Mirror Nodes

Store history and cost-effectively query data

Mirror nodes act as powerful tools within the Hedera Network, offering a means to store and access historical data from the public ledger cost-effectively and efficiently. These nodes contribute to resource optimization by minimizing the utilization of the Hedera Network's resources. The services provided by mirror nodes extend to all currently available Hedera Network services and can retrieve:

• Transactions and Records: Mirror nodes store all transaction data that occurs within the network, along with their accompanying records. This information can be queried for audit purposes, analytics, or network monitoring.

• Event Files: These are files created by consensus nodes that capture all the events occurring on the Hedera Network. Mirror nodes store these files and make them available for analysis and review.

• Balance Files: Balance files provide a snapshot of the state of all accounts within the Hedera Network at the time of their creation. These files, which are stored and made accessible by mirror nodes, include details such as account balances and account status information.

By offering a way to access this information, mirror nodes play a crucial role in maintaining transparency and accessibility within the Hedera Network.

Understanding Mirror Nodes

Hedera Mirror Nodes receive data from Hedera Network consensus nodes, either mainnet or testnet, and provide a more effective means to perform:

• Queries: Mirror nodes allow for comprehensive and efficient querying of historical transaction data and records from the network.

• Analytics: By maintaining historical data from the network, mirror nodes support detailed analytics, providing insights into network performance, transaction patterns, and trends.

• Audit Support: Mirror nodes store all transactions and records, enabling complete audits of network activity, which is crucial for transparency and accountability.

• Monitoring: Through the continuous intake and storage of network data, mirror nodes support real-time network monitoring, ensuring timely detection and response to network events.

Although Mirror Nodes receive data from consensus nodes, they do not participate in consensus formation. The trust in Hedera is established by the consensus reached by the consensus nodes and is then transferred to the mirror nodes using signatures, chain of hashes, and state proofs.

How Mirror Nodes Work

Mirror nodes work by validating the signature files associated with the record, balance, and event files that consensus nodes upload to a cloud storage solution from the network.

As transactions reach consensus on the Hedera Network, either mainnet or testnet, Hedera consensus nodes add the transaction and its associated records to a record file. This file contains a sequence of ordered transactions and their respective records. After a specified time, a record file is closed, and a new one is created. This process repeats as the network continues to receive transactions.

Once a record file is closed, the consensus nodes generate a signature file, which includes a signature for the corresponding record file’s hash. Along with the consensus node's signature file, the record file also contains the hash of the preceding record file, allowing the validation of the former record file by comparing the hash of the previous record file.

Hedera consensus nodes push new record files and signature files to the cloud storage provider – currently, AWS S3 and Google Cloud Storage are supported. Mirror nodes download these files, verify their signatures based on their hashes, and only after successful verification are these files processed and made accessible.

Hedera REST API and Mirror Node Deployment

Mirror nodes simplify initial deployments by eliminating the need to run a full Hedera node. This is accomplished by creating periodic files containing processed information, such as account balances or transaction records, which are validated by Hedera consensus nodes. The mirror node software reduces the processing burden by accepting pre-constructed files from the network, verifying these files, and populating a database.

To streamline access to this data, Hedera offers REST APIs, allowing effortless querying of a Mirror Node hosted by Hedera. For further details, refer to the Mirror Node REST API documentation.

For those interested in running a Hedera Mirror Node, the software can be downloaded and set up on a local machine. This allows users to connect to the appropriate cloud storage and store account balance files, record files, and event files. Please refer to the Run Your Own Mirror Node section for further information on getting started with this process.