Instant Confirmations Are Redefining Blockchain Speed

Blockchains have always competed on confirmation speed, measuring how quickly users can be confident that a transaction has been accepted and is unlikely to be reverted. While Layer 2 networks have pushed confirmations below one second, even sub-second latency still breaks real-time experiences across DeFi, payments, and gaming.

Why Sub-Second Latency Still Isn’t Enough

In latency-sensitive environments like trading, even a 500ms delay can introduce real risk. Market makers quoting prices must wait for confirmation to know whether an order is still active. During that short window, traders can exploit outdated prices, forcing market makers to widen spreads. Wider spreads reduce liquidity and make markets less efficient for everyone.

Lower Inclusion Latency Enables Tighter Markets

As inclusion latency drops, the risk window shrinks dramatically. This allows market makers to keep spreads tight and react instantly to market changes, improving efficiency and liquidity across on-chain markets.

Etherlink Introduces Sub-50ms Instant Confirmations

With Instant Confirmations on Etherlink, users no longer wait for the next block to be produced. Instead, they receive a transaction receipt as soon as the sequencer commits to including the transaction in the next block. This reduces confirmation latency by ten times, from roughly 500ms to under 50ms, making on-chain interactions feel truly instant.

How Instant Confirmations Work on Etherlink

Instant Confirmations provide assurance that a transaction will be included in the next block within milliseconds. Etherlink nodes notify users immediately after the sequencer commits to inclusion, rather than waiting for block production.

Transaction Receipts Before Block Creation

Once the sequencer commits to inclusion, Etherlink nodes execute the transaction and return a full receipt containing gas usage, logs, execution status, and the transaction hash. Because the block has not yet been created, the block hash is unavailable, but this is sufficient for most applications where inclusion certainty matters more than final block confirmation.

Streaming Confirmations in Near Real Time

Transaction receipts can be streamed in near real time using new WebSocket subscriptions. This allows applications to observe and react to Instant Confirmations across the network as they happen, enabling real-time logic without polling.

Instant Confirmations Unlock New On-Chain Possibilities

Removing the gap between execution and confirmation opens the door to entirely new classes of applications where every millisecond matters.

DeFi Traders and Market Makers Benefit From Faster Feedback

For market makers, sub-50ms confirmations enable tighter spreads and faster reactions to volatility. Instant Confirmations also make it possible to observe transactions executing across the chain in near real time, unlocking faster arbitrage, quicker liquidity responses, and dynamic strategy adjustments based on live on-chain activity.

Real-Time Gaming Finally Feels Native On-Chain

Games and interactive applications require immediate feedback to maintain immersion. Waiting hundreds of milliseconds for confirmation breaks the experience. Instant Confirmations enable real-time gameplay with on-chain state, immediate inventory updates, responsive user interfaces, and multiplayer interactions that no longer feel laggy.

Agentic and Programmable Payment Systems Go Real Time

Instant Confirmations are especially powerful for agent-to-agent payment systems. Sequencer commitments allow programmable payment flows to react immediately, enabling machine-to-machine payments, dynamic pricing models, usage-based billing, and cross-border payment flows that trigger follow-up actions the moment execution occurs.

A Better Developer Experience for Real-Time Apps

Beyond end users, Instant Confirmations significantly improve the developer experience. Applications can respond immediately through WebSocket subscriptions, chain dependent transactions without waiting for blocks, debug faster with instant execution feedback, and build live dashboards that update as transactions execute.

How Etherlink Differs From Flashblocks and Other L2s

On OP Stack-based L2s like Base or Unichain, Flashblocks stream partial execution every few hundred milliseconds based on gas auctions. These confirmations are optimistic and derived from in-progress blocks, meaning transactions can still be reordered or changed before finalization.

Etherlink’s First-Come-First-Served Approach

Etherlink takes a fundamentally different path. Transactions are set for inclusion immediately on a strict first-come-first-served basis, subject to block capacity. Once included, transactions are streamed so receipts can be computed ahead of block creation, without relying on optimistic assumptions.

Lower Overhead and Cleaner Architecture

Unlike Flashblocks, Instant Confirmations do not require the sequencer to compute additional metadata during block creation. The sequencer focuses solely on ordering and committing transactions, while execution is handled by Etherlink nodes, resulting in a more efficient and scalable design.

Understanding Security and Finality

Instant Confirmations reduce latency but do not alter Etherlink’s finality model. As a rollup, Etherlink achieves finality when blocks are published and confirmed on Tezos Layer 1.

Execution Confirmation vs Block Confirmation

When a transaction is submitted using eth_sendRawTransactionSync with a pending flag, Etherlink returns a receipt as soon as the sequencer commits to inclusion and the transaction is executed. This provides synchronous confirmation from the application’s perspective, assuming trust in the sequencer’s commitment.

Stronger Assurance With Block Inclusion

For applications requiring higher certainty, users can wait for block confirmation, which takes around 500ms on Etherlink. This provides stronger guarantees while remaining well below one second.

What Happens if the Sequencer Stops

If the sequencer halts after execution but before block production, the transaction will not be settled and must be resubmitted once the sequencer restarts. This tradeoff is inherent to execution-first confirmation models.

Instant Confirmations Are Live in Experimental Mode

Instant Confirmations are currently experimental, with performance and reliability actively monitored as early adopters begin building and testing real-time applications.

How to Start Using Instant Confirmations

Developers can opt in by calling eth_sendRawTransactionSync from an Etherlink RPC node. The method returns an instant receipt containing execution details, excluding the block hash since the block does not yet exist.

WebSocket Subscriptions for Real-Time Apps

Applications can subscribe to custom WebSocket events to receive Instant Confirmations as transactions are queued for inclusion. This enables real-time responsiveness across DeFi, gaming, and payment systems.

Network Latency Still Matters

While protocol-level latency is drastically reduced, total end-to-end latency still depends on physical distance to the sequencer. With Etherlink’s sequencer operating from Tokyo, applications co-located nearby can achieve near execution-time responsiveness.

Infrastructure Placement Becomes a Competitive Edge

Latency-sensitive applications such as trading bots, market makers, games, and agentic payment systems benefit from deploying infrastructure closer to the sequencer, minimizing round-trip delays.

Instant Confirmations Unlock a New On-Chain Era

By cutting confirmation latency from roughly 500ms to under 50ms, Etherlink enables an entirely new category of applications that were previously impractical. High-frequency trading, real-time games, and next-generation payment systems can now operate on-chain without sacrificing responsiveness.