Amazon QLDB

Amazon Quantum Ledger Database (QLDB) is a non-relational database as a service (DBaaS) designed for AWS customers who want to maintain a verifiable history of data changes in an application they own. Using Amazon QLDB, an organization can ensure their application's change history cannot be viewed, altered or deleted.

Amazon QLDB can be used to store data such as credit and debit transactions in an application to create a permanent and complete financial transaction history. Amazon QLDB may be useful for organizations looking to implement blockchain technologies and can be used in finance, manufacturing, insurance, HR, payroll as well as retail fields. For example, a bank that needs to keep a centralized ledger that can record changes to transactions may want to consider using Amazon QLDB.

Amazon QLDB uses a transaction log, called a journal, which keeps track of each data change to an application. Additionally, QLDB will cryptographically maintain a complete history of changes over time.


Features of Amazon QLDB include:

  • The ability to scale up or down as needed.
  • An append-only journal, which is an immutable transaction log that stores an entry of every data change.
  • A summary of an application's change history, including transaction histories.
  • A document-oriented data model that shows how data is processed and stored in a database.
  • Serverless architecture, which means users do not have to worry about provision capacity or server configurations.
  • Monitoring, which is provided by Amazon CloudWatch. Users can monitor read/write events and storage volume, for example.


Similar to other AWS products, QLDB has a pay only for what you use model. Users are billed for read/write IO requests, data transfer, journal storage and indexed storage. Billing for read and write IO requests are based in millions of requests. Storage is billed in gigabytes a month. Data transfers across AWS reigns are billed in a varying tier from 1 GB a month ($0.00 per GB) to over 150 TBs a month ($0.05 per GB); this price is charged on both in and out data transfers. However, there is no charge for data transfers between services within the same AWS region.

This was last updated in May 2019

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