Atto (cryptocurrency)

Atto is a feeless cryptocurrency based on a parallel account-chain architecture with block timestamps, sequence numbers and standard SHA-512 cryptography, with the original node implementation being written in Kotlin.

Atto's technology facilitates true micropayments, with sub-second network-wide confirmation for transactions of any size.

Felipe Rotilho started development on the Atto node on January 6, 2022. On November 22, 2024, the first version of the node was released, with the genesis transaction taking place on the next day.

In May through August 2025, the Atto team on Folding@home was ranked in first place for earning the most credit in those months.

On August 20, 2025, after its second exchange listing, Atto's folding reward distribution system was modified to take large swings in price into account, which led to a 98% reduction of the fixed reward rate.

An Atto node either plays the role of a historical node, which is responsible for maintaining a copy of all confirmed transactions in the ledger, or a voting node, which engages in consensus. Nodes communicate their roles with their peers, allowing voting nodes to filter election traffic from being sent to historical nodes, which reduces the bandwidth requirements for a historical node.

Atto uses a parallel account-chain ledger where each account maintains an independent sequence of blocks, with each block's position in the ledger characterized by the account that it belongs to and its sequence number ("height") within that account's chain.

By having a height associated with each block, upon receiving a transaction, a node can insert the block into the appropriate account-chain without performing a database lookup to determine the correct position in the sequence. This is in contrast to directed acyclic graph (DAG)-based ledgers that rely on a "previous transaction" association when inserting a transaction into an account-chain.

Each block contains a timestamp, giving nodes information about how recent a transaction was published for use during traffic prioritization, limiting the precomputation of work and allowing for time-based decisions such as an automated difficulty increase following Moore's Law.

In order to allow for the possibility to validate an account's transactions without traversing the entire ledger, each account keeps track of its received funds in the form of receive transactions, with each pointing to its respective send transaction within the sending account's chain.

Atto transactions are signed using standard Ed25519 signatures that follow the BIP32 convention (which uses SHA-512 as the hash function) used by Bitcoin and Ledger signers.