Subblocks in Ergo
Reducing confirmation times from 2 minutes to 2 seconds with sub-blocks and ordering blocks.
TLDR
With the renaming and introduction of sub-blocks, Ergo now distinguishes between sub-blocks (also called input blocks) and full blocks (now called ordering blocks). This change reduces typical onchain confirmation times from about 2 minutes to roughly 2 seconds, achieving a 17× improvement in detecting transaction failures and transforming the current competitive mempool into a more cooperative environment.
What Are Sub-blocks and Ordering Blocks?
Sub-blocks (Input Blocks)
These are block candidates generated with a lower difficulty threshold than full blocks. They are produced approximately once per second and carry most transaction data. This allows transactions to propagate and confirm much faster.
Ordering Blocks
These are the traditional full blocks of Ergo's proof-of-work system, now renamed as ordering blocks. They are generated roughly every 2 minutes and maintain the overall consensus and security of the blockchain.
Note: The naming "input blocks" (or sub-blocks) and "ordering blocks" was proposed in detail in this document.
Enhanced User Experience
Rapid Onchain Confirmations
Everyday transactions—such as receiving tokens from DEX swaps or wallet-to-wallet transfers—can now be confirmed in approximately 2 seconds due to the introduction of sub-blocks. These input blocks are produced roughly every second and carry transaction data, allowing dApps and wallets to detect transaction inclusion almost instantly.
However, this does not change the overall 2-minute block time for ordering blocks, which are still required for final settlement and consensus. As a result, existing dApps that rely on ordering blocks for confirmation will continue to behave as before.
While some tools may treat sub-block inclusion as sufficient for faster user feedback, more security-sensitive applications—such as centralized exchanges or specific dApps handling large-value transactions—will still wait for a set number of ordering blocks to reduce the risk of chain reorganizations or 51% attacks.
Faster Failure Detection
Instead of waiting up to 6 minutes to detect a transaction failure, the new system detects failures in about 2 seconds—a 17× improvement in responsiveness.
A More Cooperative Mempool
The design shift transforms the mempool from a competitive (PvP) environment into a cooperative, multiplayer-like system, enhancing overall network responsiveness.
In a Nutshell
Ergo's renaming and introduction of sub-blocks (input blocks) paired with ordering blocks significantly improves transaction processing speed and reliability. These changes provide users with near-instant confirmations and faster failure detection, thereby offering a smoother and more efficient experience on the network.
For a deep dive into the technical details behind these changes, see the technical details.