TL;DR: An experimental high-speed testnet lays the foundation for mainnet. Fibernet ships huge HyperBEAM S3-powered blob capacity, a higher throughput ceiling, deterministic finality, and interoperability with AO.
Load Network is entering its final stage before mainnet.
Over the past year, the network grew to support its core architecture: EVM rails for permanent Arweave storage, temporary object storage via Load S3, and offloaded compute through AO and HyperBEAM. That combination is the foundation of the onchain data center.
But there was still one limitation: the performance ceiling of the underlying consensus. Alphanet was never designed to deliver deterministic finality, and still had room to grow performance to support Arweave’s capacity for storage at any scale.
On the road to mainnet, Fibernet is the next (and final) stop.
In this post, we outline what Fibernet is, why we’re launching it, and how it fits into Load Network’s path to mainnet.
Why Fibernet?
Fibernet is a new testnet built to validate improvements that aren’t possible to test safely on Alphanet. After testing, the network will form the 1:1 basis for Load’s mainnet release. Its focus is on:
- deterministic, sub-second finality,
- higher throughput and data bandwidth,
- EIP-4844 hyper optimizations allowing blob-style handling of large objects,
- tighter integration between EVM, AO compute, and HyperBEAM micro-modularity.
Fibernet is experimental by design. It will change rapidly, fork, and undergo aggressive stress tests. It’s the performance lab for Load - the environment where we push the system to its limits before introducing new capabilities to the stable network.
Alphanet v5 will continue to operate for dApp development, ledger archiving and altDA. Fibernet runs alongside it with a different purpose: to validate whether Load’s architecture scales the way it needs to.
Built on Ultramarine
The core of Fibernet is Ultramarine, Load’s consensus client based on the Malachite BFT engine from Informal Systems (later acquired by Circle, used as Arc L1’s consensus client).
Malachite is a Rust-based deterministic-finality protocol capable of sub-second commit times and high throughput. Ultramarine adapts it to Load’s environment: storage-heavy blocks, blob sidecars, and interactions with the EVM.
Properties like deterministic finality and bandwidth matter far more for data-rich applications than for token transfers. When the objects you settle onchain are large, long-lived, and used downstream in compute pipelines, settlement uncertainty is a real problem. Removing it simplifies developer logic and improves reliability across the entire system.
Blobs + calldata: smart data routing
Fibernet continues Load’s approach to storage: applications decide, per object, what durability and price profile they need.
- Arweave for permanent archival of proofs, blocks, and critical onchain data
- Load S3 for temporary assets, staging, logs, and any data that doesn’t need to live forever – tightly integrated with L1 blobs
- Hybrid storage using xANS-104, allowing applications to move data between temporary and permanent layers programmatically
Blobs in Fibernet get committed to HyperBEAM (Load S3) as ANS-104 DataItems to allow for future routing to Arweave without losing addressability or provenance.
AO / HyperBEAM Integration
Many workloads require computation beyond what the EVM can handle efficiently. Fibernet will test deeper coordination between Load and AO.
On Fibernet, it will be possible to trigger an AO process from the EVM side, and vice versa. Effectively this means that
This makes it possible to compute using the wide range of complex and interesting HyperBEAM devices available for workloads like AI and GPU functions, without forcing those systems entirely offchain.
Who Can Access Fibernet
Access to Fibernet will be gated initially. The first cohort with access will be participants in the Load Fair Launch, i.e., those who delegate stake to help bootstrap the network.
Those who fund the network development should be the first to test it, and any exclusive dApps that deploy there.
Fibernet → Mainnet
Fibernet is not a replacement for Alphanet. Alphanet will run in parallel:
Alphanet will evolve slowly and conservatively since it is already part of the stacks for projects like Metis, Dymension, EigenDA, and Nau Finance. Fibernet will evolve quickly (and probably break often). The lessons from Fibernet will inform the design, performance and security parameters of the Load mainnet.
Evolving to Fibernet
Fibernet is a necessary step for Load Network’s evolution into a high-bandwidth, deterministic-finality data layer. It’s built to test the conditions under which Load can support large datasets, rapid settlement, fast deterministic DeFi and complex compute routing (GPU and other flavors via HyperBEAM devices), all without compromising the simplicity of the EVM.
Fibernet is the stepping stone between the current stable testnet and the future mainnet.
Fair launch participants will be the first to use it.
Stay tuned for more: @useload