# Why We Need CKB Open Transaction ## Metadata **Status**:: #x **Zettel**:: #zettel/permanent **Created**:: [[2022-09-22]] **Topic**:: [[♯ CKB Open Transaction]] **Parent**:: [[Describe the CKB Open Transaction Project]] ## Notes When many parties collaborate on constructing a CKB transaction, they have to exchange the partial transaction information. Open Transaction will act as the bridges between these parties that they can communicate with each other. Several participants have numerous combinations via composition, and the number rises extremely fast as the network grows. There are two scenarios that CKB Open Transaction will play an important role. The first is incremental transaction construction. One party works on an open transaction, changes it, and hands to the next participant. For example, the indexer collects input cells for a user; the dApp creates the unsigned transaction based on the inputs; and the hardware wallet finally signs the transaction. With Open Transaction, users can choose any service in each step. The second is transaction aggregation, which combines many matched open transactions into one CKB transaction. For example, if users want to exchange assets, they can publish the proposal as open transactions, and the third party can combine matched proposals to clear the transaction. Open Transaction also helps to work around the hot cell problem that multiple transactions want to use the cell as the input and only one will succeed. Without Open Transaction, users have to create and sign the transaction again and again on failures. Open Transaction will provide a feature that anyone can re-create the transaction by replacing the input cell without re-signing, so third parties can run services without user interactions.