--- title: "Hedera Block Nodes in Private Preview" id: "15526" type: "post" slug: "hedera-block-nodes-in-private-preview" published_at: "2025-12-08T15:58:31+00:00" modified_at: "2026-09-08T10:08:13+00:00" url: "https://hedera.com/blog/hedera-block-nodes-in-private-preview/" markdown_url: "https://hedera.com/blog/hedera-block-nodes-in-private-preview.md" excerpt: "Block nodes - a new node type being launched in 2026 - will be the decentralized data lake of the Hedera network. In November 2025, the Hashgraph team deployed a private preview of council-operated Block Nodes in previewnet, testnet, and..." taxonomy_category: - "Uncategorized" taxonomy_post_tag: - "technical" --- [Skip to content](#content) blog # Hedera Block Nodes in Private Preview December 8, 2025 Nana Essilfie-Conduah Director of Software Engineering Hedera Hedera provides secure, scalable infrastructure for real-world decentralized applications in finance, AI, and sustainability, governed by global enterprises. #### **Private Preview Deployment and Timeline** Block Nodes—launching in 2026—will become the **decentralized, cost-efficient data lake of the Hedera network.** They will replace today’s large cloud bucket storage and enable faster, cheaper, and more flexible access to network data. Mirror nodes will be able to stream the unified HIP-1056 *Block Streams* format (which will fully replace the legacy *record file* format) directly from block nodes to obtain network data. **Mirror Node operators are directly affected.** To avoid data ingestion interruptions during this transition, Mirror Nodes **must upgrade** to a version that supports the new Block Streams format. Block Nodes will provide: - **Immediate streaming access to exported consensus network data** - **On demand retrieval** for both recent and historical block data - **Future support for filtered queries**, allowing operators and builders to request and store only the portions of block data they care about - **State services such as State Proofs** and state snapshots queries In November 2025, the Engineering team deployed a **private preview of council-operated Block Nodes** across previewnet, testnet, and mainnet. This major milestone begins network validation of **HIP-1056 Block Streams** and **HIP-1081 Block Nodes**. Today, these preview block nodes run **in parallel** with existing operations, which continue to rely on record files and full-history cloud buckets. As expected in an early preview some capabilities remain incomplete e.g. blocks are not yet signed with HIP-1200 hinTS threshold signature verification. Over the coming months, engineering teams will refine software, hardware recommendations, and deployment patterns. Access will be opened to community builders in Q1 2026, allowing Mirror Node operators to start testing integrations early in the previewnet and testnet environments. #### **Architectural Changes for Mirror Nodes** Under the future Block Node model: #### **1. Cloud buckets → Direct Block Node subscription** Mirror Nodes will **stop downloading record files** and instead: - **Subscribe directly to a Block Node** for live block items - Receive block data **as it is produced**, significantly reducing latency - Retrieve historical data from any Block Node without having to rely on centralized storage #### **2. Limited-history cloud buckets → Block Streams ingestion** Mirror Nodes with limited to no access to block nodes will be able to ingest recent blocks from **limited-history cloud buckets** using the Block Streams format. This serves as a backup alternative during the transitional phase whiles the number of block nodes are increased over time. #### **Why operators should care** This architecture: - Eliminates the cost and maintenance burden of large cloud bucket downloads - Ensures operators keep receiving the full network history - Future-proofs Mirror Node operations for new services such as State Proofs, filtered block queries, and consensus-equivalent state lookup If Mirror Node operators do not upgrade, **data ingestion will fail** once block streams become the canonical network data format. #### **Migration Requirements and Deadlines** Mirror Node operators should begin preparing for the transition from record files to block streams. Operators must deploy a cutover-compatible Mirror Node release ahead of the