How to Build an Intent-Based DEX Aggregator With Solver and Filler Networks

• Capital allocation engine
• Inventory manager
• Gas estimator
• Profitability calculator
• Order watcher
• Transaction builder
• Executor contracts
• Private transaction submission
• Failure/retry management

UniswapX currently exposes open orders for fillers and requires them to determine which orders are profitable before submitting execution transactions. Its documentation also recommends private transaction infrastructure for competing fills because valid orders can attract competing execution attempts.

This makes the filler network an important competitive moat for a DEX Aggregator Development Company.

5. Settlement and Executor Contracts

The smart-contract layer should enforce the user's signed constraints.

A typical settlement flow is:

Intent → Solver bids → Winning solution → Filler execution → Contract validation → Token settlement

The settlement contract should verify:

• Authorized order
• Signature
• Nonce
• Deadline
• Minimum output
• Token amounts
• Recipient
• Solver/filler permissions where applicable
• Replay protection

The contract should never depend on the solver behaving honestly. The solver proposes; the settlement layer enforces.

6. MEV Protection

Intent-based architecture does not automatically eliminate MEV.