What happens when a blockchain decides to scale not by reinventing itself, but by simply dialing up the knobs? On January 7, 2026, Ethereum activated BPO-2—the second Blob Parameters Only fork—quietly completing the Fusaka upgrade's final phase. The result: a 40% capacity expansion that slashed Layer 2 fees by up to 90% overnight. This wasn't a flashy protocol overhaul. It was surgical precision, proving that Ethereum's scalability is now parametric, not procedural.

The BPO-2 Upgrade: Numbers That Matter
BPO-2 raised Ethereum's blob target from 10 to 14 and the maximum blob limit from 15 to 21. Each blob holds 128 kilobytes of data, meaning a single block can now carry approximately 2.6–2.7 megabytes of blob data—up from around 1.9 MB before the fork.
For context, blobs are the data packets that rollups publish to Ethereum. They enable Layer 2 networks like Arbitrum, Base, and Optimism to process transactions off-chain while inheriting Ethereum's security guarantees. When blob space is scarce, rollups compete for capacity, driving up costs. BPO-2 relieved that pressure.
The Timeline: Fusaka's Three-Phase Rollout
The upgrade didn't happen in isolation. It was the final stage of Fusaka's methodical deployment:
- December 3, 2025: Fusaka mainnet activation, introducing PeerDAS (Peer Data Availability Sampling)
- December 9, 2025: BPO-1 increased the blob target to 10 and maximum to 15
- January 7, 2026: BPO-2 pushed the target to 14 and maximum to 21
This staged approach allowed developers to monitor network health between each increment, ensuring that home node operators could handle the increased bandwidth demands.
Why "Target" and "Limit" Are Different
Understanding the distinction between blob target and blob limit is critical for grasping Ethereum's fee mechanics.
The blob limit (21) represents the hard ceiling—the absolute maximum number of blobs that can be included in a single block. The blob target (14) is the equilibrium point that the protocol aims to maintain over time.
When actual blob usage exceeds the target, base fees rise to discourage overconsumption. When usage falls below the target, fees decrease to incentivize more activity. This dynamic adjustment creates a self-regulating market:
- Full blobs: Base fees increase by approximately 8.2%
- No blobs: Base fees decrease by approximately 14.5%
This asymmetry is intentional. It allows fees to drop quickly during low-demand periods while rising more gradually during high demand, preventing price spikes that could destabilize rollup economics.
The Fee Impact: Real Numbers from Real Networks
Layer 2 transaction costs have plunged 40–90% since Fusaka's deployment. The numbers speak for themselves:
| Network | Average Fee Post-BPO-2 | Ethereum Mainnet Comparison |
|---|
| Base | $0.000116 | $0.3139 |
| Arbitrum | ~$0.001 | $0.3139 |
| Optimism | ~$0.001 | $0.3139 |
Median blob fees have dropped to as low as $0.0000000005 per blob—effectively free for practical purposes. For end users, this translates to near-zero costs for swaps, transfers, NFT mints, and gaming transactions.
How Rollups Adapted
Major rollups restructured their operations to maximize blob efficiency:
- Optimism upgraded its batcher to rely primarily on blobs rather than calldata, cutting data availability costs by more than half
- zkSync reworked its proof-submission pipeline to compress state updates into fewer, larger blobs, reducing posting frequency
- Arbitrum prepared for its ArbOS Dia upgrade (Q1 2026), which introduces smoother fees and higher throughput with Fusaka support
Since EIP-4844's introduction, over 950,000 blobs have been posted to Ethereum. Optimistic rollups have seen an 81% reduction in calldata usage, demonstrating that the blob model is working as intended.
The Road to 128 Blobs: What Comes Next
BPO-2 is a waypoint, not a destination. Ethereum's roadmap envisions a future where blocks contain 128 or more blobs per slot—an 8x increase from current levels.
PeerDAS: The Technical Foundation
PeerDAS (EIP-7594) is the networking protocol that makes aggressive blob scaling possible. Instead of requiring every node to download every blob, PeerDAS uses data availability sampling to verify data integrity while downloading only a subset.
Here's how it works:
- Extended blob data is divided into 128 pieces called columns
- Each node participates in at least 8 randomly chosen column subnets
- Receiving 8 of 128 columns (about 12.5% of data) is mathematically sufficient to prove full data availability
- Erasure coding ensures that even if some data is missing, the original can be reconstructed
This approach allows a theoretical 8x scaling of data throughput while keeping node requirements manageable for home operators.
