Binji explains how Dencun, Pectra and Fusaka will boost L1/L2 scaling

Ethereum scaling is finally easier to talk about if you stop treating every upgrade like it does the same job. It doesn’t. Dencun, Pectra, Fusaka, and Glamsterdam are four different answers to four different bottlenecks. That’s the point Ethereum Foundation developer binji_x was making in a thread that’s useful precisely because it cuts through the usual blob jargon and asks a simpler question — what actually gets faster, and where? (blog.ethereum.org) ### What did Dencun actually change? Dencun, which hit mainnet on March 13, 2024, introduced EIP-4844 — proto-danksharding. The important part is blobs. Before that, rollups mostly posted their data as calldata inside regular Ethereum transactions, which meant they were competing directly with ordinary L1 activity for block space. Blobs created a separate, cheaper data lane for rollups. They are temporary, don’t get executed by the EVM, and were designed specifically to cut L2 posting costs. (blog.ethereum.org) ### Why wasn’t Dencun enough? Because Dencun mostly changed cost, not raw architecture. Rollups got cheaper, which is huge, but every node still had to download every blob. That means the next constraint became bandwidth. You can lower fees with blobs and still hit a ceiling if node requirements rise too fast. Basically, Dencun opened the door to rollup scaling, but it didn’t remove the deeper bottleneck in how the network distributes blob data. (ethereum.org) ### So what was Pectra’s role? Pectra, live since May 7, 2025, was the “more runway” upgrade. It raised blob capacity for rollups — target blobs per block moved from 3 to 6, with a max of 9 under EIP-7691. It also made heavy calldata more expensive under EIP-7623, which nudges rollups away from the old path and into blobs where Ethereum wants scaling to happen. Pectra also bundled in wallet and validator changes, but for scaling the (ethereum.org)ntives. (pectra.org) ### Why does calldata pricing matter? Because if calldata stays too attractive, rollups keep using the expensive shared lane instead of the purpose-built one. Think of it like adding a freight rail line but still underpricing trucks on the highway. Pectra’s calldata repricing was less about making users happy today and more about steering the ecosystem toward the architecture Ethereum can actually scale. That’s why some upgrades feel invisible at first — they’(pectra.org)ust fees. (pectra.org) ### What does Fusaka add on top? Fusaka, scheduled for mainnet on December 3, 2025, is the big blob-throughput unlock because of PeerDAS — Peer Data Availability Sampling. Instead of every node downloading every blob, the protocol moves toward sampling pieces of the data. That cuts the bandwidth burden on individual nodes and lets Ethereum push blob capacity much higher without forcing the network into data-center-only territory. Ethereum.org describes it as r(pectra.org)se in DA capacity for L2s. (blog.ethereum.org) ### Is Fusaka an L2 story or an L1 story? Mostly an L2 scaling story, but with L1 consequences. Cheaper and more abundant blob space means rollups can settle more activity to Ethereum more often. That improves the whole stack’s usable throughput. But it does not mean Ethereum L1 suddenly becomes a high-TPS execution chain in the Solana sense. Fusaka strengthens Ethereum as the settlement and data-availability layer underneath rollups. (blog.ethereum.org) ### Then what is Glamsterdam for? Glamsterdam is where Ethereum turns back toward L1 scaling itself. The upgrade is planned for H1 2026 and focuses on reorganizing processing so the network can prepare for parallel execution, split block-building duties more cleanly, and price storage growth more honestly so future gas-limit increases don’t wreck home-node viability. In plain English — Fusaka helps Ethereum c(blog.ethereum.org)afely and sustainably. (ethereum.org) ### What’s the real takeaway? The clean mental model is this: Dencun created blob space, Pectra expanded it, Fusaka makes it scale properly, and Glamsterdam starts attacking L1 execution limits directly. So when traders or builders ask whether an upgrade is “bullish for scaling,” the better question is where the throughput appears — cheaper L2s, more L2 capacity, or actual L1 performance. On Ethereum now, those are related, but they are not the same thing. (blog.ethereum.org)