Amazon Quantum Ledger Database (QLDB)

Fully managed ledger database that provides a transparent, immutable, and cryptographically verifiable transaction log. Owned by a central trusted authority.

Amazon QLDB is a fully managed ledger database that provides a transparent, immutable, and cryptographically verifiable transaction log ‎owned by a central trusted authority. Amazon QLDB tracks each and every application data change and maintains a complete and verifiable history of changes over time.

Ledgers are typically used to record a history of economic and financial activity in an organization. Many organizations build applications with ledger-like functionality because they want to maintain an accurate history of their applications' data, for example, tracking the history of credits and debits in banking transactions, verifying the data lineage of an insurance claim, or tracing movement of an item in a supply chain network. Ledger applications are often implemented using custom audit tables or audit trails created in relational databases. However, building audit functionality with relational databases is time-consuming and prone to human error. It requires custom development, and since relational databases are not inherently immutable, any unintended changes to the data are hard to track and verify. Alternatively, blockchain frameworks, such as Hyperledger Fabric and Ethereum, can also be used as a ledger. However, this adds complexity as you need to set-up an entire blockchain network with multiple nodes, manage its infrastructure, and require the nodes to validate each transaction before it can be added to the ledger.

Amazon QLDB is a new class of database that eliminates the need to engage in the complex development effort of building your own ledger-like applications. With QLDB, your data’s change history is immutable – it cannot be altered or deleted – and using cryptography, you can easily verify that there have been no unintended modifications to your application’s data. QLDB uses an immutable transactional log, known as a journal, that tracks each application data change and maintains a complete and verifiable history of changes over time. QLDB is easy to use because it provides developers with a familiar SQL-like API, a flexible document data model, and full support for transactions. QLDB is also serverless, so it automatically scales to support the demands of your application. There are no servers to manage and no read or write limits to configure. With QLDB, you only pay for what you use.

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Looking to build a blockchain application? Learn more about Amazon Managed Blockchain here.

Amazon QLDB benefits

Immutable and Transparent

Amazon QLDB uses a journal that tracks each application data change and maintains a complete and sequenced history of changes over time. Data on the journal cannot be deleted or modified. The full history of your database can be accessed and you can query and analyze the history to see how your data has changed over time.


Cryptographically Verifiable

With Amazon QLDB, you can trust that the history of changes to your application data is accurate. QLDB uses a cryptographic hash function (SHA-256) to generate a secure output file of your data’s change history, known as a digest. The digest acts as a proof of your data’s change history, allowing you to look back and validate the integrity of your data changes.

Highly Scalable

Amazon QLDB is highly scalable and can execute 2 – 3X as many transactions than ledgers in common blockchain frameworks. Blockchain frameworks are decentralized so to execute a transaction, they require a majority of members of the network to reach consensus on the validity of the transaction. On the other hand, QLDB has a centralized design, allowing its transactions to execute without the need for multi-party consensus.


With Amazon QLDB, you don’t have to worry about provisioning capacity or configuring read and write limits. You create a ledger, define your tables, and QLDB automatically scales to support the demands of your application. To help you gain a better understanding of the operational health of your database, QLDB also allows you to monitor operational metrics such as read-events, write-events, storage, etc.

Easy to Use

Amazon QLDB’s familiar database capabilities make it easy to use. QLDB’s SQL-like API allows you to query, manage and update your data using SQL operators. QLDB’s document-oriented data model is flexible, enabling you to easily store and process both structured and semi-structured data.

How it works


Use cases


Banks often need a centralized ledger-like application to keep track of critical data, such as credit and debit transactions across customer bank accounts. Instead of building a custom ledger which has complex auditing functionality, banks can use QLDB to easily store an accurate and complete record of all financial transactions.


Manufacturing companies often need to reconcile data between their supply chain systems to track the full manufacturing history of a product. A ledger database can be used to record the history of each transaction, and provide details of every individual batch of the product manufactured at a facility. In case of a product recall, manufacturers can use QLDB to easily trace the history of the entire production and distribution lifecycle of a product.


Insurance applications often need a way to better track the history of claim transactions. Instead of building complex auditing functionality using relational databases, insurance companies can use QLDB to accurately maintain the history of claims over their entire lifetime, and whenever a potential conflict arises, QLDB can also help cryptographically verify the integrity of the claims data (e.g., whether a claim was submitted accurately), making the application resilient against data entry errors and manipulation.

HR & Payroll

HR systems often have to track and maintain a record of an employee’s details such as payroll, bonus, benefits, performance history, and insurance. By implementing a system-of-record application using QLDB, customers can easily maintain a trusted and complete record of the digital history of their employees, in a single place.

Retail & Supply Chain

Retailers often need to access information on every stage of a product's supply chain, such as what location did the product come from, how many items of the product were shipped and to whom, who handled the shipment, etc. With QLDB, retail companies can look back and track the full history of inventory and supply chain transactions at every logistical stage of their products.



Healthdirect Australia is a national, government-owned, not-for-profit organization that has been helping Australians manage their health and wellbeing for over a decade.

“Healthdirect Australia operates in a heavily regulated industry, and it is critical that our compliance data is correct and auditable. With Amazon QLDB we look forward to having a complete and verifiable history of every change in our system, making it simple to audit when and how we arrived at our current state. Regulatory compliance is fact of life for healthcare companies, and Amazon QLDB enables us to easily track the controls we have in place and understand how they have changed over time.”

Bruce Haefele - General Manager, Technology, Healthdirect Australia


Smaato, one of the leading online ad exchanges in the world, sees over 20 billion bid requests/day pass through their exchange.

“All participants in the online advertising and real time bidding market segments are interested in transparency throughout the entire lifecycle of an online ad auction, from the initial auction, to the winning bid, and ultimately through to the final impression delivery and who it’s actually shown to. Since we act as a centralized point of trust in this value chain, we’re really excited about Amazon QLDB. It offers a scalable, immutable, and cryptographically verifiable ledger that would allow us to maintain a complete and auditable record of all our auctions. We’re looking forward to collaborating with AWS and the Amazon Quantum Ledger Database team to bring more transparency to our ecosystem.”

Ragnar Kruse - CEO, Smaato