Solvers
In the Nexus chain abstraction protocol, solvers are actors that facilitate cross-chain transactions by supplying liquidity on the destination chain.
When a user signs and authorizes an intent, a solver verifies the deposited into the Nexus contracts and instantly provides the liquidity on the destination chain.
Currently, Avail runs the solvers for Nexus. But the solver network will be progressively decentralized in time. In an optimal decentralized setup, multiple solvers compete to fulfill published intents, and may or may not charge a fee.
The protocol periodically settles funds with solvers who have successfully completed user intents, using tokens escrowed from the supported source chains once the “fill” action is verified.
To Fill here means, the action of the solver providing the liquidity to the user, basically “filling” the intent request for funds.