The Blob Scaling Timeline
| Phase | Target Blobs | Max Blobs | Status |
|---|
| Dencun (March 2024) | 3 | 6 | Complete |
| Pectra (May 2025) | 6 | 9 | Complete |
| BPO-1 (December 2025) | 10 | 15 | Complete |
| BPO-2 (January 2026) | 14 | 21 | Complete |
| BPO-3/4 (2026) | TBD | 72+ | Planned |
| Long-term | 128+ | 128+ | Roadmap |
A recent all-core-devs call discussed a "speculative timeline" that could include additional BPO forks every two weeks after late February to achieve a 72-blob target. Whether this aggressive schedule materializes depends on network monitoring data.
Glamsterdam: The Next Major Milestone
Looking beyond BPO forks, the combined Glamsterdam upgrade (Glam for consensus layer, Amsterdam for execution layer) is currently targeted for Q2/Q3 2026. It promises even more dramatic improvements:
- Block Access Lists (BALs): Dynamic gas limits enabling parallel transaction processing
- Enshrined Proposer-Builder Separation (ePBS): On-chain protocol for separating block-building roles, providing more time for block propagation
- Gas limit increase: Potentially up to 200 million, enabling "perfect parallel processing"
Vitalik Buterin has projected that late 2026 will bring "large non-ZK-EVM-dependent gas limit increases due to BALs and ePBS." These changes could push sustainable throughput toward 100,000+ TPS across the Layer 2 ecosystem.
What BPO-2 Reveals About Ethereum's Strategy
The BPO fork model represents a philosophical shift in how Ethereum approaches upgrades. Rather than bundling multiple complex changes into monolithic hard forks, the BPO approach isolates single-variable adjustments that can be deployed quickly and rolled back if problems emerge.
"The BPO2 fork underscores that Ethereum's scalability is now parametric, not procedural," observed one developer. "Blob space remains far from saturation, and the network can expand throughput simply by tuning capacity."
This observation carries significant implications:
- Predictable scaling: Rollups can plan capacity needs knowing that Ethereum will continue expanding blob space
- Reduced risk: Isolated parameter changes minimize the chance of cascading bugs
- Faster iteration: BPO forks can happen in weeks, not months
- Data-driven decisions: Each increment provides real-world data to inform the next
The Economics: Who Benefits?
The beneficiaries of BPO-2 extend beyond end users enjoying cheaper transactions:
Rollup Operators
Lower data posting costs improve unit economics for every rollup. Networks that previously operated at thin margins now have room to invest in user acquisition, developer tooling, and ecosystem growth.
Application Developers
Sub-cent transaction costs unlock use cases that were previously uneconomical: micropayments, high-frequency gaming, social applications with on-chain state, and IoT integrations.
Ethereum Validators
Increased blob throughput means more total fees, even if per-blob fees drop. The network processes more value, maintaining validator incentives while improving user experience.
The Broader Ecosystem
Cheaper Ethereum data availability makes alternative DA layers less compelling for rollups prioritizing security. This reinforces Ethereum's position at the center of the modular blockchain stack.
Challenges and Considerations
BPO-2 isn't without trade-offs:
Node Requirements
While PeerDAS reduces bandwidth requirements through sampling, increased blob counts still demand more from node operators. The staged rollout aims to identify bottlenecks before they become critical, but home operators with limited bandwidth may struggle as blob counts climb toward 72 or 128.
MEV Dynamics
More blobs mean more opportunities for MEV extraction across rollup transactions. The ePBS upgrade in Glamsterdam aims to address this, but the transition period could see increased MEV activity.
Blob Space Volatility
During demand spikes, blob fees can still surge rapidly. The 8.2% increase per full block means sustained high demand creates exponential fee growth. Future BPO forks will need to balance capacity expansion against this volatility.
Conclusion: Scaling by Degrees
BPO-2 demonstrates that meaningful scaling doesn't always require revolutionary breakthroughs. Sometimes, the most effective improvements come from careful calibration of existing systems.
Ethereum's blob capacity has grown from 6 maximum at Dencun to 21 at BPO-2—a 250% increase in under two years. Layer 2 fees have dropped by orders of magnitude. And the roadmap to 128+ blobs suggests this is just the beginning.
For rollups, the message is clear: Ethereum's data availability layer is scaling to meet demand. For users, the result is increasingly invisible: transactions that cost fractions of cents, finalized in seconds, secured by the most battle-tested smart contract platform in existence.
The parametric era of Ethereum scaling has arrived. BPO-2 is proof that sometimes, turning the right knob is all it takes.
Building on Ethereum's expanding blob capacity? BlockEden.xyz provides enterprise-grade RPC services for Ethereum and its Layer 2 ecosystem, including Arbitrum, Optimism, and Base. Explore our API marketplace to connect to the infrastructure powering the next generation of scalable applications.