflow.

Why Helius

Helius stands out as the premier choice for optimizing transaction workflows on Solana, thanks to our position as the network’s largest validator by stake. Staked bandwidth is therefore not an issue for us, effectively eliminating any bottlenecks or failure cases related to transaction deprioritization or packet drops during congestion.

Faster

LaserStream reduces latency and uncertainty. The sooner a signal arrives, the more predictable the outcomes become. Combined with Sender, transactions sent in reaction to a signal enable greater operational confidence.