transition; releases earlier than the minimum supported version will stop ingesting new data once the cutover completes. Failing to validate and upgrade in time will result in: - Loss of network data ingestion - Inability to support future state queries and services - Operational outages for any systems reliant on Mirror Node APIs For the current requirements, including the minimum supported version, timeline, bucket access changes, and validation checks, see the [Mirror Node operator migration guide](https://hedera.com/blog/block-streams-replace-the-record-stream-by-default/) #### **Key Takeaways** - **Block Nodes are now in private preview** across previewnet, testnet, and mainnet, validating HIP-1056 and HIP-1081. - **Community access begins Q1 2026**, enabling early testing and integration. - Block streams will become the canonical network data format once the cutover completes. - Mirror Node operators must deploy a cutover-compatible Mirror Node release ahead of the transition. The current minimum supported version and full requirements are covered in the [Mirror Node operator migration guide](https://hedera.com/blog/block-streams-replace-the-record-stream-by-default/) - Staying current with mirror node versions ensures continued data compatibility and unlocks the benefits of the new block streaming architecture. - Mirror node operators are strongly encouraged to review **HIP-1056 Block Streams** and **HIP-1081 Block Nodes** in preparation for the migration. **Update 01/13/26**: The Mirror Node block stream migration requirements have been finalized. See the [Mirror Node operator migration guide](https://hedera.com/blog/block-streams-replace-the-record-stream-by-default/) #### Reference Links - [HIP 1056: Block Streams](https://hips.hedera.com/hip/hip-1056) - [HIP 1081: Block Node](https://hips.hedera.com/hip/hip-1081) - [HIP 1200: The hinTS threshold signature scheme](https://hips.hedera.com/hip/hip-1200) - [Block Streams & Block Nodes: Advanced Insights & Implementations | HederaCon 2025 | Technical Stage](https://www.youtube.com/watch?v=rrFylGrALd0&list=LL) - [Hiero Block Node Github Repository](https://github.com/hiero-ledger/hiero-block-node) - [Introducing Block Streams: A Unified Data Stream Capturing the Comprehensive History of the Hedera Network](https://hedera.com/blog/introducing-block-streams-a-unified-data-stream-capturing-the-comprehensive-history-of-the-hedera-network) - [5-22-25 Technical Community Call](https://www.youtube.com/watch?v=VZR3KoSsloo&t=3681s) - [9-25-25 Technical Community Call: Blockstreams, Blocknodes & TSS, AI on Hedera, and Hackathons Update](https://www.youtube.com/watch?v=kgg6JKphn9Y) - [10-30-25 Technical Community Call](https://www.youtube.com/live/zaNi0Ff3z-w?si=7gMYkHESQxeyJ-Q0&t=3013) [Back to Blog](/blog) discover See more articles [View All](/blog) September 8, 2026 ### How to unlock the full potential of HCS (and why it is not a database) HCS gives you fair ordering, consensus timestamps, and a tamper-resistant history. Pair it with an index or a database for queries. [Read More](https://hedera.com/blog/how-to-unlock-the-full-potential-of-hcs-and-why-it-is-not-a-database/) September 4, 2026 ### Hedera Council Grows Partner Network with New Strategic and Community Partners WISeKey joins as a Strategic Partner, bringing deep expertise in cybersecurity, digital identity, and IoT, alongside new Community Partner SpaceDev, a Latin American software company expanding Hedera’s reach and adoption [Read More](https://hedera.com/blog/hedera-council-grows-partner-network-with-new-strategic-and-community-partners/) August 31, 2026 ### x402 bounty on Hedera winners announced Meet the five winners of the x402 bounty on Hedera. Each received $1,000 for open source pay-per-request builds running on Hedera testnet. [Read More](https://hedera.com/blog/x402-bounty-on-hedera-winners-announced/) ## Ready to get started? Discover why Hedera is the trusted institutional-grade network powering the new digital economy. [Start Building](/start-building) [Contact](/contact) We use cookies to deliver the best experience on our website and to analyze traffic. By continuing to use this site, you consent to our cookie policy. Review our [Privacy Policy](/privacy) to understand how Hedera collects and uses information. Accept All CookiesAccept Necessary Cookies